Journal of neurology, neurosurgery, and psychiatry
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J. Neurol. Neurosurg. Psychiatr. · Apr 2012
ReviewMolecular pathogenesis of Parkinson's disease: update.
Parkinson disease (PD) is a neurodegenerative disease characterised by progressive disturbances in motor, autonomic and psychiatric functions. Much has been learnt since the disease entity was established in 1817. Although there are well established treatments that can alleviate the symptoms of PD, a pressing need exists to improve our understanding of the pathogenesis to enable development of disease modifying treatments. ⋯ Also, genome wide association studies, a powerful approach to identify weak effects of common genetic variants in common diseases, have identified a number of new possible PD associated genes, including PD genes previously detected. However, there is still much to learn about the interactions of the gene products, and important insights may come from chemical and genetic screens. In this review, an overview is provided of the molecular pathogenesis and genetics of PD, focusing particularly on the functions of the PD related gene products with marked research progress.
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J. Neurol. Neurosurg. Psychiatr. · Apr 2012
ReviewThe split hand syndrome in amyotrophic lateral sclerosis.
In amyotrophic lateral sclerosis (ALS), hand muscle wasting preferentially affects the 'thenar (lateral) hand', including the abductor pollicis brevis (APB) and first dorsal interosseous (FDI) muscles, with relative sparing of the hypothenar muscles (the abductor digiti minimi (ADM)). This peculiar pattern of dissociated atrophy of the intrinsic hand muscles is termed the 'split hand' and is rarely seen in diseases other than ALS. The muscles involved in the split hand are innervated through the same spinal segments (C8 and T1), and FDI and ADM, which are differentially affected, are both ulnar nerve innervated. ⋯ But peripheral axonal excitability studies have suggested that APB/FDI motor axons have more prominent persistent sodium currents than ADM axons, leading to higher axonal excitability and thereby more ready degeneration. Pincer or precision grip is vital to human hand function, and frequent use of thenar complex muscles may lead to greater oxidative stress and metabolic demands at both upper and lower motoneurons innervating the APB and FDI. The split hand is a useful diagnostic sign in early ALS, and recent objective studies indicate that the sign has a high degree of specificity.
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J. Neurol. Neurosurg. Psychiatr. · Apr 2012
ReviewVisual hallucinations in the differential diagnosis of parkinsonism.
Visual hallucinations (VH) occur commonly in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) but are reported much less frequently in other neurodegenerative causes of parkinsonism, such as progressive supranuclear palsy, multiple system atrophy and corticobasal degeneration syndrome. This clinical sign may be helpful when considering the differential diagnosis of patients with parkinsonism. ⋯ VH correlate with pathology in the limbic system and more specifically the amygdale that is frequently affected in PD and DLB but relatively preserved in other forms of parkinsonism often misdiagnosed as PD. In this review, the published frequencies of VH in these different conditions are compared to put into context the notion of VH as a clinical clue to underlying Lewy body pathology.