Abstract

The present study compared the performance of English- and Spanish-speaking healthy controls (HCs) on the Spanish translation of the Dementia Rating Scale-Second edition (ST-DRS-2) and examined the classification accuracy of the ST-DRS-2 and Mini-Mental State Examination (MMSE) with an age- and education-matched clinical sample. In contrast to previous findings with English-speakers, a stronger relationship was observed between ST-DRS-2 Total scores and education than with age, and despite being matched on both of these variables, English-speaking HCs significantly out-performed their Spanish-speaking counterparts on the ST-DRS-2. The greatest between-group difference was found on the Memory subscale, wherein the majority of errors committed by Spanish-speaking HCs were significantly related to level of acculturation. ST-DRS-2 Total and Memory subscale scores produced greater classification accuracy than the MMSE; however, ST-DRS-2 Total scores yielded the greatest corresponding rates of sensitivity and specificity. Normative data are provided and recommended to improve the ST-DRS-2's diagnostic accuracy with Spanish-speakers.

Introduction

With the average life expectancy consistently increasing, the population of older adults in the USA has grown considerably, and with it, the need for empirically validated diagnostic instruments and subsequent treatment methods to address the medical problems primarily associated with advanced age (Strauss, Sherman, & Spreen, 2006). Dementia is one such condition, which is estimated to afflict between 5% and 10% of the population over 65 years of age, and approximately half of the population 85 years and older (Alzheimer's Association, 2010). With numerous etiologies producing disparate cognitive deficits and rates of progression, which may result in various behavioral manifestations, the accurate assessment of dementing conditions is often a formidable task (Crigger & Forbes, 1997; Maynard, 2003). To facilitate this endeavor, the Dementia Rating Scale (DRS) was developed by Coblentz and colleagues (1973), and published for professional use by Mattis (1988), as a screening instrument for patients with dementing illnesses. Since the inception of this measure in 1973, research has documented the excellent psychometric properties of the DRS (Bobholz & Brandt, 1993; Brown et al., 1999; Smith et al., 1994), as well as the significant relationship of age and education to DRS performance (Lucas et al., 1998; Marcopulos, Gripshover, Broshek, McLain, & Brashear, 1999). In response to these findings, Jurica, Leitten, and Mattis (2001) published an updated manual of the original instrument—the DRS-Second edition (DRS-2)—which includes age-stratified normative data derived from a larger sample for both total and subscale scores, as well as subsequent total score corrections for different levels of education.

While such improvements have augmented the diagnostic accuracy of this instrument with the sample upon which these norms were derived (i.e., predominantly well-educated English-speaking Caucasian older adults), the clinical utility of the DRS-2 remains limited as considerable discrepancies in performance continue to be observed between the published norms and samples of disparate ethnicities matched on age, education, and cognitive status (Chan, Choi, & Salmon, 2001; Jervis, Beals, Fickenscher, & Arciniegas, 2007; Lyness, Hernandez, Chui, & Teng, 2006). Although race is not considered a significant predictor of performance on this measure, the few studies that have utilized this instrument with populations other than well-educated Caucasian samples have found significant cultural influences on DRS-2 performance, particularly in Spanish-speaking populations (Arnold, Cuellar, & Guzman, 1998; Hohl, Grundman, Salmon, Thomas, & Thal, 1999; Lyness et al., 2006). For instance, research by Arnold and colleagues (1998) revealed that the original English norms for the DRS produced a false-positive rate of 56% in their sample of non-impaired Spanish-speaking elders. Subsequent studies confirming this discrepancy found that in addition to DRS Total scores, Hispanic participants scored lower than their non-Hispanic counterparts, specifically on the subscales of Memory and Conceptualization (Hohl et al., 1999), as well as Attention (Lyness et al., 2006).

Recognizing the risk of substantial diagnostic error, attempts were made to produce appropriate normative data for various Spanish translations of this screening instrument. The most superlative of these was derived by Lyness and colleagues (2006) from a sample of 54 Spanish-speaking healthy controls (HCs) on a previously validated Spanish version of the DRS (Arnold et al., 1998; Mattis, 1973). Stratified by age, as well as education, and encompassing a broader range of demographic variability (e.g., education levels between 1 and 20 years, a variety of countries of origin, bilingual and monolingual Spanish-speakers, etc.), these norms constitute a significant advancement in the accurate assessment of Spanish-speaking older adults in the USA. However, considering that the Lyness and colleagues (2006) study was based on a small sample and little consideration was given to the multitude of socio-demographic characteristics responsible for within-group differences, further research is needed to replicate these findings and to investigate the potential sources of variation within such groups.

Although joined by a common language, the U.S. Spanish-speaking community is an incredibly heterogeneous group representing the socioeconomic, cultural, educational, and linguistic backgrounds of more than 20 different Spanish-speaking countries dispersed across three continents (Gasquoine, 2009). Further diversifying this population are the various levels of acculturation resulting from the number of residency years in the USA and the degree of interaction with the dominant culture (Acevedo, Loewenstein, Agrón, & Duara, 2007; Gasquoine, 2009). As Gasquoine (2009) suggests, culture and ethnicity are not discrete entities, but rather continuous variables, which when conceived as such, do not aid the comprehension of variation in neuropsychological test performance. Therefore, in order to ascertain the etiology of the discrepancy between Hispanic and non-Hispanic neuropsychological test scores and ultimately increase the diagnostic accuracy of assessment measures with minority populations, researchers must conceptualize culture and ethnicity as quantitative psychological dimensions along which these groups may differ (e.g., English/Spanish fluency, level of acculturation, etc.: Gasquoine, 2009; Phinney, 1996).

The purpose of the present study was to advance the establishment of appropriate norms and thereby improve the use of the Spanish translation of the DRS-2 (ST-DRS-2) as a neurocognitive screening tool for the Spanish-speaking community of the USA by: (a) examining the extent to which socio-demographic characteristics of Spanish-speaking HCs influence performance on the ST-DRS-2; (b) investigating the performance discrepancy between Spanish-speaking versus English-speaking HCs on this measure; and (c) comparing the diagnostic classification accuracy of the ST-DRS-2 Total and ST-DRS-2 Memory subscale scores with that of a brief cognitive screening instrument (i.e., Mini-Mental State Examination, MMSE) in a sample of Spanish-speaking dementia patients and a subsample of age- and education-matched Spanish-speaking HCs.

