Abstract

Three cases are presented of peculiar speech and language abnormalities that were evaluated in the context of personal injury lawsuit or workers compensation claims of brain dysfunction after mild traumatic brain injuries. Neuropsychological measures of effort and motivation showed evidence of suboptimal motivation or outright malingering. The speech and language abnormalities of these cases probably were not consistent with neurogenic features of dysfluent speech including stuttering or aphasia. We propose that severe dysfluency or language abnormalities persisting after a single, uncomplicated, mild traumatic brain injury are unusual and should elicit suspicion of a psychogenic origin.

Possible psychogenic explanations for neuropsychological test abnormalities or symptoms can include malingering and factitious disorders, suboptimal or variable effort, and psychiatric conditions such as depression, anxiety, somatization, or conversion disorder. A variety of methods and measures have been designed to assess the possibility that suboptimal motivation or deliberate production of wrong answers might explain neuropsychological test score abnormalities. These measures include forced choice measures of recognition memory such as the Portland Digit Recognition Test, Test of Memory Malingering, Victoria Symptom Validity Test, and the Word Memory Test (WMT); forced choice measures of visual perception and vocabulary found in the Validity Indicator Profile; and measures of perceptual speed and accuracy including the b Test and Dot Counting. In addition, quantitative indexes of efforts have been applied to neuropsychological measures originally designed to assess cognitive and motor abilities. For example, low scores on Reliable Digit Span, computed from conventional administration of Digit Span, low scores on recognition memory trials of the Rey Auditory Verbal Learning Test (Rey AVLT) or California Verbal Learning Test—Second Edition (CVLT-2), and improbable abnormalities in manual dexterity, strength, and tactile sensation have yielded markers of poor effort (Boone, 2007; Larrabee, 2007, 2012).

There are few guidelines in the literature for distinguishing between psychogenic and neurogenic types of speech and language disorders. Indeed, Seery (2005), a speech and language pathologist, noted that both acquired neurogenic stuttering and acquired psychogenic stuttering had features in common. Both psychogenic- and neurogenic-acquired stuttering disorders had sudden onset and occurred throughout utterances rather than only at the initiation of utterances, as in developmental stuttering. Seery noted that variability of dysfluency was not diagnostic of feigning. However, the lack of improvement in, easier speech conditions, such as speaking in unison, shouting, and speaking while finger tapping, was consistent with malingering. Nonmalingerers were also expected to improve when performing automatic speech tasks such as counting to 10 or reciting the days of the week. Another speech and language pathologist, Duffy (2001), observed that telegraphic and infantile grammatical constructions and physical grimacing and “struggle behavior” was consistent with malingered dysfluent speech.

The neuropsychological literature on the assessment of motivation includes the scant discussion of methods for distinguishing between genuine versus psychogenic or feigned speech and language abnormalities. In contrast, with the extensive neuropsychological literature on psychogenic abnormalities and effort and motivation in other areas of functioning published in the last two decades, we found only two published neuropsychological case studies of psychogenic speech and language abnormalities. Axelrod (2009) reported two cases of minor head injury seen for litigation purposes that likely had psychogenic causation of speech and language abnormalities. The first case was a woman with many nonorganic features that began many months after a minor head injury. In contrast to fluent speech in a prior neuropsychological evaluation, Axelrod observed incorrect combinations of present and past tense in the same sentences. Her speech was intermittently telegraphic and consistently slow and monotonic, and her language sometimes did not convey coherent information. On a forced-choice measure of motivation to remember, she performed significantly worse than chance, and on the WAIS-R her prior post-injury Verbal IQ of 85 fell to a Verbal IQ of 52. The second case involved serious eye injury but no serious brain injury. This woman spoke haltingly during the evaluation but fluently immediately afterwards. Speech comprehension was also much improved when she was observed later. Testing of motivation to remember was consistent with deliberate production of incorrect answers. Axelrod concluded that the presentations of both cases were implausible.

In another case that occurred after a mild head injury in the context of litigation for personal injuries (Cottingham & Boone, 2010), the examinee initially had abnormalities in articulation, expression, and comprehension of oral language that later evolved into a foreign accent syndrome. Her history of longstanding, unexplained medical problems led to diagnoses of somatization and conversion disorders. Failure on some measures of efforts left the authors unable to exclude the possibility of intentional feigning of deficits or malingering.

With so little available neuropsychological literature describing speech and language abnormalities of psychogenic origin, we felt that analysis of case material would prove informative. The cases presented here were adults in litigation seeking monetary damages in personal injury lawsuits or workers compensation claims referred for independent forensic neuropsychological evaluations to the private practices of the authors. In all cases, brain injuries were alleged to have resulted from relatively minor head injuries, and the examinees presented with speech or language abnormalities that were atypical of neurogenic disorders. All cases demonstrated evidence of poor effort on neuropsychological testing, and some had nonorganic neurological abnormalities. Although prior examiners, especially in one case, had expressed skepticism about the etiology of the speech and language abnormalities, the independent neuropsychological evaluations served to document the psychogenic or malingered origin of the presentations of these examinees.

Case 1

Case 1, a right-handed female investment advisor in her mid-40s, allegedly was injured when her vehicle was struck from the rear in a motor vehicle accident (MVA). She first sought medical care 5 days after the MVA when she complained of neck and back pain. Onset of stuttering was 11 days after the accident. A month after the MVA, a neurologist described stuttering and speech blocking with intact language, breakaway weakness in all four extremities, and incoordination of her left upper extremity. A brain MRI was normal.

The number and severity of the abnormalities continued to grow. A neurologist observed astasia-abasia, a term typically reserved for a nonorganic abnormality of gait (Albers & Schiffer, 2007). Her facial sensation abnormality split the midline, another nonorganic neurological feature. On day 105, she saw a rehabilitation medicine physician who noted language problems including omitting articles and the endings of verbs and clear neurological inconsistencies including failure to dorsiflex the foot during the examination but not when she walked.

After seeing the rehabilitation physician, she wrote a perfectly grammatical letter in which she claimed that she had difficulty with the clock drawing test during the recent examination, disputing the examiner's opinion that the drawing was normal.

By that time, her neurologist had characterized her speech as baby talk that was markedly different than her initial presentation. He noted other inconsistencies that he felt were nonorganic, and he diagnosed a conversion disorder. She traveled 1,450 kilometers to see another neurologist who also diagnosed a psychogenic speech disorder and noted that she angrily left his office before he finished providing feedback to her.

Only brief summaries of her initial neuropsychological evaluations by other examiners are available. Five months after her injury, she reportedly failed measures of effort including the Rey Fifteen Items Test although her precise score was not reported. Her grip strength was severely abnormal with scores of 1.5 kg on the right and 3.0 kg on the left. Her scores on Finger Tapping of 8 on each hand were far below the cutoff for psychogenic problems (Greiffenstein, 2007; Greiffenstein, Baker, & Gola, 1996) or malingering (Larrabee, 2003). Her times on Trail Making were implausibly poor, compared with persons with mild traumatic brain injury (Backhaus, Fichtenberg, & Hanks, 2004) with times of 144 s on Part A and 244 s on Part B, and on the vigilance task of the Gordon Diagnostic System, an extremely easy task where the mean for normal adults is nearly perfect (M. Gordon, personal communication, December 30, 2009), she made omission errors on all 30 items. The first neuropsychologist concluded that she was disabled on a psychological basis.

