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Xanax Online Abstract - May 23, 2005
A method for determining the magnitude of change across different cognitive functions in clinical trials: the effects of acute administration of two different doses alprazolam.
Snyder PJ, Werth J, Giordani B, Caveney AF, Feltner D, Maruff P.
CNS Early Development, Pfizer Global Research and Development Groton, CT, USA.
While there is no doubt that benzodiazepine administration leads
to transient cognitive impairment in healthy adults, the nature
and magnitude of such impairment has not been well described.
The cognitive effects of a single dose of alprazolam 0.5 and 1
mg were therefore assessed in 36 healthy adults on measures of
psychomotor function, visual attention, working memory, planning
and learning in a double-blind parallel-groups study. Measures
of these different cognitive functions were selected on the basis
of their brevity and because they yielded distributions of performance
data that were without skew, floor or ceiling effects of range
restriction (i.e. normal distributions). With data satisfying
the assumptions for parametric analysis, measures of effect size
could be computed in addition to significance testing, thus allowing
for direct and meaningful comparison between the different performance
measures used. Alprazolam 0.5 mg reduced only the speed of attentional
performance although the magnitude of this reduction was large
(d = 0.8). At 1.0 mg, impairments in psychomotor function, equivalent
to that seen for attentional function at the lower dose, were
observed. In addition, moderate (d approx = 0.5) impairments in
working memory, and learning also became obvious. When considered
together, these results suggest that low-dose alprazolam primarily
alters visual attentional function. At the higher dose psychomotor
functions also become impaired, and it is likely that the combination
of these led to the observed moderate impairments in higher level
executive and memory processes. The current study also illustrates
a method for directly comparing the magnitude of change in cognitive
function between measures with different performance metrics.
Copyright (c) 2005 John Wiley & Sons, Ltd.
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