Method

Participants

Spanish-speaking HCs

One hundred fifty-seven monolingual Spanish-speaking, cognitively-intact older adults were included in the present study. All these individuals were community volunteers, ages 50–80, recruited for a comprehensive neuropsychological norming study at Baylor College of Medicine in Houston, TX. Potential participants were screened to exclude those with a history of neurological (e.g., head trauma, stroke, tumor, seizures, congenital abnormalities, and transient ischemic attacks) or psychiatric disorders that could interfere with testing (e.g., severe depression, schizophrenia, etc.). This study was approved by Baylor College of Medicine's Institutional Review Board. All community volunteers provided informed consent and were compensated for their participation.

Spanish-speaking dementia patients

Data for 60 Spanish-speaking dementia patients (meeting diagnostic and statistical manual 4th edition text revised diagnostic criteria and based on consensus) were collected via chart reviews conducted at Baylor College of Medicine in Houston, TX, and at the University of Puerto Rico Medical Sciences Campus in San Juan, PR. The mean age of this group was 65.3 (8.2) and 51.7% were men. Their average level of education was 13.6 (3.8) years. These patients underwent the standard clinical neuropsychological evaluations in which the ST-DRS-2 had been utilized as a screening tool.

Non-Hispanic English-speaking HC comparison group

The neuropsychological data of 30 primarily English-speaking, cognitively-intact older adults were employed in the current study for comparison with an age- and education-matched subsample of the aforementioned Spanish-speaking HCs. These data were collected as part of a separate study approved by Baylor College of Medicine's IRB. Participants were community volunteers and the same exclusion criteria were used as described above for the Spanish-speaking HC group.

Procedures

The Expressive Vocabulary Test (Williams, 1997) and the Marin Acculturation Scale (MAS; Marin, Sabogal, Marin, Otero-Sabogal, & Perez-Stable, 1987) were utilized to verify the linguistic status of each Spanish-speaking participant. These individuals were also administered a Spanish version of the MMSE (words used: papel, bicicleta, and cuchara; sentence: Ni no, ni si, and ni pero; no backward spelling) (Folstein, Folstein, & McHugh, 1975), Beck Anxiety Inventory (Beck, 1993), Beck Depression Inventory-II (Beck, Steer, & Brown, 1996), and the author and publisher's authorized literal ST-DRS-2 (Strutt, 2011). The ST-DRS-2 was translated and back translated by Dr. Strutt and her laboratory. Given the simplistic nature of the language used in this measure, the process of a literal translation did not encounter many discrepancies across reviewers of the work. The translation and back translation was then submitted to several Spanish-speaking neuropsychologists, to the authors of the original DRS-2 and to the publishing company (PAR) for review. The translation was approved by the authors and the publishing company, and the normative data provided in this study are for this approved version of the ST-DRS-2 which is available through the publishing company. The English-speaking comparison group received the English versions of the aforementioned instruments. All neuropsychological measures were administered and scored according to the standardized procedures, and statistical analyses were conducted using IBM SPSS version 19.0.

Results

The current sample of Spanish-speaking HCs consisted of 60 (38.2%) men and 97 (61.8%) women, who ranged in age from 50 to 80, with 6–19 years of education. The majority of participants were right-handed (91%) and despite a mean of 21.2 years in the USA, all participants reported low-to-moderate levels of acculturation. Participants originated from 15 countries of Central and South America, including: Mexico (39.4%), Argentina (10.3%), El Salvador (9.03%), Colombia (7.74%), Nicaragua (5.20%), Venezuela (4.52%), Puerto Rico (3.87%), Guatemala (3.87%), Peru (3.23%), Honduras (3.23%), Ecuador (2.58%), Chile (2.58%), Uruguay (1.94%), Dominican Republic (1.29%), and Cuba (1.29%). The clinical classifications of self-reported anxiety symptoms were as follows: 48.3% minimal, 35.1% mild, 10.6% moderate, and 6.0% severe. Additionally, the clinical classifications of depressive symptoms were reported as: 62.8% minimal, 26.3% mild, 9.0% moderate, and 1.9% severe.

No significant differences were found between male and female Spanish-speaking HCs on any demographic variable or on the outcome measure. However, women in this sample obtained significantly lower scores on a measure of general cognitive status—MMSE: t(151) = 2.26, p = .03—and reported significantly greater symptoms of anxiety (χ2= 10.1, p = .02) and depression (χ2= 10.3, p = .02) than men. For the total sample of Spanish-speaking HCs, a stronger relationship was observed between ST-DRS-2 Total scores and education (r = .40, p < .001) than with age (r = −.21, p = .008). Moreover, level of acculturation (MAS) was significantly correlated with education (r = .25, p = .002) and ST-DRS-2 Total score (r = .17, p = .04), as well as two subscales of this measure (Attention: r = .19, p = .02; Initiation/Perseveration: r = .17, p = .04). The relationship between education and acculturation on the ST-DRS-2 Total score was further examined using linear regression. Acculturation only accounted for 2.6% of the variance, while education accounted for 15.6%. For the socio-demographic characteristics, ST-DRS-2 scores, and variable correlations for Spanish-speaking HCs, refer to Table 1.

Table 1.

