Deep brain stimulation for Huntington's disease: long-term results of a prospective open-label study.

UNLABELLED: OBJECT.: To date, experience of globus pallidus internus (GPi) deep brain stimulation (DBS) in the treatment of Huntington's disease (HD) has been limited to a small number of case reports. The aim of this study was to analyze long-term motor outcome of a cohort of HD patients treated with GPi DBS. METHODS: Seven patients with pharmacologically resistant chorea and functional impairment were included in a prospective open-label study from 2008 to 2011. The main outcome measure was the motor section of the Unified Huntington's Disease Rating Scale. The primary end point was reduction of chorea. RESULTS: Patients underwent MRI-guided bilateral GPi implantation. The median duration of follow-up was 3 years. A significant reduction of chorea was observed in all patients, with sustained therapeutic effect; the mean improvement on the chorea subscore was 58.34% at the 12-month follow-up visit (p = 0.018) and 59.8% at the 3-year visit (p = 0.040). Bradykinesia and dystonia showed a nonsignificant trend toward progressive worsening related to disease evolution and partly to DBS. The frequency of stimulation was 130 Hz for all patients. DBS-induced bradykinesia was managed by pulse-width reduction or bipolar settings. Levodopa mildly improved bradykinesia in 4 patients. Regular off-stimulation tests confirmed a persistent therapeutic effect of DBS on chorea. CONCLUSIONS: GPi DBS may provide sustained chorea improvement in selected HD patients with pharmacologically resistant chorea, with transient benefit in physical aspects of quality of life before progression of behavioral and cognitive disorders. DBS therapy did not improve dystonia or bradykinesia. Further studies including quality of life measures are needed to evaluate the impact of DBS in the long-term outcome of HD.

[Prototypic value of semantic intrusion errors in Alzheimer's disease]. / Valeur prototypique des intrusions sémantiques dans la maladie d'Alzheimer.

Semantic intrusions are inappropriate responses frequently observed in patients with Alzheimer's disease. They belong to the same category as the words to be remembered, but their prototypic value remains largely unexplored. The prototype is the most representative word in a particular lexical category. The prototypic value is measured according to different criteria: written and oral lexical frequency, frequency of use, degree of typicality, degree of familiarity and rank of quotation. The objective of the study was to evaluate the prototypic value of intrusions produced by 17 Alzheimer's patients with mild to severe dementia, during the cued recall of the Grober & Buschke procedure (RL/RI 16 items). The prototypic value was compared to the categorial norms provided by 1) 17 control subjects and 2) the lexical database "Lexique 3". The results show that intrusions had a significantly higher prototypic value than targeted items. The prototypic value increased with the progression of the disease, and according to the evaluation criteria used. Thus with the criteria "frequency of use", "degree of typicality" and "degree of familiarity," the prototypic value increased exponentially with the severity of dementia. In contrast, in spite of the development of the pathology, the prototypic value decreased when assessed by the criteria of "rank of quotation", and "lexical frequency" (oral and written). In conclusion, the qualitative analysis of the prototypic value of intrusion errors in Alzheimers opens up new clinical and methodological considerations.