Objective: To examine differences between United States (US) and Latin American (LA) norms classifying cognitive impairment using standardized neuropsychological measures to assess cognition in Parkinson’s disease (PD).

Background: Neuropsychological evaluation of LA Spanish speakers has been limited to classification of impairment according to US population based norms. Recently published norms based on LA Spanish speakers allow for comparisons in classification of impairment.

Methods: A medical record review of neuropsychological evaluations conducted in Spanish in 105 PD patients seeking deep brain stimulation (DBS) surgical treatment was conducted. Raw scores were obtained for two language measures used to assess cognition in PD, the Boston Naming Test (BNT, N=87) and Category Fluency (CF, N=105).  Standard scores and percentiles were calculated based on norms from the US and 4 LA countries. Scores were classified as impaired if they were at or below the 5^th percentile. Proportion of scores classified as impaired vs. normal were compared.

Results: When using US-based norms, stratified by age and education, 42.5% of BNT scores were classified as impaired and 20% were impaired for CF. Chi-square analyses reveal significantly different proportions of impairment for these same individuals when using LA norms. Proportions of scores classified as Borderline to Superior for both tests also changed significantly, according to the whether US or LA norms were used.

Conclusions: Diagnostic impressions and medical decisions, including whether or not to pursue DBS, often rely on neuropsychological evaluation  results. The growing demographic of LA Spanish speaking PD patients in the US and the lack of appropriate norms to assess performance is becoming increasingly problematic. The current data highlight significant differences between US and LA norms as well as considerable variability among different LA countries. Our findings underscore the need to reconsider how patients are classified as normal vs. impaired and to proceed with caution when making diagnostic decisions based on cut scores.  Future directions include examining the effect of acculturation on test performance in LA Spanish speakers living in the US.

This abstract will be presented at the Pan American Parkinson’s Disease and Movement Disorders Congress in February 2017.

References: Olabarrieta-Landa, L., Rivera, D., Galarza-del-Angel, J., Garza, M. T., Saracho, C. P., Rodríguez, W., . . . Arango-Lasprilla, J. C. (2015). Verbal Fluency Tests: Normative data for the Latin American Spanish speaking adult population. NeuroRehabilitation, 37(4), 515-561. doi: 10.3233/NRE-151279

Olabarrieta-Landa, L., Rivera, D., Morlett-Paredes, A., Jaimes-Bautista, A., Garza, M. T., Galarza-del-Angel, J., . . . Arango-Lasprilla, J. C. (2015). Standard form of the Boston Naming Test: Normative data for the Latin American Spanish speaking adult population. NeuroRehabilitation, 37(4), 501-513. doi: 10.3233/NRE-151278

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MDS Abstracts - https://www.mdsabstracts.org/abstract/classification-of-neurocognitive-impairment-in-spanish-speaking-parkinsons-disease-patients/