Brain : a journal of neurology
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Cognitive abnormalities are common in Parkinson's disease, with important social and economic implications. Factors influencing their evolution remain unclear but are crucial to the development of targeted therapeutic strategies. We have investigated the development of cognitive impairment and dementia in Parkinson's disease using a longitudinal approach in a population-representative incident cohort (CamPaIGN study, n = 126) and here present the 5-year follow-up data from this study. ⋯ In contrast, COMT genotype had no effect on dementia, but a significant impact on Tower of London performance, a frontostriatally based executive task, which was dynamic, such that the ability to solve this task changed with disease progression. Hence, we have identified three highly informative predictors of dementia in Parkinson's disease, which can be easily translated into the clinic, and established that MAPT H1/H1 genotype is an important risk factor with functional effects on tau transcription. Our work suggests that the dementing process in Parkinson's disease is predictable and related to tau while frontal-executive dysfunction evolves independently with a more dopaminergic basis and better prognosis.
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Complex regional pain syndrome (CRPS) occurs after stroke, but most cases develop after peripheral trauma and without evidence of brain trauma. However, CRPS is associated with symptoms that appear similar to those observed in patients suffering from hemispatial neglect. Ten participants (four males) with CRPS of one arm performed temporal order judgements of pairs of vibrotactile stimuli, one delivered to each hand, at one of 10 possible stimulus onset asynchronies, under two conditions: arms held each side of the midline and arms crossed over the midline. ⋯ There was no effect of the side of symptoms. These results show that CRPS is associated with a deficit in tactile processing that is defined by the space in which the affected limb normally resides, not by the affected limb itself, and which relates to the relative cooling of the affected limb. This pattern is consistent with data from those with hemispatial neglect after stroke and raises the possibility that chronic CRPS involves a type of spatial neglect.