Gehrig Johannes, Bergmann Heinrich Johannes, Fadai Laura, Soydaş Dilara, Buschenlange Christian, Naumer Marcus J, Kaiser Jochen, Frisch Stefan, Behrens Marion, Foerch Christian, Yalachkov Yavor
Department of Neurology, University Hospital Frankfurt, Frankfurt, Germany.
Institute of Medical Psychology, Goethe-University, Frankfurt, Germany.
Front Neurol. 2022 Feb 14;13:838178. doi: 10.3389/fneur.2022.838178. eCollection 2022.
Standardized neuropsychological testing serves to quantify cognitive impairment in multiple sclerosis (MS) patients. However, the exact mechanism underlying the translation of cognitive dysfunction into difficulties in everyday tasks has remained unclear. To answer this question, we tested if MS patients with intact vs. impaired information processing speed measured by the Symbol Digit Modalities Test (SDMT) differ in their visual search behavior during ecologically valid tasks reflecting everyday activities.
Forty-three patients with relapsing-remitting MS enrolled in an eye-tracking experiment consisting of a visual search task with naturalistic images. Patients were grouped into "impaired" and "unimpaired" according to their SDMT performance. Reaction time, accuracy and eye-tracking parameters were measured.
The groups did not differ regarding age, gender, and visual acuity. Patients with impaired SDMT (cut-off SDMT-z-score < -1.5) performance needed more time to find and fixate the target ( = 0.006). They spent less time fixating the target ( = 0.042). Impaired patients had slower reaction times and were less accurate (both = 0.0495) even after controlling for patients' upper extremity function. Exploratory analysis revealed that unimpaired patients had higher accuracy than impaired patients particularly when the announced target was in unexpected location ( = 0.037). Correlational analysis suggested that SDMT performance is inversely linked to the time to first fixation of the target only if the announced target was in its expected location ( = -0.498, = 0.003 vs. = -0.212, = 0.229).
Dysfunctional visual search behavior may be one of the mechanisms translating cognitive deficits into difficulties in everyday tasks in MS patients. Our results suggest that cognitively impaired patients search their visual environment less efficiently and this is particularly evident when top-down processes have to be employed.
标准化神经心理学测试有助于量化多发性硬化症（MS）患者的认知障碍。然而，认知功能障碍转化为日常任务困难的确切机制仍不清楚。为了回答这个问题，我们测试了通过符号数字模式测验（SDMT）测量信息处理速度正常与受损的MS患者在反映日常活动的生态有效任务中的视觉搜索行为是否存在差异。
43例复发缓解型MS患者参加了一项眼动追踪实验，该实验包括一项带有自然图像的视觉搜索任务。根据患者的SDMT表现将其分为“受损组”和“未受损组”。测量反应时间、准确性和眼动追踪参数。
两组在年龄、性别和视力方面无差异。SDMT表现受损（SDMT-z分数临界值＜-1.5）的患者找到并注视目标需要更多时间（P = 0.006）。他们注视目标的时间较少（P = 0.042）。即使在控制了患者的上肢功能后，受损患者的反应时间较慢且准确性较低（两者P均 = 0.0495）。探索性分析显示，未受损患者的准确性高于受损患者，尤其是当宣布的目标位于意外位置时（P = 0.037）。相关分析表明，仅当宣布的目标位于预期位置时，SDMT表现与首次注视目标的时间呈负相关（P = -0.498，P = 0.003，而P = -0.212，P = 0.229）。
功能失调的视觉搜索行为可能是MS患者将认知缺陷转化为日常任务困难的机制之一。我们的结果表明，认知受损的患者对视觉环境的搜索效率较低，当必须采用自上而下的过程时，这一点尤为明显。
