Learning and recall in subjects at genetic risk for Alzheimer's disease.

Deficits in delayed recall of learned information may be an early marker of Alzheimer's disease (AD). The apolipoprotein E E4 allele and a positive family history (FH) are both genetic risk factors for AD. The authors cross-sectionally compared performance on the California Verbal Learning Test (CVLT) in 153 prospectively recruited normal elderly subjects (mean age 67 years, mean MMSE=28) stratified by genetic risk into four groups (E4+/FH+, E4+/FH-, E4-/FH+, E4-/FH-). Neither FH nor E4 status affected performance, except on List B (a distraction word list), on which the FH+ group performed worse. The high-risk group (E4+/FH+) also performed worse on List B than the low-risk group (E4-/FH-) but did not differ on other measures. Memory impairments associated with genetic or family history risk may not manifest until the person is much closer to the onset age of AD.