視覺誘發電位檢查在認知功能障礙學生視力檢測之試驗性探究

VEP Examination of Students with Cognitive Impairment

本研究目的在透過視覺誘發電位檢查，分析認知功能缺損學生視力檢測的可行性。除 比較一般人在不同的矯正視力下，PVEP 與FVEP 檢查結果之差異外，同時建構VEP 數值 與視力值間的相關；另針對認知功能缺損學生，依VEP 之檢測結果，進一步分析其VEP 表現與一般人的異同。本研究分為兩個階段，第一階段取正常研究對象21 人42 眼，第二 階段則為認知功能缺損學生5 人。研究的資料包含量化的檢測資料與可判讀的圖表。第一 階段(1)年齡分組在PVEP 與FVEP 的振幅檢測中未達顯著差異，但年輕組反應有優於年長 組的趨勢；(2)不同屈光度在PVEP 與FVEP 的振幅檢測中未達顯著差異；然卻有屈光度愈 高潛伏期愈長的表現；(3)性別在PVEP 的振幅檢測中有顯著差異；而在FVEP 中未達顯著， 但仍出現女性反應優於男性的趨勢；(4)PVEP 幅度反應隨視力值的變化而有顯著的改變， 視力值越好幅度越高，尤以圖形64*64 最為明顯；(5)PVEP 與FVEP 的相關分析顯示，在 振幅的比較上仍以圖形64*64 及第二次的閃光幅度之間有較高的信度。第二階段(1)認知功 能障礙學生的視力值可以第一階段的迴歸公式套用，但仍須經醫療與教育人員的綜合研 判；(2)特殊個案應由家長或熟悉校護陪同進行VEP 檢測，避免因陌生而產生偏差；(3)VEP 檢測前應由經驗光師進行屈光矯正與功能性視覺評估。最後根據本研究之研究結果與研究 限制，提出對教育行政機關、學校、特教老師、特殊學生家庭、醫療相關人員及未來研究 之建議。

Purpose: The purpose of this study is to investigate and analyze the role of visual evoked potential (VEP) parameters in visual function in students with cognitive impairment (CI). Methods: In general， norm-referenced data were collected under different visual acuity conditions (uncorrected， 0.3， 0.8， 1.0). In stage one， twenty-one adults aged from 18 to 29 years with myopia and astigmatism but no ocular or systemic diseases participated in the study. In stage two， 5 students with CI identified through the educational system also entered the study. Examination included testing of visual acuity (VA)， intra-ocular pressure， refraction for spherical equivalent， and both PVEP and FVEP. In addition to statistical correlation of each parameter with CI visual functions， independent t-test， ANOVA， and modulators of VA were analyzed through linear regression analysis that included cumulative adjusted R2 values. Results: Stage one: (1) No significant difference between PVEP responses as a function of age; although (2) PVEP and FVEP amplitude responses in females were both significantly higher than that in males. (3) PVEP amplitude was positively correlated with VA， especially with the 64*64 pattern (amplitude criterion indicated VA lower than 0.3: male， 3.85 or lower; female， 3.95 or lower) and a formulas could be established through linear regression analysis. In addition， (4) elevated refractive error showed slower latency， and (5) the 64*64 PVEP amplitude and the second FVEP amplitude demonstrated the highest reliability. Stage two: The VA of students with CI could be estimated through the formula acquired in experiment one. The results， however， must be examined together with clinical assessment from health practitioners or trained school faculty members. Further， in order to facilitate the examination and avoid behavioral disturbances， CI students should be accompanied by their parents， caregivers， or school nurses during examination. Conclusions: The findings can be utilized for the assessment of the VA in students with CI. The examination process itself is， however， not without limitations. A streamlined operation will require the cooperation between the examiner， school teachers/nurses， and parents.