Utoomprurkporn Nattawan, Hardy Chris J D, Stott Joshua, Costafreda Sergi G, Warren Jason, Bamiou Doris Eva
UCL Ear Institute, Faculty of Brain Science, University College London, London, United Kingdom.
Department of Otolaryngology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
J Am Acad Audiol. 2020 Oct;31(9):646-655. doi: 10.1055/s-0040-1718700. Epub 2020 Dec 9.
Patients with dementia commonly have problems processing speech in the presence of competing background speech or noise. This difficulty can be present from the very early stages of dementia, and may be a preclinical feature of Alzheimer's disease.
This study investigates whether people with dementia perform worse on the dichotic digit test (DDT), an experimental probe of speech processing in the presence of competing speech, and whether test performance may predict dementia onset.
Systematic review and meta-analysis.
A literature search was conducted in Medline, Embase, Scopus, and Psycinfo. We included (1) studies that included people with a diagnosis of dementia and a healthy control group with no cognitive impairment; (2) studies that reported results from a DDT in a free-recall response task; and (3) studies that had the dichotic digit mean correct percentage score or right-ear advantage, as outcome measurements.
People with dementia had a lower DDT total score, with a pooled mean difference of 18.6% (95% confidence interval [CI]: 21.2-15.9). Patients with dementia had an increased right-ear advantage relative to controls with a pooled difference of 24.4% (95% CI: 21.8-27.0).
The DDT total scores are lower and the right-ear advantage increased in cognitively impaired versus normal control participants. The findings also suggest that the reduction of dichotic digit total score and increase of right-ear advantage progress as cognitive impairment increases. Whether abnormalities in dichotic digit scores could predict subsequent dementia onset should be examined in further longitudinal studies.
痴呆患者在存在竞争性背景语音或噪音的情况下，通常在处理语音方面存在问题。这种困难在痴呆的早期阶段就可能出现，并且可能是阿尔茨海默病的临床前特征。
本研究调查痴呆患者在双耳数字试验（DDT）中表现是否更差，DDT是一种在存在竞争性语音时对语音处理进行实验性探测的方法，以及测试表现是否可以预测痴呆的发病。
系统评价和荟萃分析。
在Medline、Embase、Scopus和Psycinfo中进行文献检索。我们纳入了：（1）包括痴呆诊断患者和无认知障碍的健康对照组的研究；（2）报告自由回忆反应任务中DDT结果的研究；（3）以双耳数字平均正确百分比得分或右耳优势作为结局测量指标的研究。
痴呆患者的DDT总分较低，合并平均差异为18.6%（95%置信区间[CI]：21.2 - 15.9）。与对照组相比，痴呆患者的右耳优势增加，合并差异为24.4%（95% CI：21.8 - 27.0）。
与正常对照参与者相比，认知受损者的DDT总分更低，右耳优势增加。研究结果还表明，随着认知障碍的增加，双耳数字总分的降低和右耳优势的增加也在进展。双耳数字得分异常是否可以预测随后的痴呆发病，应在进一步的纵向研究中进行检验。
