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Biomedical subjects

M Naeije

Publications and source records attributed to M Naeije.

90 records · Page 5Linked to original sources
PubMed1986

Electromyographic screening of myogenous and arthrogenous TMJ dysfunction patients.

Sixty patients, clinically examined for TMJ dysfunction, were also electromyographically screened. The TMJ dysfunction pain in forty patients was evaluated to be mainly of a myogenous origin and in fourteen patients of a mainly arthrogenous origin. Due to lack of findings in the clinical examination six patients were not to be classified into either of the two groups. They were excluded from the EMG study. For the EMG examination the patients were asked to clench for 30 s in the intercuspal position at 50% of the maximum EMG activity of the masseter muscles. Surface electromyograms of the right and the left masseter and anterior part of the temporalis muscles were monitored. The amplitude of the EMG signal, the duration of the silent period and the changes in the frequency composition of the signal during the 30 s contraction were analysed. Statistically significant differences between the two patient groups were found in EMG amplitude and in silent period duration. However, the difference in silent period duration was due to the dependency of the silent period on the activation level of the muscle. No statistically significant difference in silent period was found when this dependency was corrected for in the data. The EMG parameters related to muscular fatigue phenomena did not show any difference between the two groups. The difference in EMG amplitude and consequently the difference in silent period duration support the clinically made distinction into mainly a myogenous or mainly an arthrogenous origin of TMJ dysfunction pain.

Adult↗
PubMed1984

Correlation between surface electromyograms and the susceptibility to fatigue of the human masseter muscle.

Seventeen healthy male subjects were asked to clench as long as possible in the intercuspal position while keeping the electromyographic activity (EMG) of the masseter muscle at 50 per cent of the maximum activity. The endurance time was used as an indicator for the muscular resistance to fatigue. At the 95 per cent probability level, there was a statistically-significant correlation between the endurance time and the root mean square value (RMS) of the EMG signal, the mean power frequency value (MPF) of the signal and the parameter MPF 100 per cent/MPF10 per cent used as an indicator for the contraction-level dependency of the mean power frequency. There was a strong correlation (p less than 0.001) between the endurance time and the rate of EMG frequency shift to lower frequencies measured during the first 30 s.

Adult↗
PubMed1984

Influence of chin tap force and bite force parameters on the duration of the electromyographic silent period.

Controversy exists as to whether chin tap force and bite force affect the duration of the electromyographic silent period following the jaw jerk reflex during isometric contraction of the elevator muscles of the mandible. This study demonstrates that statistical trends exist showing increased silent period duration for increased tap forces and decreased silent period duration with increased bite forces.

Adult↗
PubMed1984

Relationship of electromyographic parameters in jaw dysfunction patients classified according to Helkimo's index.

Forty-two jaw pain-dysfunction syndrome patients (PDS) were divided into three groups depending on the severity of their condition using the Helkimo clinical dysfunction index. For both the left and right masseter and anterior temporal muscles three parameters of their electromyographic activity were measured, the silent period (SP), the root mean square value (RMS) and the mean power frequency (MPF). During the experiments the patients were instructed to clench as hard as possible in the intercuspal position. No statistically significant differences could be found between the values for any of the muscles measured between the different Helkimo clinical dysfunction groups. However, when the affected side was compared with the unaffected side in this patient material, statistically significant longer silent period durations and greater RMS values were found in the masseter muscles of the affected side group.

Adult↗
PubMed1984

The influence of stimulus type and stimulus strength on the silent period in human masticatory muscles.

The silent period in the jaw-closing muscles of nine healthy subjects was investigated. The stimulus types used were the open-close-clench movement (OCC), the mechanical chin tap and electrical skin stimulation. Irrespective of the jaw-closing speed for the OCC movements only the unmeasurable and single type silent periods were observed. Increasing the chin tap strength resulted in a decreasing percentage of single type silent periods and an increasing number of depressed, double and merged silent periods. The duration of the short and combined silent period was shorter for the OCC movements than for the chin taps. For the chin taps an increasing stimulus strength resulted in longer silent periods. Only the transition from hard to painful chin tap showed a slight, but significant decrease in short silent period duration. The beginning of the late inhibitory period, which could sometimes be evoked by electrical skin stimulation, coincided with the beginning of the second inhibitory phase of the chin-tap evoked double silent period. The long silent period as shown by one of the subjects cast doubt on the validity of the relationship between silent period duration and TMJ dysfunction.

