IN THE extensive literature concerning intervertebral-disk derangements there has been little comment on vibratory sensation (pallesthesia). This is understandable, since examination of motor power, reflexes, and the sensory modalities of pain and light touch, together with myelography, may make further neurological testing seem superfluous. However, vibratory perception may be impaired or lost in certain localized areas in patients with these lesions, and this paper is a report of 16 such cases. In 14 cases the location of the lesion was proved by myelography and operation, and in 2 cases, by myelography alone. In two of the cases tests were made with a vibrometer1 in addition to the usual methods, so that quantitative comparisons of vibratory perception were possible. In both instances the findings with the vibrometer were similar to the results with a simple tuning fork (C 128).
Disturbances in pallesthesia were not found in all cases of motor