After 12 months, she received an electronystagmogram (ENG) that was abnormal, but the audiologist stated that Case 1 admitted that she had not been cooperative, and the neurologist noted that the ENG contained excessive muscle artifact. An EEG was normal. At month 13, another SLP observed inconsistent speech. She was able to voice “T” and “D” sounds in the beginning of words but not at the end, and pronunciation of these sounds in the middle of words was inconsistent.

Sixteen months after her accident, in an examination requested in connection with her application for Social Security benefits, WAIS-III Verbal IQ was 55, Performance IQ was 50, and Full Scale IQ was 48. Digit span was two forwards and zero backwards. Although her Reliable Digit Span was not reported, it could not have been greater than two, a performance consistent with psychogenic or feigned impairment (Jasiski,, Berry, Shandera, & Clark, 2011), especially in the context of a minor initial injury. On the WMS-III, she received these index scores: Auditory Immediate 56, Visual Immediate 53, Immediate 45, Auditory Delay 61, Visual Delay 53, Auditory Recognition Delayed 55, General Memory 47, Working Memory 49. On recognition memory testing on the WMS-III, she denied prior exposure to virtually all target and distractor items. She did not complete Part A or Part B of Trail Making.

After 17 months, a neuro-otologist performed another ENG with normal results. In another test, the neuro-otologist noted voluntary interruption of eye movements. On the posturography test, excessive voluntary movement reportedly made it difficult to interpret the data. She claimed bowel and bladder incontinence for the first time.

A fourth neurologist examined her 17 months after the injury. A letter to him contained crude handwriting, grammatical errors, and the phrase “low the mawn” instead of the intended phrase of “mow the lawn.” Although someone with aphasia or other speech or language disturbance conceivably might say “low the mawn,” it seems unlikely to us that someone would make a genuine error of writing this phrase. Among the examples of poor grammar in this letter to the neurologist was the phrase “[someone] want me tell you” with the first person form of “want” used instead of the correct third person form. This same letter contained intact spelling. The deterioration in her written language skill after 17 months cannot be explained neurologically.

During her videotaped deposition 30 months after the MVA, she made inconsistent errors of speech and language. Pronunciation of individual sounds and syllables often was labored. Her utterances included the following language errors and inconsistencies: “I not know how old I be …. Can you do for me? … I have two stepdaughter.” The preceding failure to use the plural noun was inconsistent with at least one correct usage of a plural noun. Other utterances included, “Lots of good friends. One live in Northern California …. Two-six …. [when expressing 26, but she correctly uttered ‘12’]. I no think … .” Her speech errors included omitting middle consonants, that is, the name “Kevin” pronounced as “Ke-an” and the phrase “after the accident” pronounced as “af-er accent.” Later, she pronounced “accident” as “asident.” In contrast, she correctly pronounced this linguistically incorrect sentence: “I can no separate from you words” and she correctly pronounced, “temporarily.”

Articulatory and language inconsistencies also included sometimes mispronouncing the “th” sound as “f” in the middle of words such as “Mefodis” rather than “Methodist” and yet correctly pronouncing the “th” sound in “think,” “with,” and “the.” She sometimes used “no” instead of “am not,” for example, “I no working.” She usually used the present tense when referring to the past, even in the same sentence that included the use of the past tense such as “I just got done tell you,” sometimes deleting articles, sometimes omitting “was,” but sometimes including it correctly, as in “how I was feeling.” At times she correctly pronounced “Massachusetts,” and sometimes she said “Massatusett.” She used the phrase “I not,” but at other times she correctly said “I am not.” She pronounced “okay” correctly when reading aloud, but she spontaneously said “ohay,” omitting the consonant.

At times during her deposition, she responded concretely. When asked “How do you support yourself”?, she acted as though she interpreted the question to be about her ability to stand. When asked if a seatbelt had been “engaged” by the impact of the collision, she responded as though the question was about a marriage engagement married.

In the examination by the first author 31 months after the MVA, she was observed to speak normally on the telephone, but generally she spoke with the same errors in speech and language as in her deposition. She was carefully made up, coiffed, and groomed (Table 1).

Table 1.

Case 1: Author's Neuropsychological Evaluation

Symptom Validity Tests   
 Rey 15 Item Recall 2 (fail)  
 Rey 15 Item Recognition 2 (fail)  
 TOMM Trial 1 24 (fail)  
 TOMM Trial 2 33 (fail)  
 TOMM Trial 3 35 (fail)  
 Reliable Digit Span 3 (fail)  
 PDRT Easy 27/36 (pass)  
 PDRT Hard 13/18 (pass, test discontinued because of good performance)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Grip Strength right 1 kg <1 
 Grip Strength left 0 kg <1 
 Finger Tapping right <1 
 Finger Tapping left <1 
 Finger Localization right 10 errors <1 
 Finger Localization left 8 errors <1 
 Finger Graphesthesia right 13 errors <1 
 Finger Graphesthesia left 13 errors <1 
 WAIS-III Verbal IQ 87  
 Performance IQ 70  
 Full-scale IQ 77  
 Verbal Comprehension 101  
 Perceptual Organization 78  
 Working Memory 61  
 Processing Speed 50  
 Vocabulary 11  
 Similarities  
 Arithmetic  
 Digit Span  
 Information 13  
 Comprehension  
 Letter Number Sequencing  
 Picture Completion  
 Digit Symbol Coding  
 Block Design  
 Matrix Reasoning  
 Symbol Search  
 Boston Naming 57/60 Average 
 WMS-III Logical Memory I 
 Scaled Score 
 WMS-III Logical Memory II Scaled Score 
 Rey AVLT Learning Trials 1–5 2,4,5,5,5 (Total 21) Total <1 
 Rey AVLT Short Delay 
 Rey AVLT Long Delay 
 Rey AVLT Recognition 6 correct, 1 intrusion 
 Wisconsin Card Sorting-64 One concept 6–10 
54 perseverative responses <1 
 Token Test Part V 21/42 correct <1 
Symptom Validity Tests   
 Rey 15 Item Recall 2 (fail)  
 Rey 15 Item Recognition 2 (fail)  
 TOMM Trial 1 24 (fail)  
 TOMM Trial 2 33 (fail)  
 TOMM Trial 3 35 (fail)  
 Reliable Digit Span 3 (fail)  
 PDRT Easy 27/36 (pass)  
 PDRT Hard 13/18 (pass, test discontinued because of good performance)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Grip Strength right 1 kg <1 
 Grip Strength left 0 kg <1 
 Finger Tapping right <1 
 Finger Tapping left <1 
 Finger Localization right 10 errors <1 
 Finger Localization left 8 errors <1 
 Finger Graphesthesia right 13 errors <1 
 Finger Graphesthesia left 13 errors <1 
 WAIS-III Verbal IQ 87  
 Performance IQ 70  
 Full-scale IQ 77  
 Verbal Comprehension 101  
 Perceptual Organization 78  
 Working Memory 61  
 Processing Speed 50  
 Vocabulary 11  
 Similarities  
 Arithmetic  
 Digit Span  
 Information 13  
 Comprehension  
 Letter Number Sequencing  
 Picture Completion  
 Digit Symbol Coding  
 Block Design  
 Matrix Reasoning  
 Symbol Search  
 Boston Naming 57/60 Average 
 WMS-III Logical Memory I 
 Scaled Score 
 WMS-III Logical Memory II Scaled Score 
 Rey AVLT Learning Trials 1–5 2,4,5,5,5 (Total 21) Total <1 
 Rey AVLT Short Delay 
 Rey AVLT Long Delay 
 Rey AVLT Recognition 6 correct, 1 intrusion 
 Wisconsin Card Sorting-64 One concept 6–10 
54 perseverative responses <1 
 Token Test Part V 21/42 correct <1 

