Side of symptom onset affects motor dysfunction in Parkinson's disease.

The healthy brain appears to have an asymmetric dopamine distribution, with higher levels of dopamine in the left than in the right striatum. Here, we test the hypothesis that this neurochemical asymmetry renders the right striatum relatively more vulnerable to the effects of dopaminergic denervation in Parkinson's disease (PD). Using the pegboard dexterity test, we compared motor performance of both hands between healthy subjects (n=48), PD patients with predominantly right-hemispheric dopamine depletion (PD-RIGHT; n=83) and PD patients with more severe left-hemispheric dopamine depletion (PD-LEFT; n=103). All subjects were right-handed. After adjusting for hand-dominance effects, we found that PD-RIGHT patients exhibited a 55% larger difference between right and left dexterity scores than PD-LEFT patients. This effect could be attributed to greater motor dysfunction of the more-affected hand in PD-RIGHT patients, while the less-affected hand performed similarly in both groups. We conclude that the side of symptom onset affects motor dysfunction in PD, and suggest that the non-dominant right hemisphere may be more susceptible to dopaminergic denervation than the dominant left hemisphere.

Diagnostic value of asymmetric striatal D2 receptor upregulation in Parkinson's disease: an [123I]IBZM and [123I]FP-CIT SPECT study.

INTRODUCTION: Striatal postsynaptic D2 receptors in Parkinson's disease (PD) are thought to be upregulated in the first years of the disease, especially contralateral to the clinically most affected side. The aim of this study was to evaluate whether the highest striatal D2 binding is found contralateral to the most affected side in PD, and whether this upregulation can be used as a diagnostic tool. METHODS: Cross-sectional survey was undertaken of 81 patients with clinically asymmetric PD, without antiparkinsonian drugs and with a disease duration of < or = 5 years and 26 age-matched controls. Striatal D2 binding was assessed with [123I]IBZM SPECT, and severity of the presynaptic dopaminergic lesion with [123I]FP-CIT SPECT. RESULTS: The mean striato-occipital ratio of [123I]IBZM binding was significantly higher in PD patients (1.56 +/-0.09) than in controls (1.53 +/-0.06). In PD patients, higher values were found contralateral to the clinically most affected side (1.57 +/-0.09 vs 1.55 +/-0.10 ipsilaterally), suggesting D2 receptor upregulation, and the reverse was seen using [123I]FP-CIT SPECT. However, on an individual basis only 56% of PD patients showed this upregulation. CONCLUSION: Our study confirms asymmetric D2 receptor upregulation in PD. However, the sensitivity of contralateral higher striatal [123I]IBZM binding is only 56%. Therefore, the presence of contralateral higher striatal IBZM binding has insufficient diagnostic accuracy for PD, and PD cannot be excluded in patients with parkinsonism and no contralateral upregulation of D2 receptors, assessed with [123I]IBZM SPECT.

New parkin mutations and atypical phenotypes in families with autosomal recessive parkinsonism.

The frequency of parkin mutations was evaluated in 30 families of highly diverse geographic origin with early-onset autosomal recessive parkinsonism. Twelve different mutations, six of which were new, were found in 10 families from Europe and Brazil. Patients with parkin mutations had significantly longer disease duration than patients without the mutation but with similar severity of disease, suggesting a slower disease course. Two patients with parkin mutations had atypical clinical presentation at onset, with predominant tremor when standing.

Improvement of voicing in patients with Parkinson's disease by speech therapy.

Speech therapy in PD patients, focusing on an increase of phonatory-respiratory effort, has adverse effects because it raises vocal pitch and laryngeal muscle tension. The authors' approach, the Pitch Limiting Voice Treatment (PLVT), increases loudness but at the same time sets vocal pitch at a better level. In this study, the Lee Silverman Voice Treatment ("think loud, think shout") and PLVT ("speak loud and low") are compared. Both treatments produce the same increase in loudness, but PLVT limits an increase in vocal pitch and prevents a strained or pressed voicing.

[Dementia with Lewy bodies; 2 patients with exacerbation due to an atypical antipsychotic, but with a favorable response to the cholinesterase inhibitor rivastigmine]. / Dementie met Lewy-lichaampjes; 2 patiënten met verergering door een atypisch antipsychoticum, maar met een gunstige reactie op de cholinesteraseremmer rivastigmine.

In two patients, men aged 80 and 75 years with cognitive deterioration, hallucinations and parkinsonism, the clinical diagnosis 'dementia with Lewy bodies' was established. Treatment with an atypical antipsychotic, risperidone and olanzapine respectively, resulted in an exacerbation of the parkinsonism. Rivastigmine evidently improved the psychosis, the anxiety and the cognitive, mood and behaviour disorders. Titrated treatment with levodopa improved the mobility without an increase of the psychosis. The treatment of dementia with Lewy bodies is complex. Levodopa can lead to an increase in visual hallucinations. Antipsychotics often cause serious side effects, such as increasing parkinsonism, sedation and cognitive deterioration. Cholinesterase inhibitors such as rivastigmine could possibly provide an alternative treatment for the neuropsychiatric symptoms.

Stimulation of growth-hormone release with clonidine does not distinguish individual cases of idiopathic Parkinson's disease from those with striatonigral degeneration.

Multiple System Atrophy (MSA) and idiopathic Parkinson's disease (PD) can be difficult to distinguish. There is an ongoing debate about the diagnostic value of the growth-hormone response to clonidine (CGH-test) in PD and MSA. We investigated whether the CGH-test can identify individual patients in the early stages of PD (n = 21) and Striatonigral Degeneration (SND, n = 11), a particular variety of MSA. Patients were diagnosed on the basis of clinical criteria and IBZM-SPECT. Clonidine induced a greater total serum growth-hormone production in PD than in SND (p = 0.01). However, taking the difference in prevalence of PD and SND into account, and because of the low likelihood ratios of the test, an increase of GH after clonidine increases the pre-test probability for PD by about only 5 %, while an absent response of GH also increases the pre-test probability for SND by about 5 %. We conclude that the CGH-test discriminates between groups of patients with PD and SND, but has little practical diagnostic value for identifying individual patients.