ABSTRACT
The role of sub-cortical structures in language processing, and more specifically of the striatum, remains controversial. In line with psycholinguistic models stating that language processing implies both the recovery of lexical information and the application of combinatorial rules, the striatum has been claimed to be involved either in the former component or in the latter. The present study reconciles these conflicting views by showing the striatum's involvement in both language processes, depending on distinct striatal sub-regions. Using PET scanning in a model of striatal disorders, namely Huntington's disease (HD), we correlated metabolic data of 31 early stage HD patients regarding different striatal sub-regions with behavioural scores on three rule/lexicon tasks drawn from word morphology, syntax and from a non-linguistic domain, namely arithmetic. Behavioural results reflected impairment on both processing aspects, while deficits predominated on rule application. Both correlated with the left striatum but involved distinct striatal sub-regions. We suggest that the left striatum encompasses linguistic and arithmetic circuits, which differ with respect to their anatomical and functional specification, comprising ventrally located regions dedicated to rule computations and more dorsal portions pertaining to lexical devices.
Subject(s)
Corpus Striatum/physiopathology , Huntington Disease/psychology , Language , Adult , Brain Mapping/methods , Comprehension , Corpus Striatum/diagnostic imaging , Female , Humans , Huntington Disease/diagnostic imaging , Huntington Disease/physiopathology , Image Interpretation, Computer-Assisted/methods , Language Tests , Male , Mathematics , Middle Aged , Positron-Emission TomographyABSTRACT
BACKGROUND: Activities of daily living (ADL) and caregiver burden are known to have a major impact on the decision to institutionalize patients with Alzheimer's disease (AD), yet little research has been done on these aspects in patients with frontotemporal dementia (FTD). AIM: To compare ADL and caregiver burden in FTD and in early-onset AD. METHODS: We compared 26 FTD and 28 AD patients with respect to the Neuropsychiatric Inventory (NPI), Mini Mental State Examination, Mattis Dementia Rating Scale (MDRS), Disability Assessment for Dementia (DAD) and Zarit Burden Inventory (ZBI). RESULTS: Demographic variables for FTD and AD were similar. FTD patients obtained a significantly higher NPI behavioral score than AD patients (median, 39.5 vs. 11; p < 0.0001). However, the two groups did not differ in their total DAD score. No correlations were observed between DAD and cognitive status (MDRS) or between DAD and behavioral impairment (NPI). The ZBI was higher in FTD than in AD patients (median, 40 vs. 18.5; p = 0.0004) and was correlated with the NPI in both groups. CONCLUSION: Functional disability was similar in FTD and AD patients. Nevertheless, the caregiver burden was higher in FTD than in AD, a result that has important implications for caregiver help.