Socio-demographic characteristics, ST-DRS-2 raw scores, and variable correlations for total sample of Spanish-speaking HCs

 Mean (SDEducation Gender Years in USA MAS MMSE ST-DRS-2
 
       AT IP CT CP ME TS 
Age 61.7 (7.68) −.02 .05 .29*** −.02 −.26** −.17* −.02 .01 −.22** −.22** −.21** 
Education 11.8 (3.65)  −.08 −.14 .25** .30*** .29*** .16* −.03 .42*** .22** .40*** 
Gender (% men) 60 (38.2%)   −.06 .05 −.18* −.10 −.09 .09 −.12 −.06 −.13 
Years in USA 21.2 (15.5)    .06 −.14 −.04 .003 −.21* −.06 .09 −.03 
Acculturation level (MAS) 20.3 (4.98)     .13 .19* .17* .07 .05 .06 .17* 
MMSE 25.8 (2.42)      .46*** .09 .07 .28*** .30*** .37*** 
ST-DRS-2 
 AT 35.5 (1.58)       .21** −.04 .21** .27*** .52*** 
 IP 35.8 (2.72)        .04 .39*** .28*** .76*** 
 CT 5.90 (0.34)         −.08 −.12 −.01 
 CP 35.5 (2.83)          .35*** .78*** 
 ME 22.3 (1.56)           .61*** 
 TS 135 (6.06)            
 Mean (SDEducation Gender Years in USA MAS MMSE ST-DRS-2
 
       AT IP CT CP ME TS 
Age 61.7 (7.68) −.02 .05 .29*** −.02 −.26** −.17* −.02 .01 −.22** −.22** −.21** 
Education 11.8 (3.65)  −.08 −.14 .25** .30*** .29*** .16* −.03 .42*** .22** .40*** 
Gender (% men) 60 (38.2%)   −.06 .05 −.18* −.10 −.09 .09 −.12 −.06 −.13 
Years in USA 21.2 (15.5)    .06 −.14 −.04 .003 −.21* −.06 .09 −.03 
Acculturation level (MAS) 20.3 (4.98)     .13 .19* .17* .07 .05 .06 .17* 
MMSE 25.8 (2.42)      .46*** .09 .07 .28*** .30*** .37*** 
ST-DRS-2 
 AT 35.5 (1.58)       .21** −.04 .21** .27*** .52*** 
 IP 35.8 (2.72)        .04 .39*** .28*** .76*** 
 CT 5.90 (0.34)         −.08 −.12 −.01 
 CP 35.5 (2.83)          .35*** .78*** 
 ME 22.3 (1.56)           .61*** 
 TS 135 (6.06)            

Notes: MAS = Marin Acculturation Scale; MMSE = Mini-Mental State Exam; AT = Attention; IP = Initiation/Perseveration; CT = Construction; CP = Conceptualization; ME = Memory; TS = Total Score; ST-DRS-2 = Spanish translation of the Dementia Rating Scale-Second edition.

*p< .05.

**p< .01.

***p< .001.

Comparison between Spanish- and English-speaking HCs on the outcome measure

The comparison between English-speaking HCs and an age- and education-matched subsample of Spanish-speaking HCs on demographic characteristics and DRS-2 scores (ST-DRS-2 scores for Spanish speakers and DRS-2 scores for English speakers) are provided in Table 2. As shown, no significant differences were observed between these groups for age, education, or gender. However, English-speaking HCs significantly out-performed their Spanish-speaking counterparts on the DRS-2 Total and subscale scores, except for the Construction subscale, which only showed a significant trend between groups. Only one (3.33%) participant from each group was misclassified as impaired with the age-corrected scale scores derived from the original normative data. Alternatively, three (10.0%) Spanish-speaking participants and only one (3.33%) English-speaking participant were misclassified as impaired when the age-adjusted scale scores were also corrected for education. The three misclassified Spanish-speaking participants had a college level of education. Thus, it appears that this correction is over-adjusting test scores for individuals with higher levels of schooling, thereby increasing the number of false-positive errors in regard to impairment classifications. In addition, the inter-correlations among the demographic variables and the Total and subscale scores of the outcome measure varied between the two language groups. These relationships are demonstrated in Table 3.

Table 2.

Comparison between Spanish- and English-speaking age- and education-matched HCs on demographic characteristics and the ST-DRS-2/DRS-2 Total and subscale raw scores

 Spanish HCs (n = 30)
 
English HCs (n = 30)
 
t/χ2 p-value 
 Mean (SDRange Mean (SDRange   
Age 64.9 (8.76) 50–79 63.2 (12.2) 31–85 −0.62 .54 
Education 15.1 (1.93) 7–19 15.6 (2.47) 7–18 0.87 .39 
Gender (% men) 15 (50.0%) — 11 (36.7%) — 1.09 .30 
ST-DRS-2/DRS-2 
 Attention 35.2 (1.87) 31–37 36.2 (1.22) 32–37 2.26 .03 
 Initiation/Perseveration 35.8 (1.74) 29–37 36.6 (0.87) 34–37 2.21 .03 
 Construction 5.83 (0.46) 4–6 6.00 (0.00) 1.91 .06 
 Conceptualization 36.5 (1.85) 33–39 37.6 (1.91) 31–39 2.17 .04 
 Memory 22.2 (2.01) 14–25 23.8 (2.87) 10–25 2.40 .02 
 Total Score 136 (4.82) 122–143 140 (4.20) 125–144 3.79 <.001 
 Spanish HCs (n = 30)
 
English HCs (n = 30)
 
t/χ2 p-value 
 Mean (SDRange Mean (SDRange   
Age 64.9 (8.76) 50–79 63.2 (12.2) 31–85 −0.62 .54 
Education 15.1 (1.93) 7–19 15.6 (2.47) 7–18 0.87 .39 
Gender (% men) 15 (50.0%) — 11 (36.7%) — 1.09 .30 
ST-DRS-2/DRS-2 
 Attention 35.2 (1.87) 31–37 36.2 (1.22) 32–37 2.26 .03 
 Initiation/Perseveration 35.8 (1.74) 29–37 36.6 (0.87) 34–37 2.21 .03 
 Construction 5.83 (0.46) 4–6 6.00 (0.00) 1.91 .06 
 Conceptualization 36.5 (1.85) 33–39 37.6 (1.91) 31–39 2.17 .04 
 Memory 22.2 (2.01) 14–25 23.8 (2.87) 10–25 2.40 .02 
 Total Score 136 (4.82) 122–143 140 (4.20) 125–144 3.79 <.001 

Notes: ST-DRS-2 = Spanish translation of the Dementia Rating Scale-Second edition; DRS-2 = Original English version of the Dementia; HC = healthy control.

