Vibratory perception thresholds at the clavicle in patients with spinal cord injury.

Vibratory perception thresholds were measured by an electromagnetic device applied over the clavicles of 64 patients with spinal cord injuries. Patients with neurological levels of C5 and below had low threshold values (0.63 +/- 0.23 micron of vibration amplitude; mean +/- SD) which were used as reference values. The patients with a neurological level of C1/2 had very high vibratory thresholds bilaterally (above 11.0 micron). Patients with C2/3-3/4 neurological levels also had significantly elevated thresholds (2.56 +/- 2.01 micron), while those with C4-C4/5 levels did not differ significantly from the reference group. The results agree with earlier observations that the C4 segment innervates the clavicle and imply that patients with a lesion at or above C4 may have elevated clavicular vibratory thresholds. It is concluded that vibrametry, a non-invasive technique, is applicable in patients with spinal cord injury and disease, and can be useful for assessment of sensory level and particularly for follow-up of such patients.