Premium
The resonant component of human physiological hand tremor is altered by slow voluntary movements
Author(s) -
Lakie Martin,
Vernooij Carlijn A.,
Osborne Timothy M.,
Reynolds Raymond F.
Publication year - 2012
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2011.226449
Subject(s) - rhythm , physical medicine and rehabilitation , electromyography , movement (music) , noise (video) , neuroscience , psychology , physics , medicine , computer science , acoustics , artificial intelligence , image (mathematics)
Key points • Postural physiological hand tremor has a prominent component at ∼8 Hz unlike the associated EMG. Consequently, the gain between EMG and tremor is sharply peaked at ∼8 Hz. • Deduction and a simple model using pre‐recorded EMG or random noise as an input show that the ∼8 Hz peak is a consequence of resonance. • During voluntary movement the gain peak enlarges and shifts to a lower frequency but the EMG spectrum shows no corresponding changes. This reflects muscle thixotropy. Adjustment of the muscle properties of the model reproduces the effect. • These findings suggest that the rhythm of hand tremor in posture and movement is related to muscle and limb mechanics rather than a neural oscillator. • The discovery that the gain relating EMG to acceleration is very different when static and moving has implications for the control of movement in health and disease.