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Aims We explored the tendency of patients with HD to attribute mental states to ambiguous stimuli in the form of a series of video-clips involving animated shapes. Some of these animations are considered to involve random movements of two triangles, while others are commonly interpreted as depicting simple or more complex social interactions prompting the inference of mental states to the shapes (e.g. chasing, persuading). Methods Forty patients with genetically determined HD and twenty healthy controls matched for age and gender participated in the study. In addition to the video animations task we administered measures of alexithymia, mood disorder, executive functions and motor symptoms. Results HD gene carriers showed significant evidence of alexithymia in comparison to controls. Moreover, individuals with HD exhibited a deficit in the attribution of intentions on the animations task. In patients with motor onset, aspects of performance on the animations task were correlated with motor symptom severity and alexithymia. However, subgroup analyses revealed a significantly reduced tendency to infer intentions was apparent in patients without motor symptoms and intact executive functions. Conclusions HD is associated with a deficit in the spontaneous attribution of mental states, and therefore a reduced propensity to adopt the intentional stance. Our findings further suggest that subtle changes in ToM can be detected prior to motor onset in HD.Dysexecutive symptoms such as apathy, impulsivity and distractibility have been reported on clinical ground in HD. However previous studies have assessed dysexecutive behavioural disorders using clinical interview or nonspecific questionnaires incorporating other features resulting in highly variable evaluation with poorly defined performance indices. This study aimed to assess dysexecutive behavioural abnormalities in HD, using a validated instrument, the Behavioural Dysexecutive Syndrome Inventory (BDSI).14 patients (mean age: 55.5 years; SD 12.4; range: 34-73; mean duration: 8.7 years; SD=7; range: 2-30; mean MMSE score: 25; SD=3.4) with clinically diagnosed and genetically confirmed HD, were included. The assessment of depressive symptoms (Montgomery Asberg Depression Scale) showed a mild depression in 7 patients.The BDSI is a highly structured caregiver based interview which rates frequency and severity of 12 dysexecutive disturbances (global hypoactivity with apathy, hyperactivity, irritability-impulsivity, euphoria, perseverative behaviour; environmental dependency, social behaviour disorders). The analysis of individual performance was performed using cutoff scores at the 5% level using normative data obtained in 96 controls 1 .The prevalence of behavioural dysexecutive syndrome was high (50%; 95% CI: 24-76). The behavioural profile was characterised by the prominence of irritability (50%), hyperactivity (43%), apathy (29%), disinterest (22%) and difficulties for anticipation (14%).This study based on the BDSI revealed in HD that behavioural dysexecutive disorders a...

BackgroundAlthough age of onset of Huntington’s disease (HD) is mainly determined by the size of the CAG repeat expansion, other factors may play a role. One potential factor is Cognitive Reserve (CR), as it has been shown in other neurodegenerative disorders and ageing. ObjectiveThe objective of this study is to investigate the effect of CR on age of onset in HD and to examine the neural bases underlying the individual differences in executive function that could be due to the effects of CR in HD. MethodsThirty-one HD patients completed a CR questionnaire and were scanned using functional magnetic resonance imaging. We analysed the Resting State Executive Control Network (RS-ECN), a novel approach to study the brain areas underlying executive function. The strength of connectivity with this network was calculated voxel-wise. The difference between the theoeretical and estimated age of onset (26 symptomatic-HD) was calculated for each patient. ResultsOur results revealed that high levels of CR significantly delayed the appearance of clinical symptoms. Functional connectivity and morphometry analysis showed a brain reorganisation modulated by CR, which changed the connectivity strength in the anterior cingulate cortex, in the left superior parietal cortex (SPC) and slowed the volume loss in the bilateral precuneus and the bilateral caudate. Furthermore, higher strength of connectivity in the left SPC was related to better performance in cognitive flexibility (TMT B-A) and working memory (Backward Digits Span) tasks. ConclusionsThese findings provide converging evidence that CR might act as a protective mechanism for the progression of the disease, delaying the onset of symptoms and improving the performance in executive functions by modulating the RS-ECN and slowing brain atrophy.