Considering the totality of the history, including prior neurocognitive and neurological examinations, the progressive nature of her symptoms after a minor injury, her neuropsychological presentation was consistent with blatant malingering. She failed two of the three measures of motivation to remember including the Test of Memory Malingering and the Rey 15 Item Test with a recognition memory extension (Boone, Salazar, Lu et al., 2002), although she performed adequately on the Portland Digit Recognition Test. Her performance on embedded measures of effort including Reliable Digit Span score of 3 (Jansinski et al., 2011), recognition score on the Rey AVLT (Lu, Rogers, & Boone, 2007), Finger Tapping, Grip Strength, and tactile sensory scores (Arnold & Boone, 2007; Greiffenstein, 2007) also were diagnostic of malingering. For example, the grip strength cutoff for probable malingering in a known group study with a large sample was 16 kg, for the sum of both hands (Greiffenstein & Baker, 2006) compared with her sum of 1 kg. Her finger tapping scores were similarly implausible, considering the lack of any genuine neurologic deficit and her normal ability to perform tasks requiring some strength and dexterity such as opening doors and completing the MMPI-2 at a computer keyboard. Her Reliable Digit Span score was well below the cutoff. Her WAIS-III scores, although abnormal in comparison with her estimated pre-MVA baseline, were much improved compared with the scores reported above that were obtained in a previous evaluation in connection with her SSDI application. The WAIS-III and PDRT results indicated some attempt to avoid the detection of malingering by providing some correct responses.

The attorney who filed a personal injury lawsuit on her behalf ceased representing her. Attorney–client privilege made it impossible to learn the reason for the termination of their legal relationship. The attorney for the defendant confronted her before trial with the evidence of malingering, and she agreed to abandon her lawsuit.

Case 2

This right-handed 41-year-old male truck driver with 11 years of education was referred to the second author for neuropsychological evaluation approximately 3 months after he was struck on the head by an industrial roll of paper that had slipped from an overhead stack. He reported that he was briefly knocked unconsciousness and reported little additional span of post-concussive amnesia.

He was taken to a local university-affiliated medical center, where he was examined, observed overnight for his complaints of headaches, right shoulder pain, and tinnitus, and released to his home. Neurologic examination and neurodiagnostic studies were interpreted as normal with no evidence of skull fracture, subdural or epidural hematoma, cortical contusion, and intraparenchymal hemorrhage or CSF leak. He sustained no worse than a mild head injury, in all likelihood a Grade III concussion.

Case 2 subsequently complained of a wide range of allegedly disabling physical, cognitive, speech-language, and emotional difficulties. In addition to neck pain, shoulder pain, and headaches, he complained of dizziness, vertigo, blurred vision, tinnitus, sleep disturbance, and daytime fatigue. Cognitive complaints included memory deficits, attention problems, organizational difficulties, word-finding and name-finding problems, accompanied by a waxing and waning stammer. Emotional complaints included depression, anxiety, and persistent worrying. He had not returned to work because of his injury.

During clinical interview and standardized testing, his speech was at times pressured and at other times sluggish and meandering. He repeated the first sound in a given word, typically the first word in a sentence or phrase, but sometimes every word in a short sentence, no more or less than three times, for example, “He-he-he shou-shou-shou-ted the-the-the war-war-war-ning” or “No-no-no ifs ands or buts.” This stammer disappeared completely as the examiner forced or altered the pace of the interview, or when Case 2 became irritated or angry (Table 2).

Table 2.

Case 2: Author's Neuropsychological Evaluation

Symptom Validity Tests 
 VSVT Easy 22/24  
 VSVT Hard 13/24 (fail)  
 WMT Immed Recog 67.5% (fail)  
 WMT Delayed Recog 62.5% (fail)  
 WMT Consistency 67.5% (fail)  
 WMT Multiple Choice 40%  
 Reliable Digit Span 6 (fail)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Finger Tapping right (dom) 17 <1 
 Finger Tapping left 17 <1 
 Grooved Pegboard right (dom) 184 s <1 
 Grooved Pegboard left 158 s <1 
 WASI Verbal IQ 89  
 WASI Performance IQ 79  
 WASI Full-scale IQ 83  
 WASI Vocabulary  
 WASI Similarities  
 WAIS III Digit Span  
 WASI Block Design  
 WASI Matrix Reasoning  
 WAIS III Coding  
 Boston Naming 54/60 30 
 Thurstone Fluency 20 (16/4) 
 Controlled Oral Word Association 35 34 
 Rey Figure Copy 26/36 raw  
 Rey Figure 3 min Recall 37 T 
Rey Figure 30 min Recall 49 T 47 
 Rey Figure Delayed Recognition 39 T 14 
 CVLT-II 1–5 Total 31 T 
 CVLT II Trial I (raw)  
 CVLT –II Trial 5 (raw)  
 CVLT-II Trial B (raw)  
 CVLT-II SDFR (raw)  
 CVLT-II LDFR (raw) 10  
 CVLT-II LD Recognition (raw) 14/16 (8 FP)  
 CVLT-II Forced Choice (raw) 13/16 correct  
 Trail Making Test Part A 85 s (0 errors) <1 
 Trail Making Test Part B 135 s (0 errors) 
 WCST—Errors 91 <1 
 WCST—Categories 1 or below 
MMPI-2 
 L 65  
 F 79  
 K 45  
 FBS-Raw 30  
 Hs 92  
 D 91  
 Hy 84  
 Pd 72  
 Mf 60  
 Pa 75  
 Pt 83  
 Sc 94  
 Ma 56  
 Si 55  
Symptom Validity Tests 
 VSVT Easy 22/24  
 VSVT Hard 13/24 (fail)  
 WMT Immed Recog 67.5% (fail)  
 WMT Delayed Recog 62.5% (fail)  
 WMT Consistency 67.5% (fail)  
 WMT Multiple Choice 40%  
 Reliable Digit Span 6 (fail)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Finger Tapping right (dom) 17 <1 
 Finger Tapping left 17 <1 
 Grooved Pegboard right (dom) 184 s <1 
 Grooved Pegboard left 158 s <1 
 WASI Verbal IQ 89  
 WASI Performance IQ 79  
 WASI Full-scale IQ 83  
 WASI Vocabulary  
 WASI Similarities  
 WAIS III Digit Span  
 WASI Block Design  
 WASI Matrix Reasoning  
 WAIS III Coding  
 Boston Naming 54/60 30 
 Thurstone Fluency 20 (16/4) 
 Controlled Oral Word Association 35 34 
 Rey Figure Copy 26/36 raw  
 Rey Figure 3 min Recall 37 T 
Rey Figure 30 min Recall 49 T 47 
 Rey Figure Delayed Recognition 39 T 14 
 CVLT-II 1–5 Total 31 T 
 CVLT II Trial I (raw)  
 CVLT –II Trial 5 (raw)  
 CVLT-II Trial B (raw)  
 CVLT-II SDFR (raw)  
 CVLT-II LDFR (raw) 10  
 CVLT-II LD Recognition (raw) 14/16 (8 FP)  
 CVLT-II Forced Choice (raw) 13/16 correct  
 Trail Making Test Part A 85 s (0 errors) <1 
 Trail Making Test Part B 135 s (0 errors) 
 WCST—Errors 91 <1 
 WCST—Categories 1 or below 
MMPI-2 
 L 65  
 F 79  
 K 45  
 FBS-Raw 30  
 Hs 92  
 D 91  
 Hy 84  
 Pd 72  
 Mf 60  
 Pa 75  
 Pt 83  
 Sc 94  
 Ma 56  
 Si 55  

