Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA.
Department of Clinical Neurological Sciences, Western University and London Health Sciences Center, London, ON, Canada.
Mult Scler. 2022 Jun;28(7):1101-1111. doi: 10.1177/13524585211049397. Epub 2021 Oct 6.
The Symbol Digit Modalities Test (SDMT) is increasingly utilized in clinical trials. A SDMT score change of 4 points is considered clinically important, based on association with employment anchors. Optimal thresholds for statistically reliable SDMT changes, accounting for test reliability and measurement error, are yet to be applied to individual cases.
The aim of this study was to derive a statistically reliable marker of individual change on the SDMT.
This prospective, case-control study enrolled 166 patients with multiple sclerosis (MS). SDMT scores at baseline, relapse, and 3-month follow-up were compared between relapsing and stable patient groups. Using data from the stable group and three previously published studies, candidate thresholds for reliable decline were calculated and validated against other tests and a clinically meaningful anchor-cognitive relapse.
Candidate thresholds for reliable decline at the 80% confidence level varied between 6 and 11 points. An SDMT change of 8 or more raw score points was deemed to offer the best balance of discriminatory power and external validity for estimating cognitive decline.
This study illustrates the feasibility and usefulness of reliable change methodology for identifying statistically meaningful cognitive decline that could be implemented to identify change in individual patients, for both clinical management and clinical trial outcomes.
符号数字模态测试（SDMT）在临床试验中越来越多地被使用。基于与就业指标的关联，SDMT 分数变化 4 分被认为具有临床意义。考虑到测试可靠性和测量误差，统计学上可靠的 SDMT 变化的最佳阈值尚未应用于个体病例。
本研究旨在确定 SDMT 个体变化的统计学可靠标志物。
这项前瞻性病例对照研究纳入了 166 名多发性硬化症（MS）患者。比较复发组和稳定组患者在基线、复发和 3 个月随访时的 SDMT 评分。利用稳定组和之前三项研究的数据，计算可靠下降的候选阈值，并针对其他测试和临床有意义的认知复发指标进行验证。
80%置信水平下可靠下降的候选阈值在 6 到 11 分之间变化。SDMT 变化 8 个或更多原始分数点被认为是估计认知下降的鉴别力和外部有效性的最佳平衡点。
本研究说明了可靠变化方法在确定具有统计学意义的认知下降方面的可行性和实用性，可用于识别个体患者的变化，以便进行临床管理和临床试验结果的评估。
