Bj. Sahakian et Jt. Coull, TETRAHYDROAMINOACRIDINE (THA) IN ALZHEIMERS-DISEASE - AN ASSESSMENT OF ATTENTIONAL AND MNEMONIC FUNCTION USING CANTAB, Acta neurologica Scandinavica, 88, 1993, pp. 29-35
A placebo-controlled cross-over trial (n=89) investigated the use of a
chronic dose of the cholinesterase inhibitor THA, as a treatment for
dementia of the Alzheimer type (DAT). Effects on both subjective clini
cal rating scales and objective computerised tests were assessed. In r
egard to the former, analysis of the three main clinical outcome measu
res showed statistically significant effects of the drug on the Mini-M
ental State Examination (MMSE) and the Abbreviated Mental Test Score (
AMTS), but not on the Activities of Daily Living scale (ADL). Using th
e objective computerised CANTAB tests, sensitive to specific aspects o
f memory and attention, evidence was found for improvements in attenti
onal function rather than memory, in patients with mild to moderate DA
T. Although these improvements were significant, they were small and r
estricted to certain tests of attentional function. Nevertheless, they
add to the growing body of evidence that the cholinergic system is in
volved in the control of attentional processes; and are substantiated
by the findings of a second study examining the effects of an acute do
se of nicotine on attentional and mnemonic performance in patients wit
h DAT. This study found significant improvements in cognitive performa
nce in patients receiving nicotine, in objective tests of attention bu
t not of short-term memory. These data will clearly provide important
comparative data for future investigations of putative cognitive enhan
cing drugs in DAT sufferers.