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Abstract:
n ERP component, the auditory mismatch negativity (MMN), was
used as a probe to evaluate changes in the transient memory on
which it depends. Alzheimers patients (M= 74 years) and elderly
controls (M= 74 years) were presented with standard auditory
stimuli in trains of eight tones (1000Hz, 50ms duration, 500ms
interstimulus interval) with either a 1s or 8s intertrain interval
(ITI). Occasionally, the first stimulus of a train was replaced
with a 1200 Hz tone (deviant). MMN was recorded while subjects
watched a silent movie and ignored the stimuli. On completion of
MMN recordings, subjects were instructed to make a speeded button
response each time they heard the deviant stimulus. Response times
were longer in the 8s condition, and did not differ between groups.
Accuracy for both groups was near 100%. The deviant stimulus
elicited an MMN, of similar amplitude for both groups, only in the
1s condition. These results support the view that the integrity of
the auditory sensory memory system on which the MMN depends is not
compromised during the early stages of Alzheimers Disease in its
efficacy or its duration. Helen Gaeta, Ph.D. Cognitive
Electrophysiology Laboratory NYSPI, Box# 6 1051 Riverside Drive New
York, NY, 10032 USA PH: (212) 543-5669 Fax: (212) 543-6002 email:
gaetahe@pi.cpmc.columbia.edu
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