Neuropsychological evaluation found Case 2 to be performing in low average range of intellectual functioning. He performed unusually poorly on subtests known to be relatively impervious to the effects of brain injuries. His performance across testing most closely resembled that of subjects meeting empirical criteria for malingering (Boone, 2007; Larrabee, 2007, 2012). Case 2 performed below critical levels on two symptom validity procedures demonstrated to be sensitive to the effects of embellished or feigned deficit, the Victoria Symptom Validity Test and the WMT. In addition, his scores on embedded measures of effort including Finger Tapping, Reliable Digit Span, and CVLT-II Forced Choice fell below the published cutoffs for poor effort. In combination, the total of five failed symptom validity tests and embedded measures provided overwhelming statistical evidence that Case 2 was intentionally spoiling his test performance (Larrabee, 2012). His MMPI-2 FBS score was consistent with exaggeration of symptoms.

The performance on the remainder of the evaluation revealed widespread and sometimes implausibly severe abnormalities in higher cognitive functioning. In general, pattern, extent, and progress of deficits were inconsistent with that seen after much more severe and objectively demonstrable traumatic brain injuries. The MMPI-2 revealed compelling evidence of emotional distress, marked by affective symptoms, somatization, and physical symptom exaggeration. The overall results provided compelling evidence of exaggerated or feigned disability behaviors.

Case 3

Case 3, a 37-year-old right-handed woman, was referred to the third author for an independent evaluation in connection with a personal injury lawsuit. A primary care physician's note indicated that she was injured in a horse jumping accident. After 30 min, she felt dazed, dizzy, and disoriented, but she did not seek treatment that day. The next day, she also developed pain in her neck, difficulty remembering things, and trouble with her speech. Her physician obtained a normal head CT scan and a normal cervical X-ray and diagnosed a concussion.

A neurologic evaluation 2 weeks later reported more detailed history. She did not lose consciousness in the fall. The absence of posttraumatic amnesia was suggested by her report that immediately after she fell off the horse, she quickly stood up so that the horse would not stomp her. The neurologic examination was normal, with the exception of word-finding difficulty. The neurologist's impressions were of concussion and post-concussion syndrome. When she returned to see the neurologist after a vacation abroad, she reported intermittent stuttering. She gave the neurologist a 21-point list of her different symptoms and complaints, having largely to do with trouble focusing, concentrating, and remembering since returning from Europe.

She subsequently developed progressively slurred speech, which had become severe, with persistent stuttering. A second CT scan of her head was normal. Her neurologist stated that her stuttering was not the result of an axonal injury from the horse riding accident.

She consulted a second neurologist who reported problems with stuttering and poor attention span. EEG, carotid ultrasounds, and an MRI of the brain were normal. This neurologist diagnosed probable post-traumatic stress syndrome.

Speech therapy then focused on problems with stuttering, executive function, and other cognitive skills. During several months of treatment, the speech therapist noted a significant progress.

She was referred for neuropsychological evaluation to a clinician who did not administer any formal effort tests. However, the test results were internally inconsistent, particularly within the domain of verbal memory, with impaired performances on Wechsler Memory Scale-III (WMS-III) with Logical Memory I scaled score of 3 and Logical Memory II scaled score of 6 contrasted with excellent performances on the Rey AVLT (Total Learning 80th percentile, Post Interference recall 88th percentile, Delayed recall 84th percentile). Personality testing with the MMPI-2 revealed significant elevations on Hy (T= 73) and Pa (T= 67). The neuropsychologist diagnosed post-concussion syndrome.

Her attorney referred her to a second neuropsychologist; raw data from this examination were unavailable. On the Portland Digit Recognition Test (PDRT), she reportedly “performed abysmally” on the easiest items. She complained that she simply could no longer remember numbers after her fall, and he stopped administration of the PDRT. On the WMT, the report stated that she also performed poorly, missing easy word associations. This neuropsychologist then administered the PDRT again, after informing her that it was a test of malingering that she must pass. Nonetheless, she reportedly failed again (see Youngjohn, Lees-Haley, & Binder, 1999 for a discussion of the issues involved in warning examinees who demonstrate poor effort). Despite the multiple failed effort tests, the second neuropsychologist opined that she was brain damaged and that her marital separation was due to a profound loss of cognitive function from the brain injury.

Medical records dated before the horse riding accident revealed a probable pre-existing somatoform disorder. During the years preceding the horse riding accident, she had complaints of and/or was worked up for fatigue, goiter, toothache, headaches, neuropathic pain, migraine, nausea, epigastric pain, and esophageal carcinoma, and she was evaluated by a cardiologist for cardiovascular disease. Each of the specialists indicated that she had none of these conditions, and one consultant stated that she had “a great deal of anxiety and a need for reassurance.” Included in the pre-injury medical records was a 5-page letter to one of these doctors, in which she described a number of similar symptoms to those she reported following her horse riding accident, including chronic pain, nausea, dizziness, diaphoresis, cognitive difficulties, memory problems, headache, anxiety, and losing her temper easily. Her letter described “starting my journey, visiting one doctor after another to try and figure out what was truly wrong.” She also reported feeling resentment towards her doctors. Her letter stated that she knew that one of her doctors “thinks that I am crazy and that I am being high maintenance.”

During the examination by the third author 40 months after the injury, she had peculiar speech, with poor fluency, long pauses between initiation of individual words, very distinct pronunciation of individual words, and generally labored speech production. She over-stressed and exaggerated ending consonants of many words, particularly the letter T. Other times, she extended pronunciation of single syllables, for example, “I think itt waaass … .”

