Chapter 8, Problem 79P

A study was performed looking at the effect of physical activity on cognitive function among adults at high risk for Alzheimer’s disease (Lautenschlager et al. [14]). There were 170 eligible subjects randomly assigned to either an exercise intervention (exercise group) or a control intervention (control group). The subjects were followed at 6-month intervals up to 18 months of follow-up. The primary assessment scale was the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog). The results at 18 months of follow-up among participants with mild cognitive impairment are given in Table 8.23.

Table 8.23 Mean difference from baseline (18-month score minus baseline score) among participants with mild cognitive impairment in the ADAS-Cog score^*

^*A negative change indicates improvement since high values on the testindicate worse cognitive function

What test can be performed to compare the mean change in the two groups at 18 months?