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.

Neurocognitive function in adult residents of a mining district in Mexico after reducing manganese exposure: Follow-up after 11 years.

BACKGROUND: Little is known about the neurotoxic effects of chronic exposure to airborne Mn once exposure has been reduced. The environmentally exposed and the reference adult populations evaluated in 2002 were followed, after an environmental management program (EMP) was implemented to reduce the exposure in a mining district in Mexico. OBJECTIVE: The aim of this study was to compare the association between exposure to Mn and neurocognitive performance in environmentally exposed and reference groups of adults before and after EMP implementation. METHODS: In 2013, the same battery of neurocognitive tests used in the initial study (2002) was applied to 58 adults exposed to airborne Mn and 30 adults from the reference community. A cumulative exposure index (CEI) was estimated for the study population before and after the EMP. Categorical outcomes were analyzed using logistic regression, and the resulting ORs were compared between studies. Continuous outcomes were analyzed using linear regression. All models were adjusted for age, years of education, socioeconomic status and blood lead levels. RESULTS: Exposed adults from the post-EMP study showed an improvement in fine motor and verbal regulation of motor skills (OR < 1) compared to the exposed adults from the pre-EMP study (OR > 1). In both pre- and post-studies, the exposed adults showed a deterioration in their dynamic organization of motor activity compared to the reference group (p < 0.05); however, they showed no significant change in attention and working-memory performance. DISCUSSION: After four years of a significant reduction in airborne Mn levels resulting from EMP implementation, chronically exposed adults showed an improvement in fine motor and verbal regulation of motor skills; however, the remaining areas of their motor and cognitive functions remained impaired.

Quantitative and qualitative analysis of semantic verbal fluency in patients with temporal lobe epilepsy. / Análisis cuantitativo y cualitativo de la fluidez verbal semántica en pacientes con epilepsia del lóbulo temporal.

INTRODUCTION: Patients with temporal lobe epilepsy (TLE) perform poorly on semantic verbal fluency (SVF) tasks. Completing these tasks successfully involves multiple cognitive processes simultaneously. Therefore, quantitative analysis of SVF (number of correct words in one minute), conducted in most studies, has been found to be insufficient to identify cognitive dysfunction underlying SVF difficulties in TLE. OBJECTIVES: To determine whether a sample of patients with TLE had SVF difficulties compared with a control group (CG), and to identify the cognitive components associated with SVF difficulties using quantitative and qualitative analysis. METHODS: SVF was evaluated in 25 patients with TLE and 24 healthy controls; the semantic verbal fluency test included 5 semantic categories: animals, fruits, occupations, countries, and verbs. All 5 categories were analysed quantitatively (number of correct words per minute and interval of execution: 0-15, 16-30, 31-45, and 46-60seconds); the categories animals and fruits were also analysed qualitatively (clusters, cluster size, switches, perseverations, and intrusions). RESULTS: Patients generated fewer words for all categories and intervals and fewer clusters and switches for animals and fruits than the CG (P<.01). Differences between groups were not significant in terms of cluster size and number of intrusions and perseverations (P>.05). CONCLUSIONS: Our results suggest an association between SVF difficulties in TLE and difficulty activating semantic networks, impaired strategic search, and poor cognitive flexibility. Attention, inhibition, and working memory are preserved in these patients.

Semantic verbal fluency in elderly Mexican adults: Reference values.

INTRODUCTION: The semantic verbal fluency test (SVF) is sensitive to detecting cognitive decline. It is fast and easy to use in any cultural context; therefore, it is included in most of the neuropsychological assessment protocols. OBJECTIVE: To estimate normative values for the SVF test (animals), in an elderly population aged 65 years and over. MATERIAL AND METHOD: 1233 subjects who were healthy, cognitively preserved, residents of two areas (rural and urban) of Mexico were assessed. A neurological and neuropsychological exploration battery was applied, including SVF. RESULTS: The age average was 73+6 and schooling was 4.0+3.9 years, with 59% women. The average of the words generated in the SVF test was 14+5, and a correlation of 0.16 of these scores with age, education, and gender was found (p<.001), this allowed the estimation of the percentiles in accordance with these variables. CONCLUSIONS: The most important contribution provided by this study was that the data analysis enabled normative values to be obtained for an elderly Mexican population aged 65 years and over. It was also confirmed, as other neuropsychological assessment studies have done, that the SVF test is influenced by socio-demographic variables, such as age and education, aspects to be considered at the time of obtaining normative values. Finally, it was noted that the average scores obtained were lower than other published reference values, due to the low educational level of our sample.

