Action‐induced clonus mimicking tremor

Abstract

Action tremor has been described in cerebellar, task-specific, dystonic, or Holmes tremor. We report 2 patients who developed unilateral kinetic or isometric action tremor of the upper extremity, following cervical spondylotic myelopathy and capsular ischemic stroke. Slight motor weakness and spasticity with exaggerated tendon jerks and passive stretch-induced clonus were present on the same limb. The central motor pathways lesions might have been responsible for a hyperexcitability of the stretch-reflex arc and an enhancement of the coactivation of skeletal muscles through a loss of the descending or segmental control of the spinal reflexes. The unusual topography of the symptoms, their occurrence during motion, and the similar frequency of the passive clonus and the action tremor, led us to hypothesize that both patients had prolonged action-induced clonus, mimicking action tremor. Lesions of the central motor pathways lesions might be responsible for action tremor under certain conditions.

Content Validation of the International Classification of Functioning, Disability and Health (ICF) Core Set for Stroke: The Perspective of Occupational Therapists

“…This finding is clearly supported by the literature, which reports a close relationship between stroke and spasticity and the incidence of clonus or tremor (Fraix, Delalande, Parrache, Derambure, & Cassim, 2008;Wu, et al, 2006).…”

“…Furthermore, 93.8% of the participants agreed that b765, Involuntary movement functions, is a problem treated by occupational therapists that is not included in the ICF Core Set for stroke. This finding is clearly supported by the literature, which reports a close relationship between stroke and spasticity and the incidence of clonus or tremor (Fraix, Delalande, Parrache, Derambure, & Cassim, 2008;Wu, et al, 2006).…”

Content Validity of the Extended ICF Core Set for Stroke: An International Delphi Survey of Physical Therapists

“…This finding is clearly supported by literature, which reports a close relationship between stroke and spasticity (hypertonicity) and the incidence of clonus or tremor. 42,43 In addition, validation studies have identified this ICF category as being relevant for occupational therapists 44 and physicians. 45 Regarding the ICF category "b780 Sensations related to muscles and movement functions," which is not represented in the ICF Core Set for stroke, again a high consensus among the participants was found.…”

Bedside clinical assessment of patients with common upper limb tremor and algorithmic approach

“…Clonus is a 5–7 Hz rhythmic involuntary movement that typically occurs in response to a suddenly applied passive stretch on the limb. It might mimic action tremor, but clonus only presents during a passive movement or forceful contraction and is associated with hyperreflexia and spasticity [ 20 , 21 ]. Indeed, the spectrum of hyperkinetic movements are clinically overlapping, starting from the most regular and rhythmic movements in tremor to irregular tremor, high-frequency myoclonus, and irregular jerky movements in typical myoclonus.…”