Table 3.

Comparison of demographic variables and ST-DRS-2/DRS-2 Total and subscale raw score correlations between Spanish- and English-speaking age- and education-matched HCs

 Education Gender ST-DRS-2/DRS-2
 
   AT IP CT CP ME TS 
Spanish-speaking HCs (n = 30) 
 Age −.02 −.11 −.12 .09 −.27 −.12 −.03 −.09 
 Education  −.27 .47** .42* −.22 .37* .41* .62*** 
 Gender   −.09 −.16 .33 −.13 −.12 −.16 
 ST-DRS-2 
  AT    .23 −.19 .16 .38* .68*** 
  IP     .14 .36 −.03 .59** 
  CT      −.18 −.25 −.12 
  CP       .29 .68*** 
  ME        .65*** 
  TS        — 
English-speaking HCs (n = 30) 
 Age .39* −.04 −.25 −.48** a −.19 −.19 −.39* 
 Education  .04 .18 −.1 a −.13 −.03 −.05 
 Gender   .02 .11 a −.14 −.07 −.08 
 DRS-2 
  AT    .06 a .43* .19 .63*** 
  IP     a −.16 .19 .28 
  CT      a a a 
  CP       −.04 .52** 
  ME        .76*** 
  TS        — 
 Education Gender ST-DRS-2/DRS-2
 
   AT IP CT CP ME TS 
Spanish-speaking HCs (n = 30) 
 Age −.02 −.11 −.12 .09 −.27 −.12 −.03 −.09 
 Education  −.27 .47** .42* −.22 .37* .41* .62*** 
 Gender   −.09 −.16 .33 −.13 −.12 −.16 
 ST-DRS-2 
  AT    .23 −.19 .16 .38* .68*** 
  IP     .14 .36 −.03 .59** 
  CT      −.18 −.25 −.12 
  CP       .29 .68*** 
  ME        .65*** 
  TS        — 
English-speaking HCs (n = 30) 
 Age .39* −.04 −.25 −.48** a −.19 −.19 −.39* 
 Education  .04 .18 −.1 a −.13 −.03 −.05 
 Gender   .02 .11 a −.14 −.07 −.08 
 DRS-2 
  AT    .06 a .43* .19 .63*** 
  IP     a −.16 .19 .28 
  CT      a a a 
  CP       −.04 .52** 
  ME        .76*** 
  TS        — 

Notes: AT = Attention; IP = Initiation/Perseveration; CT = Construction; CP = Conceptualization; ME = Memory; TS = Total Score; ST-DRS-2 = Spanish translation of the Dementia Rating Scale-Second edition; DRS-2 = Original English version of the Dementia Rating Scale-Second edition.

aCorrelation cannot be computed because one of the variables is a constant.

*p< .05.

**p <.01.

***p< .001.

While the Spanish-speaking subsample demonstrated a limited range of scores on the Construction subscale (4–6), no variability was seen on this subscale in the English-speaking HC group, as all participants obtained perfect scores. Additionally, the greatest difference observed between Spanish- and English-speaking HCs was evidenced on the Memory subscale, wherein 17 (56.7%) English-speaking HCs and only 1 (3.33%) Spanish-speaking HC obtained perfect scores. Similar results were observed for ST-DRS-2 Memory subscale scores for the total sample of Spanish-speaking HCs, with only four (2.55%) participants obtaining perfect scores. However, upon further examination of Spanish-speaking HCs' performance on this subscale, it was discovered that the vast majority of errors were committed on three specific items requiring examinees to provide the full name of U.S. government officials, including the current president (25.2%), governor (81.1%), and mayor (77.6%). Thus, the frequency of perfect scores on the ST-DRS-2 Memory subscale was significantly augmented for Spanish-speaking HCs (85 [59.4%]) with the omission of these three items, producing a rate comparable with that of the English-speaking group. Level of acculturation (MAS) was the only socio-demographic characteristic significantly correlated with orientation subtotals of the ST-DRS-2 Memory subscale (r = .79, p < .001) and was also identified as the only significant predictor of this variable—F(3, 156) = 83.6, p < .001; Age: β = 0.02, p = .77; Education: β = −0.01, p = .92; MAS: β = 0.79, p < .001. A comparison based on the level of acculturation between the English- and Spanish-speaking HCs was not possible as the majority of Spanish-speaking participants reported low levels of acculturation, even though the majority of them have been residents of the USA for many years.

Preliminary normative data for Spanish-speaking HCs

Utilizing a conservative approach with only those variables significantly correlated with the outcome measure at <.01, linear regression analyses identified both age (β = −0.20, p = .006) and education (β = 0.40, p < .001) as significant predictors of ST-DRS-2 Total scores—F(2, 156) = 19.4, p < 0.001. Given such findings, ST-DRS-2 Total and subscale score normative data were stratified by four education groups and are provided by decade (i.e., 50–59 years [n = 67], 60–69 years [n = 68], and 70–80 years [n = 22]) in Tables 4–6. These norms can be utilized to compare performance between English- and Spanish-speaking patients on the same metric. However, in an attempt to attenuate the influence of culture on the Memory and Total subscale scores of the ST-DRS-2, items requesting the patient to name the President, Governor, and Mayor were removed from the Memory subscale and subsequently the Total subscale score. Corrected normative data presented reflect the exclusion of these three items in Supplementary material online, Tables S4–S6.

Table 4.

