Blink reflex discloses CNS dysfunction in neurologically asymptomatic patients with systemic sclerosis.
OBJECTIVE
To investigate trigeminal-nerve, brain-stem, and brain function, in order to disclose a possible nervous system involvement in neurologically asymptomatic systemic sclerosis (SSc) patients.


METHODS
Using a standard electromyographic (EMG) technique, we recorded the early (R1) and late (R2) components of the blink reflex in 35 SSc patients with no history or signs of cranial-nerve impairment and 20 control subjects. SSc patients were classified as limited or diffuse SSc and also evaluated for disease duration, autoantibody pattern (ANA, ACA, Scl70) and skin score (by Rodnan modified method).


RESULTS
Whereas no SSc patients had an abnormal R1, six (18%) had delayed R2 responses. We found no correlation between R2 latency and clinical or laboratory data.


CONCLUSIONS
Whereas previous studies reported both R1 and R2 abnormalities (reasonably due to trigeminal neuropathy) in symptomatic SSc patients, we found selective abnormalities of the R2 components in asymptomatic patients. The selective R2 abnormality is secondary to a central dysfunction, either because of a direct impairment of the polysynaptic circuits in the medulla, or because of a decreased cortico-reticular drive on these circuits. The lack of overt trigeminal symptoms in our patients favours a suprasegmental dysfunction, possibly due to microvascular lesions disseminated in the subcortical white matter.
Casale
Roberto
R
Department of RRF and Service of Clinical Neurophysiology, Salvatore Maugeri Foundation, IRCCS Rehabilitation Institute of Montescano, Via per Montescano, 27040 Montescano, Italy.
Frazzitta
Giuseppe
G
Fundarò
Cira
C
Balbi
Pietro
P
Del Rosso
Angela
A
Bertinotti
Luca
L
Matucci-Cerinic
Marco
M
D000328:Adult; D000368:Aged; D001767:Blinking / Q000502:physiology*; D002493:Central Nervous System Diseases / Q000503:physiopathology*; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000503:physiopathology*; D018709:Statistics, Nonparametric