Preserved absolute pitch and musical working memory in posterior cortical atrophy.

Background: The cognitive organisation of working memory for nonverbal sounds and the unusual musical ability of absolute pitch is poorly understood. We recently had the opportunity to investigate this in a musician with absolute pitch who developed posterior cortical atrophy (PCA), the canonical 'visual variant' of Alzheimer's disease. Method: We studied a 59 year old professional pianist, PA, known premorbidly to have absolute pitch and fulfilling diagnostic criteria for PCA, in comparison to five healthy age‐matched female musicians (three with absolute pitch, two without). Each participant completed the melodic organisation (scale, contour, interval) and rhythm subtests of the Montreal Battery for Evaluation of Amusia (MBEA), an assessment of absolute pitch ability, a standard test of auditory verbal working memory (digit span), an equivalent working memory test for spoken letters and a series of bespoke musical working memory tasks assessing forward and reverse span for pitch sequences, rhythmic sequences and sequences combining these two dimensions. Result: PA had reduced digit span and letter span relative to healthy musician controls, as anticipated from her diagnosis. However, she had retained absolute pitch and performed normally on MBEA subtests assessing pitch and rhythm patterns and within the healthy musician range on the bespoke tests of pitch and rhythm working memory. Across musical working memory tests, PA showed a profile similar to healthy musician controls with absolute pitch: all performed better on the pitch working memory task than other musical working memory tasks. On the pitch working memory test, PA performed better than the healthy musicians without absolute pitch, all of whom performed worse on the pitch task than other musical working memory tasks. Conclusion: Our findings suggest that absolute pitch may be preserved and continue to support musical working memory (despite impaired verbal working memory) in PCA. This study has implications for our understanding of the cognitive and neural mechanisms of absolute pitch and nonverbal auditory working memory. [ABSTRACT FROM AUTHOR]