ST-DRS-2 Total and subscale score normative data for 50–59-year olds by education group

 6
 
7–12
 
13–15
 
16–19
 
 Raw score T-score Raw score T-score Raw score T-score Raw score T-score 
Attention 
 Superior 37 63–66 — — — — — — 
 Above Average 36 59–60 37* 58–62 38* 57–59 38* 57 
 Average 34–35 44–53 35–36 47–54 36–37 46–55 36–37 47–56 
 Below Average — — 34 40–43 35 43 — — 
 Borderline 32 30 33 30–34 33 32–33 33 31 
 Deficient 31 26 32 29 32 — — — 
Initiation/Perseveration 
 Superior — — — — — — — — 
 Above Average 38* 59–60 38* 57–59 38* 57 — — 
 Average 35–37 50–55 36–37 44–56 35–37 48–55 36–37 44–56 
 Below Average 33 41 35 53 — — 35 40 
 Borderline 29 33 29 32 — — — — 
 Deficient — — 17 29–31 29 — — 
Construction 
 Superior — — — — — — — — 
 Above Average 7* 57–58 7* 57 — — — — 
 Average 56 53–56 50–53 49–52 
 Below Average 38 — — —  — — 
 Borderline — — 33–34 33 — — 
 Deficient 12 — — — — 
Conceptualization 
 Superior 39 69 39 64 — — — — 
 Above Average 37 61 38 57–63 39* 57–60 40* 57–58 
 Average 34–36 47–56 35–37 44–53 36–38 45–56 36–39 44–55 
 Below Average — — 33–34 39–40 35 42–43 35 40 
 Borderline 31 33 — — 33 34 34 35 
 Deficient — — 25–31 5–28 — — — — 
Memory 
 Superior — — — — 25 64–66 — — 
 Above Average 24 63 24* 58–60 24 57–60 24 57–59 
 Average 22–23 47–56 22–23 46–56 22–23* 45–56 23* 46–52 
 Below Average 21 42 21 41–43 21 37 22 43 
 Borderline 19 31 20 34 20 35 — — 
 Deficient — — 19 29 14 — — 
Total 
 Superior — — — — — — — — 
 Above Average 137–140 57–62 139–141 57–63 142–143* 57–59 142 57 
 Average 130–135 46–53 132–138* 45–56 134–141 44–56 137–141 46–55 
 Below Average — — 129–131 39–40 131–133 40–43 — — 
 Borderline 123 36 122 33 — — 130 34 
 Deficient 120 29 103 125 28 — — 
 6
 
7–12
 
13–15
 
16–19
 
 Raw score T-score Raw score T-score Raw score T-score Raw score T-score 
Attention 
 Superior 37 63–66 — — — — — — 
 Above Average 36 59–60 37* 58–62 38* 57–59 38* 57 
 Average 34–35 44–53 35–36 47–54 36–37 46–55 36–37 47–56 
 Below Average — — 34 40–43 35 43 — — 
 Borderline 32 30 33 30–34 33 32–33 33 31 
 Deficient 31 26 32 29 32 — — — 
Initiation/Perseveration 
 Superior — — — — — — — — 
 Above Average 38* 59–60 38* 57–59 38* 57 — — 
 Average 35–37 50–55 36–37 44–56 35–37 48–55 36–37 44–56 
 Below Average 33 41 35 53 — — 35 40 
 Borderline 29 33 29 32 — — — — 
 Deficient — — 17 29–31 29 — — 
Construction 
 Superior — — — — — — — — 
 Above Average 7* 57–58 7* 57 — — — — 
 Average 56 53–56 50–53 49–52 
 Below Average 38 — — —  — — 
 Borderline — — 33–34 33 — — 
 Deficient 12 — — — — 
Conceptualization 
 Superior 39 69 39 64 — — — — 
 Above Average 37 61 38 57–63 39* 57–60 40* 57–58 
 Average 34–36 47–56 35–37 44–53 36–38 45–56 36–39 44–55 
 Below Average — — 33–34 39–40 35 42–43 35 40 
 Borderline 31 33 — — 33 34 34 35 
 Deficient — — 25–31 5–28 — — — — 
Memory 
 Superior — — — — 25 64–66 — — 
 Above Average 24 63 24* 58–60 24 57–60 24 57–59 
 Average 22–23 47–56 22–23 46–56 22–23* 45–56 23* 46–52 
 Below Average 21 42 21 41–43 21 37 22 43 
 Borderline 19 31 20 34 20 35 — — 
 Deficient — — 19 29 14 — — 
Total 
 Superior — — — — — — — — 
 Above Average 137–140 57–62 139–141 57–63 142–143* 57–59 142 57 
 Average 130–135 46–53 132–138* 45–56 134–141 44–56 137–141 46–55 
 Below Average — — 129–131 39–40 131–133 40–43 — — 
 Borderline 123 36 122 33 — — 130 34 
 Deficient 120 29 103 125 28 — — 

Notes: Clinical classification t-score ranges are as follows: Superior > 63; Above Average = 57–63; Average = 44–56; Below Average = 37–43; Borderline = 30–36; Deficient ≤ 29.

*As the actual range of raw scores fell across two adjacent T-score ranges and given that the DRS-2 is a screening measure, the decision was made to error on the side of false positives, so the raw score was included in the lower T-score classification category.

Table 5.

ST-DRS-2 Total and subscale score normative data for 60–69-year olds by education group

