|
R.J. Servatius, J.E.Ottenweller, B.H. Natelson, S.D.
Drastal,
M.T. Bergen, C.A. Pollet and L.A.Tiersky
Department of Veterans Affairs, New Jersey Health Care
System, East Orange, NJ
Department of Neuroscience, New Jersey Medical School, Newark, NJ
Veterans of the Persian Gulf War (PGW) have registered complaints
of impaired memory and reasoning. Here, we assessed acquisition of the
classically conditioned eyeblink response, a test of new motor learning,
in PGW veterans. A delay-type conditioning paradigm was used, that is,
the 500-ms, 800-Hz pure tone conditioned stimulus coterminated with a
50-ms airpuff unconditioned stimulus. Eyeblink conditioned responses (CRs)
were determined from eyelid electromyographic activity. Subjects were
22 PGW veterans (18 on the Registry) and 11 civilian controls. Acquisition
of the classically conditioned eyeblink response was impaired in PGW veterans
compared to civilians. Of the PGW veterans, 12 (54 %) failed to reach
a criterion of 8 CRs out of 12 consecutive trials. In contrast, only 1
(12%) of the civilians failed to reach the criterion. In our PGW veteran
sample, 13 (59%) of the veterans registered subjective complaints of learning,
memory or concentration difficulties. Of the 12 veterans who failed to
reach the criterion, 9 (75%) veterans registered memory complaints. Of
the 10 veterans who reached the criterion, 4 (40%) veterans registered
memory complaints. These preliminary data suggest that acquisition of
the classically conditioned eyeblink response is impaired in PGW veterans.
Moreover, the eyeblink paradigm may be a sensitive index of the subjective
cognitive complaints of PGW veterans.
KEYWORDS: Learning, Memory, Eyeblink
This work support by DVA Medical Research, the DVA Medical
Center for Environmental Hazards Research, and NASA Experimental Research
funds.
|
