Movement disorders : official journal of the Movement Disorder Society
-
Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia in older people that has only been recognized in the past decade and that remains widely underdiagnosed. At postmortem examination, affected patients show numerous alpha-synuclein-positive Lewy bodies (LB) in many parts of the cerebral cortex, particularly neocortical and limbic areas in addition to the nigral LB degeneration characteristic of Parkinson's disease (PD). Clinical presentation, unlike PD, is with progressive cognitive decline with particular deficits of visuospatial ability as well as frontal executive function accompanied by usually only mildly to moderately severe parkinsonism, which is often akineto-rigid without the classical parkinsonian rest-tremor. ⋯ Ancillary investigations, particularly neuroimaging, can aid in differential diagnosis. We review the present state of the best practice in the clinical diagnosis of DLB. Future modifications of diagnostic criteria would ideally include the full range of clinical presentations that can be associated with LB disease.
-
Multiple system atrophy (MSA), a sporadic progressive synucleinopathy of advanced age, is separated into two clinic opathological subtypes: MSA-P (striatonigral degeneration [SND]) with predominant parkinsonian features and MSA-C (olivopontocerebellar atrophy [OPCA]) with predominant cerebellar ataxia. We propose a novel morphological grading system for both subtypes to compare lesion intensities and their possible clinical validity. Forty-two autopsy cases of MSA were separated into four grades (SND 0-III and OPCA 0-III) based on semiquantitative assessment of neuronal loss, astrogliosis, and presence of alpha-synuclein-positive glial cytoplasmic inclusions (GCI) in striatum, globus pallidus, substantia nigra, pontine basis, cerebellum, and inferior olives. ⋯ Parkinsonism was infrequent in MSA-C even when OPCA was associated with SND, suggesting a masking effect by cerebellar system involvement. High terminal Hoehn and Yahr stages were more frequent in MSA-P (P < 0.01), some with good-to-moderate initial levodopa (L-dopa) response. Although the proposed morphological grading of both MSA-P and -C correlates well with initial symptoms and clinical key features of both types, further prospective studies are required to validate the clinical utility of the proposed MSA grading scales for future intervention studies.
-
Methods provided by nuclear medicine may be helpful in diagnosis of Parkinson's disease (PD). For that purpose, the sensitivity of iodine-123 metaiodobenzylguanidine ([123I]MIBG) scintigraphy and [123I]FP-CIT single photon emission computed tomography (SPECT) was studied in patients with PD onset (Hoehn and Yahr Stage 1). Cerebral [123I]FP-CIT and cardiac [123I]MIBG scintigraphy were carried out in 18 patients with idiopathic Parkinson's disease, according to Hoehn and Yahr Stage 1. ⋯ There was no significant correlation between the H/M ratio relating to MIBG scintigraphy and the motor part of UPDRS, age, disease duration, or gender; however, binding of striatal FP-CIT correlated significantly with cardiac MIBG accumulation. According to the clinical criteria, it might be difficult to prove the diagnosis of PD in patients with slight symptoms and in these cases, FP-CIT SPECT and MIBG scintigraphy may contribute to the early diagnosis of PD. In addition, the functional loss of nigrostriatal and cardiac sympathetic neurons seems to be coupled closely.
-
Changing the strength of synaptic connections between neurons is widely assumed to be the mechanism by which memory traces are encoded and stored in the central nervous system. Plastic changes appear to follow a regional specialization and underlie the specific type of memory mediated by the brain area in which plasticity occurs. Thus, long-term changes occurring at excitatory corticostriatal synapses should be critically involved in motor learning. ⋯ Strikingly, electrophysiological recordings from the dyskinetic group of rats demonstrated a selective impairment of synaptic depotentiation. This survey will provide an overview of plastic changes occurring at striatal synapses. The potential relevance of these findings in the control of motor function and in the pathogenesis both of PD and L-dopa-induced motor complications will be discussed.
-
We report on 2 adult patients presenting with choreic movements as the main clinical feature of mitochondrial cytopathy. One patient exhibited a sensory neuronopathy and ophthalmoplegia. The other had ptosis, a proximal myopathy, and a sensory neuropathy. ⋯ No mutations in mitochondrial DNA were detected. The choreic movements observed in juvenile forms of mitochondrial cytopathy are rarely observed in adults. Although striatal vulnerability is commonly reported in patients with mitochondrial disorders, the mechanism by which the mitochondrial dysfunction leads to chorea is not known.