 6
 
7–12
 
13–15
 
16–19
 
 Raw score T-score Raw score T-score Raw score T-score Raw score T-score 
Attention 
 Superior 37 66 — — — — — — 
 Above Average 36 57–63 37 57–61 38* 57–61 38* 57–58 
 Average 35 49–51 35–36 44–56 36–37 50–56 36–37 49–56 
 Below Average 34 43 34 40–43 34–35 37–43 35 42 
 Borderline 33 36 33 34–35 33 32 33 31 
 Deficient — — 30 12 32 25 — — 
Initiation/Perseveration 
 Superior — — — — — — — — 
 Above Average 37 57–61 38* 57–61 38* 57–61 38* 57–59 
 Average 36 48–49 35–37 46–55 35–37 45–56 35–37 45–55 
 Below Average 35 40–43 — — 34 38 — — 
 Borderline — — 33 30 — — 33 31 
 Deficient — — 31 16 30–33 9–29 — — 
Construction 
 Superior — — — — — — — — 
 Above Average — — — — — — — — 
 Average 49–52 49–54 51–55 52–55 
 Below Average — — — — — — — — 
 Borderline — — — — — — — — 
 Deficient 16 — — 18 
Conceptualization 
 Superior 37 64 39 66 39 65 — — 
 Above Average 36 60 37–38* 57–62 38* 57–61 39 62 
 Average 33–35 48–56 33–36 45–55 34–37 44–56 35–38 46–55 
 Below Average 31–32 40–43 32 41 33 40–41 34 42 
 Borderline 29–30 32–36 30–31* 30–36 — — — — 
 Deficient — — 29 27 — — 30–31 25–29 
Memory 
 Superior 24 65 25 73 25* 64 25* 64–72 
 Above Average 23 57–58 24* 57 24 63 24 63 
 Average 22 49–50 22–23 48–56 22–23 47–56 22–23 47–56 
 Below Average 21 41 21 40 21 39–40 21 39 
 Borderline 20 32 20 31–33 20 31 — — 
 Deficient — — — — — — — — 
Total 
 Superior — — 140* 64 142* 65–66 143 68–69 
 Above Average 135–138 58–63 139* 57–63 139–141* 58–62 141 60 
 Average 131–134 46–54 132–138 45–56 135–138* 45–54 135–138* 45–56 
 Below Average 129–130 39–41 130–131 38–43 131–134 38- 133–134 40–42 
 Borderline — — 128–129 34–36 128–129 30–32 — — 
 Deficient — — 126 27 127 28 — — 
 6
 
7–12
 
13–15
 
16–19
 
 Raw score T-score Raw score T-score Raw score T-score Raw score T-score 
Attention 
 Superior 37 66 — — — — — — 
 Above Average 36 57–63 37 57–61 38* 57–61 38* 57–58 
 Average 35 49–51 35–36 44–56 36–37 50–56 36–37 49–56 
 Below Average 34 43 34 40–43 34–35 37–43 35 42 
 Borderline 33 36 33 34–35 33 32 33 31 
 Deficient — — 30 12 32 25 — — 
Initiation/Perseveration 
 Superior — — — — — — — — 
 Above Average 37 57–61 38* 57–61 38* 57–61 38* 57–59 
 Average 36 48–49 35–37 46–55 35–37 45–56 35–37 45–55 
 Below Average 35 40–43 — — 34 38 — — 
 Borderline — — 33 30 — — 33 31 
 Deficient — — 31 16 30–33 9–29 — — 
Construction 
 Superior — — — — — — — — 
 Above Average — — — — — — — — 
 Average 49–52 49–54 51–55 52–55 
 Below Average — — — — — — — — 
 Borderline — — — — — — — — 
 Deficient 16 — — 18 
Conceptualization 
 Superior 37 64 39 66 39 65 — — 
 Above Average 36 60 37–38* 57–62 38* 57–61 39 62 
 Average 33–35 48–56 33–36 45–55 34–37 44–56 35–38 46–55 
 Below Average 31–32 40–43 32 41 33 40–41 34 42 
 Borderline 29–30 32–36 30–31* 30–36 — — — — 
 Deficient — — 29 27 — — 30–31 25–29 
Memory 
 Superior 24 65 25 73 25* 64 25* 64–72 
 Above Average 23 57–58 24* 57 24 63 24 63 
 Average 22 49–50 22–23 48–56 22–23 47–56 22–23 47–56 
 Below Average 21 41 21 40 21 39–40 21 39 
 Borderline 20 32 20 31–33 20 31 — — 
 Deficient — — — — — — — — 
Total 
 Superior — — 140* 64 142* 65–66 143 68–69 
 Above Average 135–138 58–63 139* 57–63 139–141* 58–62 141 60 
 Average 131–134 46–54 132–138 45–56 135–138* 45–54 135–138* 45–56 
 Below Average 129–130 39–41 130–131 38–43 131–134 38- 133–134 40–42 
 Borderline — — 128–129 34–36 128–129 30–32 — — 
 Deficient — — 126 27 127 28 — — 

Notes: Clinical classification t-score ranges are as follows: Superior > 63; Above Average = 57–63; Average = 44–56; Below Average = 37–43; Borderline = 30–36; Deficient ≤ 29.

*As the actual range of raw scores fell across two adjacent T-score ranges and given that the DRS-2 is a screening measure, the decision was made to error on the side of false positives, so the raw score was included in the lower T-score classification category.

Table 6.

ST-DRS-2 Total and subscale score normative data for 70–80-year olds by education group

 6–12
 
13–16
 
 Raw score T-score Raw score T-score 
Attention 
 Superior 38* 65 — — 
 Above Average 36–37 57–62 37 61 
 Average 34–35 49–55 35–36 50–55 
 Below Average 33 41–43 33 39–40 
 Borderline — — — — 
 Deficient — — 31 27 
Initiation/Perseveration 
 Superior — — — — 
 Above Average 37–38* 57–62 — — 
 Average 35–36 50–56 34–37 45–54 
 Below Average 32 42 — — 
 Borderline — — — — 
 Deficient 16 14 — — 
Construction 
 Superior — — — — 
 Above Average — — 7* 60 
 Average 46–54 54–56 
 Below Average — — — — 
 Borderline — — — — 
 Deficient — — 5* 28 
Conceptualization 
 Superior 37 71 — — 
 Above Average — — 38–39* 57–61 
 Average 28–35 44–52 35–37 46–53 
 Below Average 27 40–41 33–34 42 
 Borderline 26 36 — — 
 Deficient — — — — 
Memory 
 Superior — — — — 
 Above Average 24* 58–63 24 60 
 Average 20–23 47–53 23* 44–56 
 Below Average 18 42–43 21–22* 37–43 
 Borderline 16 33 20 35 
 Deficient — — — — 
Total 
 Superior 135–136 64–67 — — 
 Above Average 126 58 — — 
 Average 119–125* 45–56 133–139* 44–55 
 Below Average — — 130–132 40–43 
 Borderline — — — — 
 Deficient 98 20 — — 
 6–12
 
