Lm. Tang et al., A LONGITUDINAL-STUDY OF MULTIMODAL EVOKED-POTENTIALS IN PATIENTS FOLLOWING RADIOTHERAPY FOR NASOPHARYNGEAL CARCINOMA, Neurology, 47(2), 1996, pp. 521-525
Radiation rhombencephalopathy and radiation myelopathy may occur in pa
tients months or years after radiotherapy for malignancy of the head a
nd neck. We obtained multimodal evoked potentials longitudinally in 26
patients with proven nasopharyngeal carcinoma. Recordings were made b
efore radiotherapy and at 1 week, 3 months, 9 months, 15 months, and 2
4 months after radiotherapy. All absolute latencies of evoked response
before and after radiation were within normal limits. However, the I-
III interpeak latencies of brainstem auditory evoked potentials and th
e onset latencies of motor evoked potentials in the whole group of pat
ients at 15 months after radiation were significantly longer than thos
e before radiotherapy, whereas the latencies at 24 months were not sig
nificantly different. The N20 latencies of somatosensory evoked potent
ials after radiotherapy were significantly prolonged at 3 months of fo
llow-up; the prolongation then became normal. They indicate that a sub
clinical reversible radiation-induced dysfunction may occur in the aud
itory, sensory, and motor systems.