Session Time: 1:45pm-3:15pm
Location: Hall 3FG
Objective: To investigate the pathophysiology of action tremor in motor neuron disease (MND).
Background: MND refers to a spectrum of degenerative diseases affecting motor neurons. Recent clinical and postmortem observations have revealed considerable variability in the phenotype (1). Rhythmic involuntary oscillations of the hands during action, resembling tremor, can occur in MND, but its pathophysiology has not yet been investigated.
Methods: One hundred and twenty consecutive MND patients were screened for tremor. Twelve patients with action tremor and no other movement disorders were found. Ten took part in the study. Tremor was recorded bilaterally using surface electromyography and triaxial accelerometer, with and without a variable weight load. Power spectra of rectified electromyography and accelerometric signal were calculated. To investigate a possible cerebellar involvement, eye blink classic conditioning (EBCC) was performed in five patients.
Results: Action tremor was present in about 10% of our population. All patients showed distal postural tremor of low amplitude and constant frequency, bilateral with a small degree of asymmetry. Two of them showed also simple kinetic tremor. A peak at the electromyography and accelerometric recordings ranging from 4 Hz to 12 Hz was found in all patients. Loading did not change peak frequency in either the electromyographic or accelerometric power spectra. Compared with healthy volunteers, patients had a smaller number of conditioned responses during EBCC.
Conclusions: our data suggest that MND patients can present with action tremor of a central origin, possibly due to a cerebellar dysfunction. This evidence supports the novel idea of MND as a multisystem neurodegenerative disease and that action tremor can be part of this condition.
References: 1. Sabatelli M, Conte A, Zollino M. Clinical and genetic heterogeneity of amyotrophic lateral sclerosis. Clinical genetics. 2013;83(5):408-16.
To cite this abstract in AMA style:A. Latorre, L. Rocchi, M. Stamelou, A. Batla, M. Ciocca, B. Balint, K. Sidle, A. Berardelli, J. Rothwell, K. Bhatia. Tremor in motor neuron disease may be central rather than peripheral in origin [abstract]. Mov Disord. 2018; 33 (suppl 2). https://www.mdsabstracts.org/abstract/tremor-in-motor-neuron-disease-may-be-central-rather-than-peripheral-in-origin/. Accessed December 5, 2023.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/tremor-in-motor-neuron-disease-may-be-central-rather-than-peripheral-in-origin/