13–16
 
 Raw score T-score Raw score T-score 
Attention 
 Superior 38* 65 — — 
 Above Average 36–37 57–62 37 61 
 Average 34–35 49–55 35–36 50–55 
 Below Average 33 41–43 33 39–40 
 Borderline — — — — 
 Deficient — — 31 27 
Initiation/Perseveration 
 Superior — — — — 
 Above Average 37–38* 57–62 — — 
 Average 35–36 50–56 34–37 45–54 
 Below Average 32 42 — — 
 Borderline — — — — 
 Deficient 16 14 — — 
Construction 
 Superior — — — — 
 Above Average — — 7* 60 
 Average 46–54 54–56 
 Below Average — — — — 
 Borderline — — — — 
 Deficient — — 5* 28 
Conceptualization 
 Superior 37 71 — — 
 Above Average — — 38–39* 57–61 
 Average 28–35 44–52 35–37 46–53 
 Below Average 27 40–41 33–34 42 
 Borderline 26 36 — — 
 Deficient — — — — 
Memory 
 Superior — — — — 
 Above Average 24* 58–63 24 60 
 Average 20–23 47–53 23* 44–56 
 Below Average 18 42–43 21–22* 37–43 
 Borderline 16 33 20 35 
 Deficient — — — — 
Total 
 Superior 135–136 64–67 — — 
 Above Average 126 58 — — 
 Average 119–125* 45–56 133–139* 44–55 
 Below Average — — 130–132 40–43 
 Borderline — — — — 
 Deficient 98 20 — — 

Notes: Clinical classification t-score ranges are as follows: Superior > 63; Above Average = 57–63; Average = 44–56; Below Average = 37–43; Borderline = 30–36; Deficient ≤ 29.

*As the actual range of raw scores fell across two adjacent T-score ranges and given that the DRS-2 is a screening measure, the decision was made to error on the side of false positives, so the raw score was included in the lower T-score classification category.

Comparisons with original DRS normative data

It can be common practice for neuropsychologists who service Spanish-speaking individuals to use translated and culturally modified measures with normative data for English speakers due to the limited normative data sets available for Spanish speakers on adapted tools. In light of this practice, the following analyses were conducted to investigate the possible clinical misclassification of impairment when utilizing a translated measure with normative data for English speakers.

Utilizing the original English normative data (Jurica et al., 2001) to adjust for age on ST-DRS-2 Total scores, the following Spanish-speaking HCs were misclassified as impaired: four (13.3%) participants with 6 years of education, one (3.33%) with 7–12 years, two (6.67%) with 13–15 years, and no participants with 16–19 years of formal schooling. However, when these age-adjusted scale scores were also corrected for the level of education, the following frequencies of impairment were documented in each group: three (10.0%) participants with 6 years of education, one (3.33%) with 7–12 years, four (13.3%) with 13–15 years, and one (3.33%) with 16–19 years. These rates of misclassification are depicted in Fig. 1.

Fig. 1.

Frequencies of misclassification by education group for ST-DRS-2 Total scores utilizing a cutoff of 1.5SD below the mean of the English normative data.

Fig. 1.

Frequencies of misclassification by education group for ST-DRS-2 Total scores utilizing a cutoff of 1.5SD below the mean of the English normative data.

Sensitivity and specificity of the MMSE, DRS Total, and DRS Memory subscale scores with Spanish speakers

No significant demographic differences were found between Spanish-speaking clinical patients and an age- and education-matched subsample of Spanish-speaking HCs. However, significant differences were observed between these groups on the ST-DRS-2 Total—t(133) = −6.17, p < .001—and subscale scores—Attention: t(133) = −3.31, p < .001; Initiation/Perseveration: t(133) = −6.55, p < .001; Construction: t(133) = −4.05, p < .001; Conceptualization: t(133) = −4.97, p < .001; Memory: t(133) = −4.59, p < .001. Figure 2 presents the receiver operating characteristic (ROC) curves of the MMSE, ST-DRS-2 Memory, and ST-DRS-2 Total. The area under the ROC curve (ROC-A), indicating the overall effectiveness of a screening test (1.00 perfect classification between groups, 0.5 ineffective), was 0.814 for ST-DRS-2 Total, 0.631 for ST-DRS-Memory, and 0.275 for the MMSE. For comparison, we used cutpoints determined by Lyness and colleagues (2006), one to maximize both sensitivity and specificity for each of the screening measures. Results for ST-DRS-2 non-corrected Total score using Lyness and colleagues' cutpoints were: 125 (96% sensitivity and 50% specificity) and 120 (119.5 in our data; 97% sensitivity and 68% specificity). For the ST-DRS-2 non-corrected Memory score, results with Lyness and colleagues' cutpoints were: 19 (18.5 in our data, 96% sensitivity and 62% specificity) and 17 (16.5 in our data, 99% sensitivity and 72% specificity). Maintaining a conservative approach, recommended cutpoints in determining a compromised neurocognitive profile are ≤125 and <17 on the non-corrected Total and Memory scores of the ST-DRS-2, respectively. The MMSE ROC-A results indicated that this measure was not better than chance in successfully classifying the diagnostic groups. In light of the small sample sizes stratified by age and education and the low level of acculturation reported by the Spanish-speaking HC group, the normative data presented reveal great sensitivity in that individuals being screened for a neurodegenerative condition will score below the suggested values. While these values will also result in poor specificity, the later is preferred as findings from the ST-DRS-2 will warrant further neuropsychological assessment that may reveal subtle areas of cognitive compromise and provide patients with early and accurate identification of neurocognitive changes.

Fig. 2.

ROC curves of the MMSE, ST-DRS Memory, and ST-DRS Total.

Fig. 2.

ROC curves of the MMSE, ST-DRS Memory, and ST-DRS Total.

