Visuospatial working memory dysfunction from tapping span test as a diagnostic tool for patients with mild posterior cortical atrophy

Michitaka Funayama,Yoshitaka Nakagawa,Hiroaki Kawashima,Kosaku Sunagawa,Asuka Nakajima,Taketo Takata,Masaru Mimura

doi:10.1038/s41598-021-90159-w

Abstract

Posterior cortical atrophy is a rare degenerative condition with prominent visuospatial dysfunction which commonly occurs between ages 50 and 65. A diagnosis of mild posterior cortical atrophy sometimes challenging and can be delayed because there are currently no established neuropsychological examination methods that can easily be used in clinical settings. In this study, we examined whether the tapping span test is a potential diagnostic tool for posterior cortical atrophy and what impairment the tapping span test is indicative of in this condition. Eight patients with mild posterior cortical atrophy were recruited. Age- and severity-matched individuals with amnesic Alzheimer’s disease (n = 9) were also recruited as a control group. The participants were subjected to the tapping span test and several visuospatial working memory tests. The results of the tapping span and visuospatial working memory tests were worse for the posterior cortical atrophy group when compared with the control group. The results from the tapping span tests were strongly correlated with those from the visuospatial working memory tests. The tapping span test is a simple and potentially useful diagnostic tool for patients with mild posterior cortical atrophy, as it reflects visuospatial working memory function.

Highlights

Posterior cortical atrophy is a rare degenerative condition with prominent visuospatial dysfunction which commonly occurs between ages 50 and 65
We examined whether the tapping span test16,17—a simple neuropsychological test that has been widely used in clinical settings and takes only a few minutes to complete without computers—is a potential diagnostic indicator of mild posterior cortical atrophy
Two patients with posterior cortical atrophy declined to perform the Japanese version of the Wechsler Adult Intelligence Scale, the difference in performance between verbal comprehension and perceptual organization was substantial in six patients with posterior cortical atrophy (Mann–Whitney U-test, p < 0.01), which reflects their severe visuospatial dysfunction

Summary

Introduction

Posterior cortical atrophy is a rare degenerative condition with prominent visuospatial dysfunction which commonly occurs between ages 50 and 65. The tapping span test is a simple and potentially useful diagnostic tool for patients with mild posterior cortical atrophy, as it reflects visuospatial working memory function. Posterior cortical atrophy is a rare degenerative condition which commonly occurs between ages 50 and 65 and is characterized mainly by visuospatial d ysfunction[1,2] This condition is under-recognized and u nderdiagnosed[1,2,3] because a diagnosis of posterior cortical atrophy is sometimes challenging among assessments of neurodegenerative conditions[3], in particular, of the mild form and can be delayed because of the rarity of this condition and because, aside from visuospatial dysfunction, patients with mild posterior cortical atrophy function almost normally with respect to memory, language, and behavior and maintain a relatively preserved motivation and insight[3,4,5,6,7]. We examined whether the tapping span test16,17—a simple neuropsychological test that has been widely used in clinical settings and takes only a few minutes to complete without computers—is a potential diagnostic indicator of mild posterior cortical atrophy. We analyzed whether the results from the tapping span test reflect visuospatial working memory function for patients with posterior cortical atrophy

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