She displayed inconsistent stuttering that waxed and waned during the interview, was less pronounced during test administration, and seemed to worsen when her attention was drawn to it. Her stuttering was most often comprised of repetition of single syllable words. For example, when asked a question, she responded, “You need to be- be- be- be specific.” When describing her injury, she said, “We-we- we were trying to gettt the horse out of the stall,” and “I did did not, I did didn't own a horse,” Sometimes the repeated syllables were inserted and bore no relationship to her utterance, for example, “So I ma ma cannot talk with that type of speech.”

Less frequently, she stuttered on beginning consonants of multiple syllable words. For example, “My bu-bu-brother has Down's Syndrome. There was a lot of pressure on our family not to have conflict.” Another instance of this occurred as she described her “di-di-divorce,” after the horse riding accident. This clearly abnormal speech was interspersed with speech that had normal pace, fluency, and prosody.

She had detailed memories of the injury, demonstrating the absence of post-traumatic amnesia. Since the accident, in addition to stuttering, she reported memory problems, difficulty concentrating, and “an executive function disorder.” She claimed that she could not dress herself. By way of example, she said that she would wear “disco shoes in the daytime. I really struggled caring for myself. My friends would ask, ‘What are you wearing?!”

Her voice quavered when describing her “triumph to master” completion of everyday tasks. She displayed strong suggestibility and marked over-reliance on repression and denial as psychological defenses (Table 3).

Table 3.

Case 3: Author's Neuropsychological Evaluation

Symptom Validity Tests 
 Dot Counting Test E-Score: 17  
 WMT Immediate Recognition 77.5% (fail)  
 WMT Delayed Recognition 90%  
 WMT Consistency 87.5%  
 PDRT Easy 27/36  
 PDRT Hard 19/36 (fail)  
 Reliable Digit Span 6 (fail)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Grip strength right 26 kg 24 
 Grip Strength left 23.5 kg 24 
 Finger Tapping right 52 79 
 Finger Tapping left 46.2 69 
 Grooved Pegboard right 61 s 54 
 Grooved Pegboard left 59 s 82 
 WAIS-IV full-scale IQ 82  
 Verbal Comprehension 96  
 Perceptual Reasoning 84  
 Working Memory 74  
 Processing Speed 81  
 Vocabulary (scaled scores)  
 Similarities  
 Arithmetic  
 Digit Span  
 Information 10  
 Block Design  
 Matrix Reasoning  
 Symbol Search  
 Visual Puzzles  
 Coding  
 WMS-III Immediate Memory 73  
 General (Delayed) Memory 72  
 Auditory Immediate Memory 77  
 Auditory Delayed Memory 74  
 Auditory Delayed Recognition 80  
 Visual Immediate Memory 78  
 Visual Delayed Memory 75  
 Working Memory 91  
 Logical Memory I (scaled scores)  
 Logical Memory II  
 Faces I  
 Faces II  
 Verbal Paired Associates I  
 Verbal Paired Associates II  
 Family Pictures I  
 Family Pictures II  
 Letter-Number Sequencing  
 Spatial Span 10  
 BVRT Correct (raw scores) 45 
 BVRT Errors 61 
 Trail Making A 19 s 74 
 Trail Making B 67 s 88 
 WCST Categories >16 
 WCST Errors 15 61 
 WCST Perseverations 63 
MMPI-2-RF   
 VRIN-r 34  
 TRIN-r 57F  
 F-r 51  
 Fp-r 42  
 Fs 58  
 FBS-r 70  
 L-r 71  
 K-r 66  
 RCd 46  
 RC1 63  
 RC2 46  
 RC3 34  
 RC4 39  
 RC6 43  
 RC7 38  
 RC8 39  
 RC9 36  
 MLS 69  
 GIC 64  
 HPC 65  
 NUC 53  
 COG 75  
Symptom Validity Tests 
 Dot Counting Test E-Score: 17  
 WMT Immediate Recognition 77.5% (fail)  
 WMT Delayed Recognition 90%  
 WMT Consistency 87.5%  
 PDRT Easy 27/36  
 PDRT Hard 19/36 (fail)  
 Reliable Digit Span 6 (fail)  
Neuropsychological Test Raw or scaled score Percentile or level 
 Grip strength right 26 kg 24 
 Grip Strength left 23.5 kg 24 
 Finger Tapping right 52 79 
 Finger Tapping left 46.2 69 
 Grooved Pegboard right 61 s 54 
 Grooved Pegboard left 59 s 82 
 WAIS-IV full-scale IQ 82  
 Verbal Comprehension 96  
 Perceptual Reasoning 84  
 Working Memory 74  
 Processing Speed 81  
 Vocabulary (scaled scores)  
 Similarities  
 Arithmetic  
 Digit Span  
 Information 10  
 Block Design  
 Matrix Reasoning  
 Symbol Search  
 Visual Puzzles  
 Coding  
 WMS-III Immediate Memory 73  
 General (Delayed) Memory 72  
 Auditory Immediate Memory 77  
 Auditory Delayed Memory 74  
 Auditory Delayed Recognition 80  
 Visual Immediate Memory 78  
 Visual Delayed Memory 75  
 Working Memory 91  
 Logical Memory I (scaled scores)  
 Logical Memory II  
 Faces I  
 Faces II  
 Verbal Paired Associates I  
 Verbal Paired Associates II  
 Family Pictures I  
 Family Pictures II  
 Letter-Number Sequencing  
 Spatial Span 10  
 BVRT Correct (raw scores) 45 
 BVRT Errors 61 
 Trail Making A 19 s 74 
 Trail Making B 67 s 88 
 WCST Categories >16 
 WCST Errors 15 61 
 WCST Perseverations 63 
MMPI-2-RF   
 VRIN-r 34  
 TRIN-r 57F  
 F-r 51  
 Fp-r 42  
 Fs 58  
 FBS-r 70  
 L-r 71  
 K-r 66  
 RCd 46  
 RC1 63  
 RC2 46  
 RC3 34  
 RC4 39  
 RC6 43  
 RC7 38  
 RC8 39  
 RC9 36  
 MLS 69  
 GIC 64  
 HPC 65  
 NUC 53  
 COG 75  

Notes: BVRT = Benton Visual Retention Test; CVLT-II = California Verbal Learning Test—second edition; FBS = MMPI-2 Symptom Validity Scale; PDRT = Portland Digit Recognition Test; Rey AVLT = Rey Auditory Verbal Learning Test; TOMM = Test of Memory Malingering; VSVT = Victoria Symptom Validity Test; WASI = Wechsler Abbreviated Scale of Intelligence; WCST = Wisconsin Card Sorting Test; WMS-III = Wechsler Memory Scale—third edition; WMT = Word Memory Test.

