Neuropsychological performance and disease burden in individuals at risk of developing Huntington disease.

INTRODUCTION: Huntington disease (HD) is a hereditary neurodegenerative disorder. Thanks to predictive diagnosis, incipient clinical characteristics have been described in the prodromal phase. OBJECTIVE: To compare performance in cognitive tasks of carriers (HDC) and non-carriers (non-HDC) of the huntingtin gene and to analyse the variability in performance as a function of disease burden and proximity to the manifest stage (age of symptom onset). METHOD: A sample of 146 participants in a predictive diagnosis of HD programme were divided into the HDC (41.1%) and non-HDC groups (58.9%). Mathematical formulae were used to calculate disease burden and proximity to the manifest stage in the HDC group; these parameters were correlated with neuropsychological performance. RESULTS: Significant differences were observed between groups in performance on the Mini-Mental State Examination (MMSE), Stroop-B, Symbol-Digit Modalities Test (SDMT), and phonological fluency. In the HDC group, correlations were observed between disease burden and performance on the MMSE, Stroop-B, and SDMT. The group of patients close to the manifest stage scored lowest on the MMSE, Stroop-B, Stroop-C, SDMT, and semantic verbal fluency. According to the multivariate analysis of covariance, the MMSE effect shows statistically significant differences in disease burden and proximity to onset of symptoms. CONCLUSIONS: Members of the HDC group close to the manifest phase performed more poorly on tests assessing information processing speed and attention. Prefrontal cognitive dysfunction appears early, several years before the motor diagnosis of HD.

Stroop Color-Word Interference Test: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Stroop Test across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the Stroop Test, as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained 14-36% of the variance in Stroop Word scores, 12-41% of the variance in the Stoop Color, 14-36% of the variance in the Stroop Word-Color scores, and 4-15% of variance in Stroop Interference scores. Although t-tests showed significant differences between men and women on the Stroop test, none of the countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated. CONCLUSIONS: This is the first normative multicenter study conducted in Latin America to create norms for the Stoop Test in a Spanish-Speaking sample. This study will therefore have important implications for the future of neuropsychology research and practice throughout the region.

Rey-Osterrieth Complex Figure - copy and immediate recall: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Rey-Osterrieth Complex Figure Test (ROCF) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the ROCF as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained 7-34% of the variance in ROCF copy scores and 21-41% of the variance in immediate recall scores. Although t-tests showed significant differences between men and women on ROCF copy and immediate recall scores, none of the countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated. CONCLUSIONS: The present study is the first to create norms for the ROCF in Latin America. As a result, this study will have important implications for the formation and practice of neuropsychology in this region.

Trail Making Test: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Trail Making Test (TMT) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Mexico, Argentina, Peru, Paraguay, Honduras, Chile, Cuba, Puerto Rico, Guatemala, El Salvador, and Bolivia. Each subject was administered the TMT as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models for the TMT-A explained 23- 50% of the variance, and the final multiple linear models for the TMT-B explained 22- 49% of the variance. Although there were gender differences on the TMT in Mexico, Peru, Paraguay, and Honduras, only Honduras had an effect size greater than 0.3. As a result, gender-adjusted norms were generated for the Trail Making Test-A, but not B, in this country. CONCLUSIONS: The present study is the first to create norms for the TMT in Latin America. As a result, this study will have important implications for the practice of neuropsychology in the future.

Modified Wisconsin Card Sorting Test (M-WCST): Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Modified Card Sorting Test (M-WCST) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico. Each subject was administered the M-WCST as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained between 2-33% of the variance in M-WCST scores. Although t-tests showed significant differences between men and women from seven different countries on the M-WCST, the effect sizes were small. As a result, gender-adjusted norms were not generated. CONCLUSIONS: This is the first normative multicenter study conducted in in Latin America aiming to create norms for the M-WCST; this study will have important implications for the future of neuropsychology in the region.

Hopkins Verbal Learning Test- Revised: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Hopkins Verbal Learning Test- Revised (HVLT-R) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the HVLT-R as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained 17- 45% of the variance in HVLT-R scores. Although t-tests showed significant differences between men and women in Guatemala on the HVLT-R, it was a small effect size. As a result, gender-adjusted norms were not generated. CONCLUSIONS: The results from this study will have a substantial impact on the practice of neuropsychology in Latin America, as this is the first normative multicenter study to develop norms for the HVLT-R in this region.