Supplementary Material for: The Single-Matrix Digit Cancellation Test (SMDCT), a screener for selective attention deficits: standardization in an Italian population sample and clinical usability in acute stroke patients

Introduction. This study aimed at validating and providing Italian norms for the Single-Matrix Digit Cancellation Test (SMDCT), a cancellation task to screen for selective attention deficits, as well as providing clinical usability evidence for it in acute stroke patients. Methods. The SMDCT stimulus is a specular, 4-quadrant, horizontally oriented matrix, across which target distribution is homogeneous. Both Accuracy (-A) and Time (-T) outcomes were computed. N=263 healthy participants (HPs) and N=76 acute stroke patients were recruited. N=108 HPs also underwent the Mini-Mental State Examination, Frontal Assessment Battery (FAB) and Trail-Making Test (TMT), whilst patients were further assessed via the Mental Performance in Acute Stroke (MEPS). Regression-based norms were derived (Equivalent Scores). Construct and factorial validity, as well as case-control discrimination, were tested. Results. The matrix was underpinned by a two-component structure reflecting left and right hits. The SMDCT-T and -A were associated with TMT and FAB scores, respectively. Education predicted the SMDCT-A/-T, whereas age the SMDCT-T only. In patients, the SMDCT converged with the MEPS, also accurately discriminating them from HPs. An index of right-left difference differentiated right- from left-damaged patients. Conclusions. The SMDCT is a valid and normed screener for selective attention deficits, encompassing measures of both accuracy and time, whose adoption is encouraged in acute stroke patients. Relatedly, the horizontal disposition of its matrix does allow for the qualitative report of either leftwards of rightwards biases due to underlying visual or attentional-representational deficits in this population.

引言。本研究旨在验证单矩阵数字划消测验（Single-Matrix Digit Cancellation Test, SMDCT）并建立其意大利常模——该划消任务用于筛查选择性注意缺陷，同时为其在急性卒中患者中的临床应用可行性提供实证依据。
方法。单矩阵数字划消测验的刺激材料为镜面对称、分为4个象限的水平排列矩阵，靶刺激在矩阵内分布均匀。本研究计算了正确率（-A）与完成时间（-T）两项指标。共招募263名健康受试者（healthy participants, HPs）与76名急性卒中患者。其中108名健康受试者同时完成了简易精神状态检查表（Mini-Mental State Examination）、额叶评估量表（Frontal Assessment Battery, FAB）与连线测验（Trail-Making Test, TMT）；患者则进一步接受了急性卒中精神功能评估量表（Mental Performance in Acute Stroke, MEPS）评估。本研究基于回归分析推导了常模（等值分数，Equivalent Scores），并检验了其结构效度、因子效度以及病例-对照区分能力。
结果。该测验的作答数据可拆解为反映左侧与右侧命中情况的双因子结构。单矩阵数字划消测验的完成时间（SMDCT-T）与正确率（SMDCT-A）分别与连线测验（TMT）得分及额叶评估量表（FAB）得分显著相关。受教育程度可同时预测SMDCT-A与SMDCT-T得分，而年龄仅能预测SMDCT-T得分。在患者群体中，单矩阵数字划消测验结果与急性卒中精神功能评估量表（MEPS）结果具有良好的一致性，且能够准确区分患者与健康受试者。左右侧差异指数可有效区分右侧脑损伤与左侧脑损伤患者。
结论。单矩阵数字划消测验是一款经常模化且有效的选择性注意缺陷筛查工具，涵盖正确率与完成时间两项评估指标，推荐在急性卒中患者中推广应用。此外，其矩阵的水平排列设计，可针对该群体因潜在视觉或注意-表征缺陷导致的左侧或右侧偏向，开展定性分析。