Effect of environmental manganese exposure on verbal learning and memory in Mexican children.

Manganese (Mn) is an essential metal, but in excess it becomes neurotoxic. Children's developing nervous system may be especially vulnerable to the neurotoxic effects of overexposure to this metal. The aim of this study was to assess the effect of Mn exposure on verbal memory and learning in 7- to 11-year-old children. We tested 79 children living in the Molango Mn-mining district and 95 children from a non-exposed community in the same State of Mexico. The Children's Auditory Verbal Learning Test (CAVLT) was administered. Blood and hair samples were obtained to determine Mn concentrations using atomic absorption spectrophotometry. CAVLT performance was compared between the two groups and multilevel regression models were constructed to estimate the association between biomarkers of Mn exposure and the CAVLT scores. The exposed group presented higher hair and blood Mn (p<0.001) than the non-exposed group (median 12.6 vs. 0.6µg/g, 9.5vs. 8.0µg/L respectively), as well as lower scores (p<0.001) for all the CAVLT subscales. Hair Mn was inversely associated with most CAVLT subscales, mainly those evaluating long-term memory and learning (ß=-0.47, 95% CI -0.84, -0.09). Blood Mn levels showed a negative but non-significant association with the CAVLT scores. These results suggest that Mn exposure has a negative effect on children's memory and learning abilities.

Serum prolactin rises in Mexican school children exposed to airborne manganese.

Early studies on manganese (Mn) exposure have shown that this transition metal affects dopamine neurotransmission. Dopamine serves as a tonic inhibitor of prolactin release in the anterior hypophysis, thus the serum prolactin levels in occupationally Mn exposed workers has been found increased. However, little is known about environmental Mn exposure effect on this hormone. In the present study we assessed serum prolactin in environmentally (mainly through air) exposed children living in the proximity of a rich Mn zone in Mexico and a control group with similar socioeconomic and ethnic characteristics. We also determined Mn levels in blood and hair, hemoglobin and anthropometric variables. Children between 7 and 11 years old were included (77 from Mn exposed and 93 from control communities). Blood Mn was higher in exposed children (median 9.5 µg/L, rank [5.5, 18]) as compared to the control group (median 8 µg/L, rank [5, 14]) (p<0.05, Mann-Whitney). Hair Mn was also increased in the exposed group (median 13.2 µg/g, rank [4.2, 48]) in comparison to the control group (median 0.6 µg/g rank [0.06, 3.6]). Prolactin was found increased in the exposed children (median 12.35 ng/ml, rank [2.90, 33.70]) versus controls (median 7.77 ng/ml, rank [2.7, 23.6]). Positive correlations were found between prolactin and both blood Mn and hair Mn (Rho=0.217 and 0.250, respectively, p<0.05). A linear regression, with prolactin as the dependent variable, showed hair Mn as the determinant variable after adjusting by age, hemoglobin and sex. After a stratification of hair and blood Mn into low, medium and high content, significant associations were also found, confirming the relationship between prolactin and hair Mn. Results suggest that children from these Mn environmentally exposed communities could be at risk of endocrine alterations.

Environmental exposure to manganese and motor function of children in Mexico.

