BackgroundHuntington's disease (HD) is a fatal inherited neurodegenerative disease, caused by a

MRI findings of asymmetric frontoparietal atrophy in CBD and midbrain atrophy in PSP are the most consistent and useful aids to careful clinical evaluation for differentiating between the two diseases.

The role of the cerebellum in cognition, both in healthy subjects and in patients with cerebellar diseases, is debated. Neuropsychological studies in spinocerebellar ataxia type 1 (SCA1) and type 2 (SCA2) demonstrated impairments in executive functions, verbal memory, and visuospatial performances, but prospective evaluations are not available. Our aims were to assess progression of cognitive and psychiatric functions in patients with SCA1 and SCA2 in a longitudinal study. We evaluated at baseline 20 patients with SCA1, 22 patients with SCA2 and 17 matched controls. Two subgroups of patients (9 SCA1, 11 SCA2) were re-evaluated after 2 years. We tested cognitive functions (Mini Mental State Examination, digit span, Corsi span, verbal memory, attentional matrices, modified Wisconsin Card Sorting Test, Raven Progressive Matrices, Benton test, phonemic and semantic fluency), psychiatric status (Scales for Assessment of Negative and Positive Symptoms, Hamilton Depression and Anxiety Scales), neurological conditions (Scale for Assessment and Rating of Ataxia), and functional abilities (Unified Huntington Disease Rating Scale–part IV). At baseline, SCA1 and SCA2 patients had significant deficits compared to controls, mainly in executive functions (phonemic and semantic fluencies, attentional matrices); SCA2 showed further impairment in visuospatial and visuoperceptive tests (Raven matrices, Benton test, Corsi span). Both SCA groups had higher depression and negative symptoms, particularly apathy, compared to controls. After 2 years, motor and functional disability worsened, while only attentive performances deteriorated in SCA2. This longitudinal study showed dissociation in progression of motor disability and cognitive impairment, suggesting that in SCA1 and SCA2 motor and cognitive functions might be involved with different progression rates.

We examined cognitive and psychiatric disturbances in patients with Huntington's disease (HD) in comparison to at-risk asymptomatic subjects. Cognitive and psychiatric scales and an HD motor scale were administered to 40 HD patients, 17 pre-symptomatic HD gene carriers (AR+) and 28 non gene carriers (AR-). HD patients did worse than AR+ and AR- in all motor, cognitive and psychiatric measures, while AR+ and AR-subjects did not differ between each other. HD patients had high scores for negative psychiatric symptoms, but there was no correlation between illness duration and psychiatric or cognitive performance. In HD, disease course and symptomatology are heterogeneous and negative psychiatric symptoms are common.

Limb apraxia is an important diagnostic sign of cortico-basal degeneration (CBD), although it is also found in progressive supranuclear palsy (PSP). We investigated whether the severity of apraxia differed between proximal and distal arm movements in the two diseases, as suggested by their differing patterns of motor impairment. We studied 24 CBD patients, 25 PSP patients, and 19 healthy controls using a battery of cognitive tests and an ideomotor apraxia test that examined imitation of hand and of whole arm gestures separately. CBD and PSP patients did not differ in general characteristics or disability and were similarly impaired in cognitive performance. Within-group differences between distal and proximal gesture scores were significant only for CBD patients ( p=0.007), in whom distal movements were more compromised. This finding suggests the presence of limb kinetic apraxia in CBD, perhaps in association with ideomotor apraxia.