Her neuropsychological test results were compromised by poor effort. Reliable Digit Span score of 6 fell below the suggested cutoff (Jasiski et al., 2011). The WMT performance was above the cutoff with 90% specificity recommended by Greve, Ord, Curtis, Bianchini, & Brennan (2008), but she failed on Immediate Recognition according to the test author's cutoff score. Her Dot Counting E-score, although better than the recommended cutoff, was consistent with poor effort; assuming a base rate of poor effort of 40% (Larrabee, 2012), the positive predictive value of her score was over 63% (Boone, Lu, & Herzberg, 2003). She failed the PDRT hard items at 98% specificity for an inadequate effort and 98% positive predictive value (Binder & Kelly, 1996; Greve & Bianchini, 2006). The odds of malingering were calculated using the prevalence of poor effort in the medicolegal population of the third author of approximately 40% (Thomas & Youngjohn, 2009; Youngjohn, Burrows, & Erdal, 1995; Youngjohn, Wershba, Stevenson, Sturgeon, & Thomas, 2011). Chaining of likelihood ratios (Larrabee, 2012) was based on classification statistics for Dot Counting, PDRT, and WMT (Boone et al., 2003; Greve & Bianchini, 2006; Greve et al., 2008), yielding a probability <.99 of poor effort.

MMPI-2-RF validity scale profile revealed modest elevations on L-r (71), FBS-r (70), and K-r (66). The RC scale profile yielded a subclinical elevation on RC1 (63). There were multiple elevations on the somatic/cognitive scales, including COG (75), MLS (69), and HPC (65). This somatic/cognitive scale configuration has been associated in the literature with exaggeration of cognitive and physical complaints and disability in head-injured litigants (Gervais, Ben-Porath, & Wygant, 2009; Youngjohn et al., 2011).

In light of the current and previous failures on effort testing, the current and previous personality test results suggesting somatic symptom magnification, and the absence of objective indications of brain injury, it was concluded that the recent onset of stuttering could not be attributed to traumatic brain injury. Rather, it was felt to have arisen from a pre-existing somatoform disorder, with financial incentives to maintain a disabled status possibly playing a role.

Discussion

Cases that present with severe dysfluency or language abnormalities persisting after a single, uncomplicated mTBI are unusual and should elicit suspicion of a non-neurogenic origin. We propose that there is no reasonable neurological mechanism of mTBI that would cause persistent language or fluency disorders of the magnitude reported in the present paper. Severe persisting speech and language abnormalities after mTBI are not commonly reported by people with symptoms attributed to the effects of prior concussions (Binder, 1997; National Center for Injury Prevention and Control, 2003). Communication impairment after mTBI is not detected by traditional measures used to assess aphasia because deficits are found only in higher order linguistic skills (Duff, Proctor, & Haley, 2002). Although some mTBI patients complain of word retrieval symptoms, language measures from the WAIS-R and the Woodcock-Johnson-III showed no abnormalities beyond the sub-acute stage (Dikmen, Machamer, Winn, & Temkin, 1995; Parrish, Roth, Roberts, & Davie, 2009). Additional evidence that such severe, persisting speech and language problems are inconsistent with mTBI are a series of meta-analytic reviews that showed little or no evidence of incomplete neuropsychological recovery within about 3 months of the injury (reviewed in McCrea, 2008). Furthermore, there is no meta-analytic support for the view that a subgroup of mTBI patients experience persistent neuropsychological abnormalities (Rohling, Larrabee, & Millis, 2012). Persisting cognitive symptoms after single, uncomplicated mTBIs are typically caused by factors other than permanent brain injury (McCrea, 2008). The unusual nature of the severe speech and language abnormalities in the cases presented here with history of normal brain imaging and, at worst, uncomplicated mTBI suggested poor effort or malingering that was confirmed in all cases by neuropsychological testing.

Case 1 had unusual language and articulation abnormalities. Unlike Cases 2 and 3, stuttering was not a primary feature of her presentation. Case 1 had many historical features and objective findings that suggested a psychogenic etiology to her complaints. The severity of the neuropsychological abnormalities, such as WAIS-III Full Scale IQ score of 48 when seen for an earlier evaluation, dictates that she should have had unequivocal initial signs of a traumatic brain injury. Instead, she did not seek medical attention until 5 days elapsed after her MVA when there was no concern about a brain injury. Her course then deteriorated. The delayed onset of the language abnormalities was not consistent with a neurogenic cause given the normal neuroimaging that failed to show evidence of a structural lesion such as a subdural hematoma that might have slowly evolved after a brain injury. In the initial neuropsychological evaluation elsewhere, she reportedly failed effort measures with details unavailable, and her scores on finger tapping and grip strength were not consistent with a traumatic brain injury that produced no neurological examination evidence of limb weakness, of dyscoordination, or with a person who continued to live independently. In the neuropsychological examination by the first author, she again failed measures of effort. Her speech and language in the examination and in her deposition was much worse than when she spoke the same day as the examination on the telephone.

Superficially, the lack of fluency of Case 1 was consistent with a nonfluent or Broca's aphasia. However, her intact writing was more consistent with a lesion in Broca's area than with Broca's aphasia (Mohr, 1976). Lesions that cause Broca's aphasia or the speech deficits described by Mohr are large enough to be demonstrated by neuroimaging (Festa, Lazar, & Marshall, 2008); her neuroimaging was normal. Furthermore, they do not develop progressively; they begin suddenly and resolve (Festa et al., 2008). Her language constructions were childish, a feature said to be consistent with malingering (Baumgartner, 1999; Duffy, 2001). Multiple examiners characterized her language as psychogenic.

The speech abnormalities of Cases 2 and 3 were less blatant than the language abnormalities of Case 1. Case 2 sustained a possible mTBI with reported brief loss of consciousness. He had waxing and waning speech abnormalities that disappeared under time pressure, stress, or affective demand; conditions that perhaps would typically exacerbate genuine fluency disorders, such as when he became angry (Seery, 2005). However, the literature does not provide a clear guide regarding the diagnostic value of these types of inconsistencies. Seery noted that the variability in dysfluency was not diagnostic of feigning, whereas Baumgartner (1999) commented extensively on the inconsistencies of psychogenic stuttering. Suspicion of a psychogenic origin for his speech disorder also arose because he was too consistent. When he stuttered, he repeated the first sound in a given word, typically the first word in a sentence or phrase, but sometimes every word in a short sentence, exactly three times.

Case 3 had progressive onset of speech problems after her possible mild concussion. During neuropsychological evaluation, her speech abnormalities were inconsistent, and her complaints of additional neurocognitive impairments were dramatic and improbable.

The speech and language pathology literature includes the discussion of features that distinguish neurogenic and psychogenic speech and language disorders, including the aphasias and dysfluencies such as stuttering (Baumgartner, 1999; Helm-Estabrooks & Hotz, 1998). Baumgartner estimated that onset coinciding with head injury was associated about equally with neurogenic and psychogenic causation, but he did not categorize head injury by severity when providing this estimate. According to Baumgartner, particular types of inconsistencies may mark psychogenic causation of stuttering. Stuttering, in his view, is much more likely to be psychogenic if there are marked situational inconsistencies including periods of time with no stuttering, marked differences between conversation and reading, and worsening of stuttering when performing less-difficult tasks. Neurogenic stutterers are inconsistent in a different way; they do not stutter on every word or syllable.

