Abstract

Dementia is characterized by the deterioration of working memory (WM). The backward digit span (DS) task and reading span test (RST) are measures of WM. DS task and RST have not been directly compared in assessing dementia. This study aimed to compare the performance of individuals with dementia in forward and backward DS tasks to that in RST. We investigated the ability of forward/backward DS tasks to discriminate dementia severity. Forward/backward DS tasks and RST were performed in 15 elderly Japanese individuals with dementia. Twenty-six and 20 elderly individuals for the DS task and RST, respectively, were included as controls. Clinical Dementia Rating scale (CDR) was used to evaluate dementia severity. DS task scores were significantly correlated with RST scores. Both types of DS tasks correlated with RST, only the RST distinguished dementia severity based on CDR. Our findings indicate that the backward DS task may detect WM decline in dementia, but the RST is more suitable for assessing dementia severity. The backward DS task may be an effective screening measure for dementia signs in the elderly and may be used to identify patients requiring further assessments such as the RST to evaluate dementia severity based on WM performance.

摘要

痴呆症的特点是工作记忆（WM）恶化。向后数字跨度（DS）任务和阅读跨度测试（RST）是WM的测量。DS 任务和 RST 在评估痴呆症方面尚未进行直接比较。本研究旨在比较痴呆症患者在前向和后向 DS 任务中的表现与 RST 中的表现。我们研究了前向/后向 DS 任务区分痴呆严重程度的能力。对 15 名患有痴呆症的日本老年人进行了前向/后向 DS 任务和 RST。分别进行 DS 任务和 RST 的 26 名和 20 名老年人作为对照。临床痴呆评定量表（CDR）用于评估痴呆的严重程度。DS 任务得分与 RST 得分显着相关。两种类型的 DS 任务都与 RST 相关，只有 RST 根据 CDR 区分痴呆的严重程度。我们的研究结果表明，后向 DS 任务可以检测痴呆症中 WM 的下降，但 RST 更适合评估痴呆症的严重程度。后向 DS 任务可能是老年人痴呆体征的有效筛查措施，并且可用于识别需要进一步评估的患者，例如基于 WM 表现的 RST 评估痴呆严重程度。