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Biomedical subjects

R Yemm

Publications and source records attributed to R Yemm.

At least 37 records · Page 2Linked to original sources
PubMed1983

The use of biofeedback to obtain jaw-muscle relaxation in denture-wearing subjects.

A group of ten edentulous patients, who had experienced persistent soreness of the mucous membrane underlying their lower dentures, have been shown to exhibit a tendency towards greater activity of the temporal muscle while ostensibly at rest, compared with a number of normal subjects. A biofeedback technique, based on electromyography, proved effective in teaching the patients to relax during an experiment of approximately 20 min duration. In contrast relatively little change could be achieved by the normal subjects. It is concluded that the results support the hypothesis that muscle tension may contribute to lower denture discomfort, and suggest that biofeedback muscle relaxation training may be a useful method of treatment in such cases.

Biofeedback, Psychology↗
PubMed1983

Measurement of the ability to control jaw muscle forces in man.

Subjects were asked to track a moving waveform on an oscilloscope screen, with the output of a force transducer placed between the teeth. It was found that, after a learning period, the error depended upon the clenching force, and that, over the force range studied, the greater the effort demanded, the greater the error.

Adult↗
PubMed1980

The effect of stimulus strength on the jaw-jerk response in man.

The jaw-jerk response was elicited in seven adult male subjects by tapping on the chin in a downward direction. The magnitude of the applied taps was varied subjectively by the operator, and the downward acceleration of the mandible measured by means of a calibrated piezo-electric accelerometer fixed to the lower anterior teeth. The taps were applied during voluntary clenching by the subject, controlled by means of a force transducer placed between upper and lower teeth. The electrical response of masseter and temporal muscles was found to increase both with increasing stimulus strength and with voluntary clenching force. However, only by averaging a number of responses were clear relationships demonstrated, there being other variables, affecting the muscles independently, which it has not been possible to identify and control. It is concluded therefore, that quantitative analysis of the electromyograms of the jaw closing muscles following chin-tap stimuli is not a satisfactory method for testing for abnormality in excitability of the neuromuscular system involved in the jaw-jerk response.

Adolescent↗
PubMed1978

Measurement of lip posture and interaction between lip posture and resting face height.

A method for measurement of lip incompetence is described. Electromyographic techniques were used to obtain relaxation of the muscles of the lip and of a jaw elevator muscle. Standardized photographs were taken of the subject's profile, from which lip separation and face height were measured. Variation was found in successive measurements of lip posture, some of which appeared to depend upon mandibular posture. With the teeth in occlusion, lip separation was reduced. Active maintenance of lip contact by the subject was often associated with a reduction in lower face height, which may have been a direct consequence of the lip muscle activity, or of jaw elevator activity facilitating the lip closure.

Adolescent↗
PubMed1977

The orderly recruitment of motor units of the masseter and temporal muscles during voluntary isometric contraction in man.

1. The contractile properties of the motor units of the masseter and temporal muscles of human subjects were studied during voluntary isometric contractions, using a method previously employed to examine units of a small hand muscle. 2. Over the range of forces studied (0-6 kg), the units of both muscles were recruited in an orderly fashion, with a nearly linear relationship between the voluntary force at which units were recruited and their measured twitch tensions. 3. The range of contraction times (25-90 msec) was similar to that observed for the hand muscle. In some subjects it seemed that small units, recruited at low forces, exhibited shorter contraction times.

Action Potentials↗
PubMed1976

Neurophysiologic studies of temporomandibular joint dysfunction.

An attempt has been made to relate clinical thinking to available experimental evidence of the physiological background to temporomandibular joint dysfunction. There is little or no evidence that the condition results from displacement of the mandibular condyles. The contention that muscle hyperactivity is a primary cause receives some experimental support, but there is no clear evidence that malocclusion of the teeth leads, through reflex mechanisms, to maintained hyperactivity. Instead there is an increasing weight of evidence that hyperactivity of jaw closing muscles may originate in the central nervous system. It is concluded that such centrally induced activity may be sufficient to cause muscle damage, which leads to disturbed function, local pain and tenderness and to pain referred to adjacent structures.

Animals↗