VANCOUVER—Cholinesterase inhibitor treatment in patients with mild Alzheimer’s disease may lead to greater improvement in cognitive performance than cholinesterase inhibitor treatment in patients with moderate Alzheimer’s disease, researchers reported at the 2012 Alzheimer’s Association International Conference.
“Death of cholinergic neurons in patients with Alzheimer’s disease correlates with severity of cognitive impairment,” said Sarah Wakefield, doctoral student at the University of Sheffield in the United Kingdom, and colleagues.
The researchers sought to predict patients’ response to cholinesterase inhibitor treatment during the short and long term, as well as describe differences in how patients with mild Alzheimer’s disease respond to treatment, compared with those with moderate Alzheimer’s disease.
Among the 56 patients who were included in the study, 17 had mild Alzheimer’s disease along with Mini-Mental State Examination (MMSE) scores of 24 or higher, and 39 patients had moderate Alzheimer’s disease and MMSE scores between 17 and 23.
Short- and Long-Term Assessment
The investigators compared MMSE scores before and after cholinesterase inhibitor treatment and used those scores to determine the percentage of recovery. Short-term follow-up was conducted for a mean of four months, and the mean long-term follow-up was 11 months.
At first follow-up, the overall group of patients with Alzheimer’s disease had a 6.93% recovery, compared with baseline, and the same group showed a 1.00% recovery, compared with baseline at second follow-up.
Ms. Wakefield and her colleagues also categorized the overall patient sample into responder and nonresponder subgroups based on their percentage of recovery in MMSE score. Compared with the nonresponder subgroup, the responder subgroup had a substantially higher percentage of recovery at first and second follow-up.
Further subgrouping of the study sample created four groups based on patients’ first and second follow-up responses. For example, some patients responded at first and second follow-up, some did not respond at either follow-up, and some had a response followed by a nonresponse and vice versa.
Extent of Recovery After Cholinesterase Inhibitor Treatment
According to the investigators, patients in the group that responded at both follow-ups had the greatest percentage of recovery. However, patients who had either an early or late response still had MMSE scores that were higher than baseline, which indicates that even patients without consistent positive responses to cholinesterase inhibitor treatment still benefit from the treatment, compared with those who show no response at first and second follow-up.
The study authors also examined disease severity, finding that patients with mild Alzheimer’s disease had a higher average recovery (55%) in response to cholinesterase inhibitor treatment than patients with moderate Alzheimer’s disease (25%). Nonresponders with mild Alzheimer’s disease also had a more modest decrease in performance than nonresponders with moderately severe Alzheimer’s disease, the researchers noted.
“Even in the absence of a detectable response, performance of patients in the mild stage appears to decrease to a lesser extent than that observed in nonresponders who are in the moderate stage of the disease, suggesting an effect on progression of the disease in addition to alleviation of symptoms,” the study authors concluded.
—Lauren LeBano