Adult↗
PubMed1982

The effects of beta motor stimulation on the interpretation of signals from muscle spindles.

A previously proposed method for the interpretation of the signals in sensory nerve fibres is extended to incorporate beta activation of muscle spindles. simulations, based on previous experimental observations, of muscles spindles subjected to ramp and hold stretches are used as input to an "interpreter", where the simulated trains of action potentials are reconverted to a length change interpretation. The interpreted signals are compared with the original length change inputs to observe the effects of beta-stimulation and stochastic variability.

Action Potentials↗
PubMed1980

A method for the interpretation of signals in afferent nerves from muscle spindles.

A method is proposed for the interpretation of the signals in sensory nerve fibres. It is applicable to systems in which the transfer function between the input to a sense organ and the action potential firing frequency is known. In the present case, the chelonian muscle spindle is considered since its output to ramp-hold-release and sinusoidal stretches can be rather accurately simulated.

Action Potentials↗
PubMed1980

Phase plane modeling of human jaw movement: reproducibility and rhythm dependency of the RMS error.

The rhythm dependence and reproducibility of the jaw motion error for open-close-clench movements in man have been investigated. The results indicate that the error strongly depends upon the rhythm of movements. Sometimes there is a significant difference (p less than 0.05) between corresponding series of jaw motion errors indicating a lack of reproducibility of the error at a repeat test.

Bruxism↗
PubMed1979

Reproducibility of the normalized electromyographic recordings of the masseter muscle by using the EMG recording during maximal clenching as a standard.

A method of normalizing the integrated EMG recordings from the masseter muscles is introduced. For each subject investigated the maximal clenching force is remarkably constant and reproducible. This makes it possible to normalize the integrated EMG recordings to the EMG activity at the maximal clenching force without having to measure this force at the beginning of every experiment. These normalized integrated EMG activities give a good quantitative impression of the static force exerted by the masseter muscle, and therefore can be compared quantitatively over several experiments. The realtionship between the normalized integrated EMG activities and the clenching force is linear up to approximately 80% of the maximal clenching force.

Bruxism↗
PubMed1979

The reproducibility of movement parameters of the empty open-close-clench cycle in man and their dependency on the frequency of movements.

The reproducibility of the empty open-close-clench cycle has been investigated. Four subjects were asked three times to perform thirty empty open-close-clench movements at each frequency of 1/2, 1 and 2 cycles s-1. To describe such a series of thirty movements a set of nine parameters were selected. By reference to these parameters it was found that the subjects were not always able to exactly reproduce a series of thirty movements at a repeat test. The movement-parameters strongly depended on the frequency of the movements. On increasing the frequency the durations of time in which a movement cycle was divided decreased, while the maximum jaw speeds during opening and closing and the jaw speed just before tooth contact increased. The parameter values chosen to describe the smoothness of the movements performed, indicated that the smoother movements were executed at the higher frequencies.

Adult↗
PubMedDate not supplied

The relationship between posture and curvature of the cervical spine.

OBJECTIVE: To study the relationship between posture and curvature of the cervical spine in healthy subjects. SUBJECTS: The study was composed of 54 healthy students (25 men and 29 women) aged 20-31 yr with a mean age of 24.7 yr. METHODS: Lateral radiographs were taken of the head and cervical spine of the subjects while standing in a neutral position. Cervical spine posture was quantified by the angle of a reference line, composed of reference points of the upper six cervical vertebrae, with the horizontal axis. The curvature of the cervical spine was classified visually as lordotic, straight or reversed. RESULTS: A relationship was found between posture and curvature of the cervical spine (p = .006); a more forward posture of the cervical spine was related to a partly reversed curvature; and a more upright posture was related to a lordotic curvature. Moreover, men more often exhibited a straight curvature, and women more often exhibited a partly reversed curvature. CONCLUSION: The curvature of the cervical spine is related to the subject's posture and gender.

Adult↗