Quantitative sensory testing of thermal and vibratory perception in familial dysautonomia

Abstract

Familial dysautonomia (FD) is an inherited disorder that is known to affect both sensory and autonomic functions as a result of incomplete neuronal development and progressive loss but the degree to which patients are affected differs greatly. To determine if quantitative vibration and thermal testing refined the assessment of severity, 23 familial dysautonomia patients were evaluated by clinical examination, measurements of median, peroneal and sural nerve conduction velocities (NCV), and assessment of vibration thresholds at two body sites and of warm and cold perception thresholds at 6 body sites using the method of limits. Data from 80 age-matched normal individuals provided control data for vibration and temperature thresholds. All familial dysautonomia patients had abnormal thermal thresholds. Vibration perception was abnormal in 20 patients. NCVs were slowed in 8 of 16 patients who agreed to be tested. Abnormalities in thermal thresholds are consistent with the reduction of small nerve fibers in familial dysautonomia Abnormal vibration thresholds might be due to disturbed conduction of vibratory impulse trains and reflect the degree to which the disorder is progressive. Vibration and thermal sensation testing were better accepted and provided more information than NCV regarding severity of disease.

Brainstem reflexes in patients with familial dysautonomia

“…The similar proportion of amplitude decrement for the early and late components, approximately 50%, indicates that both peripheral trigeminal afferents and central pathways within the brainstem are affected in a similar proportion, as occurred with the latencies of these responses. This is in line with pathology samples in FD showing involvement of brainstem reticular formation (Cohen et al, 1955, Brown et al, 1964) and marked reduction in the number of sensory neurons in the trigeminal ganglia (Brown et al, 1964, Aguayo et al, 1971, Pearson et al, 1971, Pearson et al, 1975, Pearson et al, 1978b), as well as the decreased sensory nerve action potentials in the limbs (Hilz et al, 2000). Impairment of the efferent neurons, as suggested by the slightly decreased orbicularis oculi CMAP and masseter EMG amplitudes, is unlikely to fully explain the marked decrease in reflex amplitudes.…”

Disturbances in affective touch in hereditary sensory & autonomic neuropathy type III

“…While hot and cold thresholds, as well as vibration thresholds, were elevated—as described by our laboratory previously (Hilz and Axelrod, 2000)—there were no significant differences in any parameter that could account for the differences in the stroking rating profile between the two groups.…”

Pediatric Autonomic Disorders

“…25 Bone and skin pain are diminished but not absent; sensitivity to visceral pain is intact. Corneal and tendon reflexes are hypoactive, and taste appreciation is diminished, consistent with absence of lingual fungiform papillae.…”