Physiological abnormalities in hereditary hyperekplexia

✍ Scribed by Joseph Matsumoto; Peter Fuh; Michael Nigro; Dr. Mark Hallett

• Book ID: 102707343
• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 957 KB
• Volume: 32
• Category: Article
• ISSN: 0364-5134
• DOI: 10.1002/ana.410320108

✦ Synopsis

Five patients from a kindred with hereditary hyperekplexia had physiological testing. The surface-recorded electromyographic pattern of audiogenic muscle jerks was identical to that of the normal acoustic startle reflex. Testing at graded stimulus intensities indicated an increase in the gain of the acoustic startle reflex. Nose-tap stimuli resulted in short-latency generalized electromyographic bursts that were similar to the R1 component of the blink reflex. Electrical stimulation of peripheral nerves elicited a pattern of generalized muscle jerks that was similar to that of the acoustic startie reflex. Somatosensory evoked potentials, brainstem auditory evoked potentials, and cortical auditory evoked potentials were normal. The primary physiological abnormality in hereditary hyperekplexia is widespread elevated gain of vestigial withdrawal reflexes in the brainstem and possibly the spinal cord, most likely resulting from increased excitability of reticular neurons.