Changes in memory performance are one of the hallmark symptoms of mild cognitive impairment and are affected by healthy aging as well. Pattern separation, which refers to the process of orthogonalizing overlapping inputs into distinct memory representations, may be a sensitive marker of these memory changes. In this report, the authors describe a Behavioral Pattern Separation Task which reveals age-related changes in pattern separation performance. They report age-related decline in pattern separation in healthy adults, ranging from ages 20 to 89. Individuals aged 60 and older were classified into two groups, Aged Unimpaired and Aged Impaired based on their delayed word recall performance. Aged Impaired adults are clinically normal and do not present with memory complaints, but their pattern separation performance was impaired relative to young adults and Aged Unimpaired adults. By contrast, recognition performance was intact in both Aged Unimpaired and Aged Impaired individuals. Individuals diagnosed with mild cognitive impairment demonstrated worse performance than age-matched controls in both pattern separation and recognition memory performance. The authors suggest that their Behavioral Pattern Separation task may provide a sensitive measure for observing changes in memory performance across the lifespan and could be useful for the early detection of memory impairments that lead to mild cognitive impairment.
Stark SM, Yassa MA, Lacy JW, Stark CE : A task to assess behavioral pattern separation (BPS) in humans : Data from healthy aging and mild cognitive impairment. Neuropsychologia [Epub ahead of print, Jan. 9, 2013; doi: 10.1016/j.neuropsychologia.2012.12.014 ].