Patients with rest-tremor and scans with ipsilateral dopaminergic deficit
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Dopamine transporter imaging is typically abnormal in Parkinson’s disease and shows reduced striatal uptake, which is typically greater contralateral to the clinically more affected side. However, tremor-dominant Parkinson’s disease patients may have significantly lower uptake in the striatum ipsilateral to the rest-tremor compared to akinetic-rigid PD patients, implying a possible role of an ipsilateral deficit in the generation of rest-tremor.We report here three patients with rest-tremor and the unexpected finding of an ipsilateral presynaptic dopaminergic deficit with normal uptake contralateral to the rest-tremor in dopamine transporter imaging. We divided them in two groups, with and without a corresponding structural lesion in brain imaging. These data may suggest a role of ipsilateral dopaminergic deficit in the generation of rest-tremor. An explanation of these findings could be damage of crossed dopaminergic fibres from the substantia nigra to thalamus, which can cause motor impairment ipsilateral to dopamine depletion experimentally. This is speculative but there is no doubt that these cases exist and we encourage others to report similar cases, as this may assist in the better understanding of the yet unknown pathophysiology of rest-tremor.
KeywordsIpsilateral DaTSCAN Parkinson’s disease Rest-tremor Asymmetry index
M. Aguirregomozcorta was supported by an EFNS educational fellowship 2009. M.Stamelou was supported by an EFNS scientific fellowship 2010. We thank the patients and their caregivers for their consent to publish the video. This work was undertaken at UCLH/UCL who received a proportion of funding from the Department of Health’s NIHR Biomedical Research Centers funding scheme.
Conflicts of interest
This study has been approved by the appropriate ethics committee and have therefore been performed in accordance with ethical standards laid down in the 1964 Declaration of Helsinki.
Video Segment 1 shows case 1 with rest-tremor of the left hand and a mild intermittent rest-tremor on the right. There is a mild dystonic posturing of her left arm with arms outstretched and some slowness when tapping with the left hand without true bradykinesia. Video Segment 2 shows case 2 with rest- and postural tremor of the left hand (MPG 8022 kb)
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