A study on attention function in patients with mild Alzheimer's disease

Objective: To determine whether the sustained, selective and diverted attention functions are affected in patients with mild Alzheimer's disease (AD). Methods: Several tasks designed to test the attention functions on the computer were performed in patients with mild AD as well as elderly controls: Continuous Performance Task (CPT) for assessing sustained attention function, simplified Stroop task for selective attention function, dual task for diverted attention function. Results: In CPT test, mild AD patients responded more slowly ((539.29 ± 103.86) ms vs (458.47 ± 40.87) ms, P < 0.01) and missed more targets (4.08% (3.13%, 13.64%) vs 0.91% (0.60%, 1.90%), P < 0.01). The abnormality rate increased along with time (6.09% (4.87%, 20.73%) vs 2.43% (2.43%, 3.04%), P < 0.01). In Stroop test, the mild AD patients responded more slowly ((579.19 ± 89.93) ms vs (486.75 ± 51.58) ms, P < 0.01) and showed greater Stroop effect (see table 4, table 5, P < 0.01), making a higher error rate under conflicting condition (13.33% (8.75%, 17.50%) vs 2.92% (1.67%, 3.96%), P < 0.01). Mild AD patients also did worse in dual task than control subjects (P < 0.01). The abnormality rates in CPT and Stroop tests were higher than that in dual task test. Conclusion: In mild AD patients, their attention functions are impaired among which selective and sustained attention function are more affected.