Purchase this article with an account.
M.L. Moster, O.S. Jørgensen, D.S. Woodruff-Pak; Eyeblink Classical Conditioning Predicts Apolipoprotein 4 Status . Invest. Ophthalmol. Vis. Sci. 2003;44(13):1945.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:. Overrepresentation of the apolipoprotein (APOE) є4 allele is associated with an increased risk for developing sporadic Alzheimer's disease (AD) and is also associated with impaired cognitive performance. Identifying a group of individuals carrying the є4 allele increases the probability that some members of the group will have AD, but it is not possible to predict whether or not an individual in any group will develop symptoms of AD on the basis of APOE genotype. Eyeblink classical conditioning is a measure that has utility in detecting individuals with AD. In four separate prior studies, the sensitivity of eyeblink conditioning (400 ms delay procedure) ranged from 86-100%, and the specificity was around 80%. In this study the aim was to compare eyeblink conditioning performance in healthy older adults in relation to APOE status. Methods:28 community-residing older adult participants were tested for 80 trials in the 400 ms delay eyeblink conditioning procedure with a 1 KHz tone conditioned stimulus (CS) presented for 500 ms and followed 400 ms after CS onset with a 5 psi 100 ms corneal airpuff. Conditioned responses (CRs) were scored when the eyeblink occurred 150-399 ms after CS onset indicating that the subject had learned to blink to the CS. APOE status was determined from samples collected with a mouth swab. Results:From a total of 56 alleles (2 for each participant), there was an є4 allele in 3 different subjects. Comparison of eyeblink conditioning scores indicated a significant effect even in this small sample. Each of the 3 є4 carriers had eyeblink conditioning scores in the AD range (below 25% CRs). Mean CR% for є4 carriers was 14.0 (s.d. = 6.7). Mean CR% for the rest of the sample was 28.4 (s.d. = 19.8). Statistical comparison of the scores from subjects with and without an є4 allele were significant (t  = 2.60, p = 0.033). Poor eyeblink conditioning was associated with the presence of an є4 allele, and the presence of an є4 allele is associated with greater risk for AD. Conclusions: A simple test of associative learning using the eyeblink may have utility in identifying individuals at risk for AD.
This PDF is available to Subscribers Only