Clinical application of the frequency spectra obtained from the movement of the body's center of gravity during standing

Abstract

The present study deals with the pathognomonic signs found in the spectral patterns of the body's center of gravity during standing.
The static sensonograph using the strain gauge technique, was used to obtain, from a subject standing normally on the platform, a continuous record of the movement in the horizontal plane. The data was at the same time supplied to a data recorder, which separately stored this data of lateral and antero-posterior movement on the tape. The recorded data on the tape was fed into a digital computer for the spectral analysis, by means of the Fourier technique.
The experiments were conducted on 102 vertiginous or ataxic patients. Each subject was placed on the platform of the sensonograph with feet together and asked to face straight ahead. Recordings were made with the eyes both open and closed. Each set of recordings was repeated three times in order to verify the reliability of the examination.
Six basic pat erns of the frequency spectra were obtained.
1) Peripheral vestibular lesion
The frequency spectrum in the closed eye trial showed a peak or amplitude augmentation at 0.2 to 0.3Hz.
2) Spinal lesion
The frequency pattern with eyes closed closely resembled that with the eyes open except for the higher peaks in the closed eye test.
3) Cerebellar lesion
The frequency spectra were of wide range extending to above 2Hz with several high peaks in the antero-posterior component and one in the lateral component.
4) Cerebral lesion
The basic potential in the movement of the center of gravity was relatively high throughout the spectra (below 3Hz).
5) Parkinsonism
Very low frequency spectra were recorded.
6) Proprioceptive hyperactivity
There was a characteristic pattern of frequency spectra showing 2.0 to 2.5Hz peak in the lateral and/or antero-posterior component.