OBJECTIVES: Occupational manganese (Mn) exposure has been associated with motor deficits in adult workers, but data on the potential effects of environmental exposure to Mn on the developing motor function for a children population is scarce. The aim of this study was to evaluate the association between exposure to Mn and motor function of school aged children. METHODS: We conducted a cross-sectional study selecting 195 children (100 exposed and 95 unexposed) between 7 and 11 years old. The following tests were used to evaluate the motor function: Grooved pegboard, finger tapping, and Santa Ana test. Mn exposure was assessed by blood (MnB) and hair concentrations (MnH). We constructed linear regression models to evaluate the association between exposure to Mn and the different test scores adjusting for age, sex, maternal education, hemoglobin and blood lead. RESULTS: The median concentration of MnH and MnB was significantly higher in exposed (12.6 µg/g and 9.5 µg/L) compared to unexposed children (0.6 µg/g and 8.0 µg/L). The exposed children on average performed the grooved pegboard test faster, but made more errors, although these results did not reach statistical significance with neither one of the Mn exposure biomarkers. MnB showed an inverse association on the execution of the finger tapping test (average in 5 trials ß -0.4, p=0.02), but no association was observed with MnH. CONCLUSIONS: A subtle negative association of Mn exposure on motor speed and coordination was shown. In adults, the main effect of environmental Mn exposure has been associated with motor skills, but these results suggest that such alterations are not the main effect on children.

Exposure to manganese: health effects on the general population, a pilot study in central Mexico.

To support a risk assessment of manganese exposure in two communities living within a manganese mining district a cross-sectional study was performed on a sample of the adult population of long-term residents. One community was exposed to a point source from an ore primary refining plant. Manganese is an essential mineral for human life. It is also the fourth in importance for industrial metal making. Data were collected on socioeconomic living conditions, emission sources, environmental media concentrations (air, water, soil, dust, food), respiratory symptomatology, and a neuropsychological examination (Mini-Mental Screening test, the Hooper Visual Organization test, the Ardila-Ostroski, and others). We examined 73 subjects (52 women), most of low socioeconomic status. Environmental air concentrations were 2 to 3 times higher than those in other urban concentrations. Manganese blood concentrations ranged from 7.5 to 88 microg/L, with a median concentration of 15, the upper quartile starting at 20 microg/L; the upper 10% was above 25 microg/L. Lead and manganese were highly correlated; there was an inverse relation to hemoglobin. Reduced levels of plasma lipid peroxidation were associated with blood manganese. Using multivariate logistic regression, we identified B-Mn as increasing the risk of deficient cognitive performance 12 times (Mini-Mental score of less than 17).

[Neuropsychological evaluation in patients with Parkinson's disease]. / Evaluación neuropsicológica de pacientes con enfermedad de Parkinson.

OBJECTIVE: To analyze the neuro-psychological performance of patients with Parkinson's, disease (PD), in comparison with a group of patients with frontal lobe lesions (FLL) and a control group. METHODS: Eighteen patients with PD, 10 patients with FLL and 10 controlls of similar age and scolarity were studied. Neuro-psychological evaluation included tests of the visuospatial, execution, attention and concentration, memory and language areas. The tests were classified in two categories: those requiring motor responses and those that do not. RESULTS: Patients with PD and FLL had lower scores them the controls in the visuospatial, attention and concentration and language areas, with statistical significance in some cases. The differences with the controls persisted in some tests requiring and not requiring motor response. CONCLUSIONS: Frontal lobes have an important role in the neuro-psychological profile of patients with PD. Cognitive deficits in these patients is unrelated to the motor impairment of the disease.

[Significance of support groups in the integrated management of chronically ill patients]. / La trascendencia de los grupos de apoyo en el manejo integral de los enfermos crónicos.

Support groups in terminal and chronic illnesses originated out of the families refusal to accept the pervasive hopelessness associated with these types of diagnosis. The creation of support networks aimed at providing a friendly atmosphere where participants could share their daily burdens. Unlike group therapy or other forms of psychotherapy, support groups do not focus their efforts on carrying out substantial personality changes in its members. Professionally led support groups also differ from lay organizations in that its main thrust lies in health education and management strategies in the home. The primary caretaker is given special priority inasmuch as he she are the ones involved in the daily care of these patients. The present article outlines a revision of the conceptual framework in the field of support groups. Their format, main characteristics and research aims are discussed within the context of a multidimensional approach to patient care.