Discussion

The present study sought to establish a valid means of assessing the general cognitive status of Spanish-speaking older adults in the USA by investigating HCs and individuals diagnosed with dementia on a literal ST-DRS-2 (Strutt, 2011). For the current sample, Spanish-speaking HCs ranged in age from 50 to 80, with 6–19 years of education, and originated from 15 countries of Central and South America—commensurate with the reports provided by the U.S. Census Bureau (U.S. Census Bureau, 2012). Such data, in conjunction with the considerable variability in years of U.S. residency and self-reported symptoms of anxiety and depression, suggest that the current sample reflects the immense heterogeneity of community-dwelling Spanish-speaking older adults residing in the USA. While both age and education were identified as significant predictors of ST-DRS-2 Total scores for the total sample of Spanish-speaking HCs, a stronger relationship was observed between ST-DRS-2 Total scores and education than with age. These results are inconsistent with those of the original English normative data (Jurica et al., 2001), which primarily correct for age, and secondarily for the level of education. Acculturation also appears to be an important factor for clinicians to consider when interpreting ST-DRS-2 performance in primarily Spanish-speaking older adults, given the significant relationship found between self-reported levels of acculturation and total scores on this measure.

Consistent with the U.S. Census reports on educational attainment by ethnic background (U.S. Census Bureau, 2012), the current sample of English-speaking HCs reported an average education level of nearly 4 years greater than that of the entire sample of Spanish-speaking HCs. Thus, while comparable rates of misclassification were observed between English- and Spanish-speaking HCs with the original normative data, differences in the rates of misclassification between these two groups may have been obscured by the fact that the subsample of Spanish-speaking HCs used for comparison was among the most highly educated of our entire sample. Nevertheless, English-speaking HCs significantly out-performed their age- and education-matched Spanish-speaking counterparts on ST-DRS-2 Total and subscale scores, and the inter-correlations among the demographic variables and the Total and subscale scores of the outcome measure varied between the two language groups.

Of the DRS-2 subscales, the greatest difference between English- and Spanish-speaking HCs was found on the Memory subscale. However, it is important to note that the majority of errors committed by Spanish-speaking HCs were on three specific items included in the orientation subtotal of the ST-DRS-2 Memory subscale, which require examinees to provide the full name of U.S. government officials, including the current president (25.2%), governor (81.1%), and mayor (77.6%). The removal of these items produced comparable scores between English- and Spanish-speaking HCs on this subscale, and level of acculturation emerged as the only significant predictor of orientation subtotals. Such results may be attributable to the linguistic status of primarily Spanish-speaking older adults, whose limited level of acculturation may subsequently limit their involvement in U.S. politics and media. Another possible explanation could be that due to their particular level of acculturation, the culture-specific names of such public figures are not salient to those Spanish-speaking HCs, which make them more difficult to encode and recall. Nevertheless, these findings suggest that performance on several orientation items of the ST-DRS-2 Memory subscale may be contingent upon acculturation level rather than cognitive ability (i.e., memory) and may thus compromise the construct validity of this subscale.

Although Spanish-speaking HCs obtained significantly lower scores than their English-speaking counterparts, significant differences in performance were still observed between Spanish-speaking dementia patients and a subsample of age- and education-matched Spanish-speaking HCs on ST-DRS-2 Total and subscale scores. Both ST-DRS-2 Total and Memory subscale scores produced greater classification accuracy than the MMSE; however, while Total and Memory subscale scores produced similar sensitivity, ST-DRS-2 Total scores yielded the greatest corresponding rates of sensitivity and specificity. These results differ from those reported by Lyness and colleagues (2006) who found no significant differences between the classification accuracy of these three measures. The Lyness sample included 41 bilingual individuals and a measure of acculturation was not used, thus these differences in methodology appear to have influenced their results. Given that the MMSE consists of the same items included in the orientation subtotal of the ST-DRS-2 Memory subscale (discussed above), the lower classification accuracies yielded by these measures may be attributable to the inclusion of a greater proportion of scale items that are significantly influenced by level of acculturation (i.e., knowledge of U.S. politics). Alternatively, while ST-DRS-2 Total scores include the Memory subscale, the psychometric properties of the entire instrument appear to be augmented by the incorporation of several subscales tapping a variety of cognitive domains.

Limitations of the present study include the modest sample size and the large number of statistical analyses, as well as the exclusion of individuals with significantly low levels of education (i.e., <6 years). An additional limitation is the inclusion of only monolingual Spanish-speakers as opposed to bilinguals. Future research with Spanish-speakers should employ a larger sample size and include individuals with fewer than 6 years of education. Other recommendations for future research are to examine the validity and reliability of this translated measure in comparison to the English DRS-2. It would also be interesting to compare the performance of monolingual and bilingual Spanish-speakers and explore the relationship between language preference, overall level of acculturation, and ST-DRS-2 performance.

In conclusion, the findings of the current study suggest that education plays a key role in performance and should be considered in the assessment of primarily Spanish-speaking older adults residing in the USA. However, level of acculturation also appears to be a leading factor that can influence the performance of primarily Spanish speakers as opposed to English speakers on this dementia screening measure. Our results highlight the need to provide rigorously translated measures and to consider how language and culture influence the neuropsychological stimuli used in an attempt to avoid underperformance as a result of unfamiliarity with names and words that are not common in U.S. subcultures. If acculturation is not accounted for and Spanish-speaking older adults are expected to know names of people whom they do not identify with, that are difficult to pronounce, and whom they have no perceived relation to, it is evident that they may not perform as well as their English-speaking counterparts. Thus, it is essential that clinicians consider an individual's level of acculturation when assessing primarily Spanish-speaking older adults in the USA. The normative data provided in the current study should not only improve the classification accuracy of U.S. primarily Spanish speakers on the ST-DRS-2, but should also broaden the population for which this measure may be employed, given the inclusion of individuals as young as 50 years and those with minimal levels of education.

Supplementary material

Supplementary material is available at Archives of Clinical Neuropsychology online.

Funding

This work was funded by the Alzheimer's Association–New Investigator Research Grant (08-90765) to A.M.S.

Conflict of Interest

None declared.

Acknowledgements

We would like to thank the community volunteers who participated in this research.

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