Bizarre movements accompanying stuttering typically imply a psychogenic etiology; neurogenic stuttering is not characterized by facial grimacing, eye blinking, head bobbing, tremor, or fist clenching, except in hyperkinetic dysarthria found in disorders of the basal ganglia associated with other movement disorders such as choreoathetosis (http://www.csuchico.edu/~pmccaffrey//syllabi/SPPA342/342unit12.html). If there is no evidence of nonfluent aphasia, then telegraphic or agrammatic speech strongly suggests psychogenicity (Baumgartner, 1999). Aphasia is characterized by problems with all language modalities to some degree, including reading, writing, and oral speech comprehension and expression; someone who only has telegraphic or agrammatic speech with no problems in another language modality does not have nonfluent aphasia and likely has a psychogenic disorder. Bizarre speech, such as multiple repetitions of all phonemes accompanied by bizarre movements and childish or unusual grammatical constructions, for example, “me got sick,” are typical of psychogenic disorders (Baumgartner, 1999; Duffy, 2001). In general, marked improvement or resolution of symptoms following disclosure of emotionally laden material or after only a few sessions of treatment suggests a psychogenic cause (Baumgartner, 1999).

Stuttering acquired in adulthood clearly can be psychogenic, and criteria for distinguishing between neurogenic and psychogenic stuttering have been proposed (Baumgartner, 1999; Helm-Estabrooks & Hotz, 1998), but some features overlap (Seery, 2005). Stuttering is likely to be psychogenic if it does not improve in situations that usually improve fluency such as speaking or singing in unison or when performing overlearned recitation tasks such as the days of the week or counting. A study of seizure patients who received definitive diagnoses after undergoing intensive EEG monitoring indicated that stuttering during seizures was consistent with psychogenic causation and was not epileptogenic (Vossler et al., 2004). However, it is difficult to obtain a series of head-injured persons of sufficient size to validate the diagnostic accuracy of any formal diagnostic criteria for distinguishing between psychogenic and neurogenic speech and language disorders. The criteria described by speech and language experts (Baumgartner, 1999; Helm-Estabrooks & Hotz, 1998; Seery, 2005) are in the evidentiary category of anecdotal wisdom and lack sufficient diagnostic specificity to allow us to conclude with scientific certainty that the speech and language abnormalities of Cases 2 and 3 were of psychogenic origin. The neuropsychological test evidence of poor effort, coupled with the historical features, was critical to our conclusions that the speech and language abnormalities of our cases were of psychogenic origin. In our series, Case 1 probably had the most blatant language and articulation abnormalities.

This case series illustrates the value of neuropsychological testing for providing evidence malingering and poor effort. All cases showed evidence of suboptimal motivation on multiple measures. The evidence of poor effort for Cases 1 and 2 was overwhelming. Case 1 had extremely low scores in an examination prior to the first author's evaluation, for example, Finger Tapping scores on each hand of 8 and grip strength scores of 1.5 and 3.5 kg, despite demonstrating no motor deficits in neurological examinations. In the first author's examination, she had Finger Tapping scores of 5 and 4, grip strength of 1 and 0 kg on each hand, and she made large numbers of errors on tests of tactile sensation. These sensorimotor scores were inconsistent with normal abilities to manipulate test materials and open doors. She failed the TOMM by a wide margin. Her passing score on the PDRT do not negate the large number of failures on measures of effort, considering the imperfect sensitivities of any effort test, including the PDRT (Greve & Bianchini, 2006). Case 2 failed a total of five effort tests and embedded measures of effort, making poor effort or malingering highly likely. Of the three cases, Case 3 had the least amount of neuropsychological test evidence of poor effort. In her examination with the author, she failed Reliable Digit Span, WMT Immediate Recognition, and the PDRT hard items. In a prior examination, she had failed the PDRT but no score was available. For Case 3, we calculated the odds of poor effort to be 0.99, based on chaining the likelihood ratios of three failed effort tests (Larrabee, 2012). All cases had substantial external incentives for poor performance and two or more types of evidence of poor effort on testing. Failure on multiple measures of effort, including embedded measures and symptom validity tests, increases the probability of malingering (Larrabee, 2012).

These cases suggest that the presence of fluency impairment severe enough to be noticed in conversation following uncomplicated mTBI should alert the clinician to assess motivation and to carefully account for financial, psychosocial, or psychiatric issues related to symptom maintenance. We distinguish here between conversational fluency abnormalities noted in this case series and the more common abnormalities demonstrated by timed measures of fluency.

Future research should look at the speech patterns in naïve subjects given general instructions to feign fluency deficits. We predict that the speech of simulators will resemble the fluency patterns observed in our cases. It would also be of interest to learn if clinicians performing blind analyses of speech and language samples could accurately distinguish neurogenic cases such as aphasia caused by left hemisphere strokes from psychogenic language abnormalities. The performance on effort measures could be contrasted in samples of mTBI cases with and without similar speech and language abnormalities.

Conflict of Interest

The authors perform medicolegal evaluations.

References

Albers
J. W.
Schiffer
R.
Larrabee
G. J.
Features of the neurological evaluation that suggest noncredible performance
Assessment of malingered neuropsychological deficits
 , 
2007
New York
Oxford University Press
(pg. 
312
-
333
)
Arnold
G.
Boone
K. B.
Boone
K. B.
Use of motor and sensory tests as measures of effort
Assessment of feigned impairment. A neuropsychological perspective
 , 
2007
New York
Guilford
(pg. 
178
-
209
)
Axelrod
B. N.
Morgan
J. J.
Sweet
J. J.
Fabrication of psychiatric symptoms: Somatoform and psychotic disorders
Neuropsychology of malingering casebook
 , 
2009
New York
Psychology Press
(pg. 
180
-
194
)
Backhaus
S. L.
Fichtenberg
N. L.
Hanks
R. A.
Detection of sub-optimal performance using a floor effect strategy in patients with traumatic brain injury
The Clinical Neuropsychologist
 , 
2004
, vol. 
18
 (pg. 
591
-
603
)
Baumgartner
J. M.
Curlee
R. F.
Acquired psychogenic stuttering
Stuttering and related disorders of fluency
 , 
1999
2nd ed.
New York
Thieme Medical Publishers
(pg. 
269
-
288
)
Binder
L. M.
A review of mild head trauma. Part II: Clinical implications
Journal of Clinical and Experimental Neuropsychology
 , 
1997
, vol. 
19
 (pg. 
432
-
457
)
Binder
L. M.
Kelly
M. P.
Portland Digit Recognition Test performance by brain dysfunction patients without financial incentives
Assessment
 , 
1996
, vol. 
3
 (pg. 
403
-
409
)
Boone
K. B.
Salazar
X.
Lu
P.
Warner-Chacon
K.
Razani
J.
The Rey 15-item recognition trial: a technique to enhance sensitivity of the Rey 15-item memorization test
Journal of Clinical and Experimental Neuropsychology
 , 
2002
, vol. 
24
 (pg. 
561
-
573
)
Boone
K.
Lu
P.
Herzberg
D.
Dot counting test manual
 , 
2003
Los Angeles
Western Psychological Services
Boone
K. B.
Assessment of feigned cognitive impairment: A neuropsychological perspective
 , 
2007
New York
Guilford
Cottingham
M. E.
Boone
K. B.
Non-credible language deficits following mild traumatic brain injury
The Clinical Neuropsychologist
 , 
2010
, vol. 
25
 (pg. 
1006
-
1025
)
Dikmen
S. S.
Machamer
J. E.
Winn
H. R.
Temkin
N. R.
Neuropsychological outcome at 1-year post head injury
Neuropsychology
 , 
1995
, vol. 
9
 (pg. 
80
-
90
)
Duff
M. C.
Proctor
A.
Haley
K.
Mild traumatic brain injury (MTBI): Assessment and treatment protocols used by speech-language pathologists (SLPs)
Brain Injury
 , 
2002
, vol. 
16
 (pg. 
783
-
797
)
Duffy
J. R.
Psychogenic speech disorders in people with possible neurologic disease
 , 
2001
 
