Is Ross syndrome a dysautonomic disorder only? An electrophysiologic and histologic study.
OBJECTIVE
To define the involvement of peripheral nerve fibers in Ross syndrome.


METHODS
Mechanical pain perception, tactile and thermal thresholds on hand, foot dorsum, thigh, median nerve orthodromic sensory conduction velocity (SCV) and motor conduction velocity (MCV), sural nerve antidromic SCV, peroneal nerve MCV, H-reflex, F-wave, median, tibial nerve somatosensory evoked potentials (SSEPs), perioral, hand CO(2) laser late (LEPs) and ultralate evoked potentials, sympathetic skin response (SSRs), cardiovascular, Minor sweat, silastic imprint, histamine, photopletysmographic and pupil pilocarpine tests, cutaneous innervation immunohistochemical techniques were studied in 3 patients with Ross syndrome.


RESULTS
Quantitative sensory testing showed altered results in patients 1 and 2, and patient 3 had a slight impairment of mechanical pain perception. Nerve conduction, except for a median nerve distal reduction of sensory conduction in patient 1, F-wave and SSEP findings were normal; H-reflex was absent at rest in all patients. Hand LEPs were absent in patient 2, ultralate potentials were absent in patients 1 and 2. Skin biopsy showed a disease duration related reduction of unmyelinated and myelinated sensory fibers and a lack of unmyelinated autonomic fibers in all patients.


CONCLUSIONS
Our data suggest that Ross syndrome is a degenerative disorder involving progressive sudomotor fibers, and then epidermal sensory unmyelinated and myelinated fibers.
Perretti
A
A
Department of Neurological Sciences, University of Naples 'Federico II', Via Sergio Pansini 5, Naples, Italy.
Nolano
M
M
De Joanna
G
G
Tugnoli
V
V
Iannetti
G
G
Provitera
V
V
Cruccu
G
G
Santoro
L
L
D000328:Adult; D001706:Biopsy; D001794:Blood Pressure; D004594:Electrophysiology; D005073:Evoked Potentials, Somatosensory; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D007007:Hypohidrosis / Q000473:pathology* / Q000503:physiopathology*; D007834:Lasers; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009431:Neural Conduction; D011680:Pupil; D012119:Respiration; D012867:Skin / Q000473:pathology / Q000503:physiopathology; D014636:Valsalva Maneuver