Characteristics of accelerometric activity of the head in healthy subjects at rest and in postures.

OBJECTIVE

Head tremor occurs in various neurological disorders, yet quantitative data on head movements in healthy individuals are lacking. We aimed to provide the first accelerometric database of physiological head movements.

METHODS

Accelerometric activity of the head and EMG of neck muscles of healthy volunteers was recorded. Quantitative characteristics (intensity, peak frequency, center frequency, frequency dispersion) were determined at rest and in various postural positions. Data were statistically analysed.

RESULTS

Power spectra of the accelerometric and EMG activity did not show any spectral peak in any position of the head. The center frequency of the accelerometric activity was 11.19 ± 1.25 Hz in all head positions. The frequency dispersion around center frequency was 7.23 ± 0.58 Hz. Weight loading during posture increased the intensity of the accelerometric signal compared to postural position without weight loading.

CONCLUSIONS

We created the first database of accelerometric activity of head movements in healthy subjects. Using accelerometry, no rhythmic movement of the head could be detected in any position.

SIGNIFICANCE: Our finding suggests that tremor with characteristics similar to physiological limb tremor is absent in the head. Although these results may have implications for the current concept of physiological head tremor they should be verified by further studies using different methodologies.