Telerounds 60, presented by the National Center for Neurogenic Communication Disorders
Festa
J. R.
Lazar
R. M.
Marshall
R. S.
Morgan
J. E.
Ricker
J. H.
Ischemic stroke and aphasic disorders
Textbook of clinical neuropsychology
 , 
2008
New York
Taylor & Francis
(pg. 
363
-
383
)
Gervais
R.O.
Ben-Porath
Y. S.
Wygant
D. B.
Empirical correlates and interpretation of the MMPI-2-RF Cognitive Complaints Scale
The Clinical Neuropsychologist
 , 
2009
, vol. 
23
 (pg. 
996
-
1015
)
Greiffenstein
M. F.
Larrabee
G. J.
Motor, sensory, and perceptual-motor pseudoabnormalities
Assessment of malingered neuropsychological deficits
 , 
2007
New York
Oxford University Press
(pg. 
100
-
130
)
Greiffenstein
M. F.
Baker
W. J.
Miller was (mostly) right: Head injury severity inversely related to simulation
Legal and Criminological Psychology
 , 
2006
, vol. 
11
 (pg. 
131
-
145
)
Greiffenstein
M. F.
Baker
W. J.
Gola
T.
Motor dysfunction profiles in traumatic brain injury and postconcussion syndrome
Journal of the International Neuropsychological Society
 , 
1996
, vol. 
2
 (pg. 
477
-
485
)
Greve
K. W.
Bianchini
K. J.
Classification accuracy of the Portland Digit Recognition Test in traumatic brain injury: Results of a known-group analysis
The Clinical Neuropsychologist
 , 
2006
, vol. 
20
 (pg. 
816
-
830
)
Greve
K. W.
Ord
J.
Curtis
K. L.
Bianchini
K. J.
Brennan
A.
Detecting malingering in traumatic brain injury and chronic pain: A comparison of three forced-choice symptom validity tests
The Clinical Neuropsychologist
 , 
2008
, vol. 
22
 (pg. 
896
-
918
)
Helm-Estabrooks
N.
Hotz
G.
Sudden onset of “stuttering“ in an adult: Neurogenic or psychogenic?
Seminars in Speech and Language
 , 
1998
, vol. 
19
 (pg. 
23
-
29
)
Jasiski
L. J.
Berry
D. T. R.
Shandera
A. L.
Clark
J. A.
Use of the Wechsler Adult Intelligence Scale Digit Span subtest for malingering detection: A meta-analytic review
Journal of Clinical and Experimental Neuropsychology
 , 
2011
, vol. 
33
 (pg. 
300
-
314
)
Larrabee
G. J.
Detection of malingering using atypical performance patterns on standard neuropsychological tests
The Clinical Neuropsychologist
 , 
2003
, vol. 
17
 (pg. 
410
-
425
)
Larrabee
G. J.
Assessment of malingered neuropsychological deficits
 , 
2007
New York
Oxford University Press
Larrabee
G. J.
Larrabee
G. J.
Assessment of malingering
Forensic neuropsychology. A scientific approach
 , 
2012
2nd ed.
New York
Oxford University Press
(pg. 
116
-
159
)
Lu
P.
Rogers
S. A.
Boone
K. B.
Boone
K. B.
Use of standard memory tests to detect suspect effort
Assessment of feigned impairment. A neuropsychological perspective
 , 
2007
New York
Guilford
(pg. 
128
-
151
)
McCrea
M. A.
Mild traumatic brain injury and postconcussion syndrome: The new evidence base for diagnosis and treatment
 , 
2008
New York
Oxford University Press
Mohr
J. P.
Whitaker
H.
Whitaker
H. A.
Broca's area and Broca's aphasia
Studies in neurolinguistics
 , 
1976
New York
Academic Press
(pg. 
201
-
235
)
Moore
D. P.
Textbook of clinical neuropsychiatry
 , 
2001
London
Arnold
National Center for Injury Prevention and Control
Report to congress on mild traumatic brain injury in the United States: Steps to prevent a serious public health problem
 , 
2003
Atlanta, GA
Centers for Disease Control and Prevention
Parrish
C.
Roth
C.
Roberts
B.
Davie
G.
Assessment of cognitive-communicative disorders of mild traumatic brain injury sustained in combat
Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders
 , 
2009
, vol. 
19
 (pg. 
47
-
57
)
Rohling
M. L.
Larrabee
G. J.
Millis
S. R.
The “miserable minority” following mild traumatic brain injury. Who are they and do meta-analyses hide them?
The Clinical Neuropsychologist
 , 
2012
, vol. 
26
 (pg. 
197
-
213
)
Seery
C. H.
Differential diagnosis of stuttering for forensic purposes
American Journal of Speech-Language Pathology
 , 
2005
, vol. 
14
 (pg. 
284
-
297
)
Thomas
M. L.
Youngjohn
J. R.
Let's not get hysterical: Comparing the MMPI-2 validity, clinical, and RC scales in TBI litigants tested for effort
The Clinical Neuropsychologist
 , 
2009
, vol. 
23
 (pg. 
1067
-
1084
)
Vossler
D. G.
Haltiner
A. M.
Schepp
S. K.
Friel
P. A.
Caylor
L. M.
Morgan
J. D.
, et al.  . 
Ictal stuttering: A sign suggestive of psychogenic nonepileptic seizures
Neurology
 , 
2004
, vol. 
63
 (pg. 
516
-
519
)
Youngjohn
J. R.
Burrows
L.
Erdal
K.
Brain damage or compensation neurosis? The controversial post-concussion syndrome
The Clinical Neuropsychologist
 , 
1995
, vol. 
9
 (pg. 
112
-
123
)
Youngjohn
J. R.
Lees-Haley
P. R.
Binder
L. M.
Comment: Warning malingerers produces more sophisticated malingering
Archives of Clinical Neuropsychology
 , 
1999
, vol. 
14
 (pg. 
511
-
515
)
Youngjohn
J. R.
Wershba
R.
Stevenson
M.
Sturgeon
J.
Thomas
M. L.
Independent validation of the MMPI-2-RF Somatic/Cognitive and Validity Scales in TBI litigants tested for effort
The Clinical Neuropsychologist
 , 
2011
, vol. 
25
 (pg. 
463
-
476
)