John McAuley

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 The output from the central nervous system to muscles may be rhythmic in nature. Previous recordings investigating peripheral manifestations of such rhythmic activity are conflicting. This study attempts to resolve these conflicts by employing a novel arrangement to measure and correlate rhythms in tremor, electromyographic (EMG) activity and muscle(More)
In recent years there has been increasing interest in oscillatory neural activity in the CNS and in the role that such activity may have in motor control. It is thought that physiological tremor may be a manifestation in the periphery of such central oscillatory activity and that some pathological tremors are the result of derangement of these oscillators.(More)
Maximum elbow flexor and extensor muscle strength was measured in 9 patients with Parkinson's disease on and off antiparkinsonian medication. In addition, the rate of force generation, the rate of actively returning force to resting levels, and passive release of force "relaxation" were measured in submaximal contractions. The measures of strength and(More)
1. A 10 Hz range centrally originating oscillation has been found to modulate slow finger movements and anticipatory smooth eye movements. To determine if an interaction or linkage occurs between these two central oscillations during combined visuo-manual tracking, frequency and coherence analysis were performed on finger and eye movements while they(More)
The differentiation of psychogenic from organic tremors, particularly those of a dystonic nature, can be difficult on clinical grounds. Entrainment of tremulous movements of different body parts into a single rhythm has been used clinically as a means of distinguishing these tremor forms, based on the inability of a patient with hysterical tremor to(More)
To investigate the possibility that rhythmic activity originating in the central nervous system may modulate human eye movements, anticipatory eye movements were generated by tracking an intermittently obscured sinusoidally moving target. Eight subjects tracked intermittently obscured sinusoids of three different frequencies and of two different amplitudes.(More)
Primary orthostatic tremor is characterized by unsteadiness and shakiness of the legs while standing. It is due to a remarkably strong and regular EMG modulation at approximately 16 Hz that is thought to be of CNS origin. Previous studies have shown that the tremor frequency is the same in all involved muscles and that the time relation between bursts of(More)
OBJECTIVES Although Parkinson's disease is typically characterised by bradykinesia, rigidity, and rest tremor, the possibility that two additional motor deficits are manifest during small hand muscle activity was explored-namely, weakness and abnormal physiological tremor. METHODS A paradigm previously used in normal subjects reliably records the(More)
Despite the fact that Parkinson's disease (PD) is a relatively common neurological condition, the physiological derangements that result in its clinical features remain unclear. On combining findings from psychophysical, clinical and electrophysiological studies, an overriding theme is proposed that PD deficits are essentially quantitative rather than(More)