ABSTRACT
There is a need for objective, easy and relatively short methods to diagnose cognition in depression. We have constructed a set of simple visual tasks using three different ways of speed measuring: paper-pencil-based, computer-based, and eye-tracking based. We used a single case design with 22 participants. A clinical group counted 11 patients with major depression examined two times (first examination without medication and second after three months of medical treatment) together with a group of 11 matched healthy controls. Cognitive difficulties were observable in all the checked levels of performance. The weakest in all tasks were patients before medication, some improvement was observed after medical treatment, but not matching the level of healthy controls. Cognitive difficulties were not eliminated by medical treatment as quickly as emotional disturbances were. The observed difficulties could be interpreted in terms of psychomotor retardation, a typical symptom in depression, which proved to be mainly cognitive as the analysis of differences in reaction times and the first saccade latencies concluded. The analysis of simple visual reaction times on several stages turned out to be a promising method to measure the cognitive state in persons with mood disorders and cognitive convalescence during major depressive disorder treatment.
ABSTRACT
BACKGROUND: Major depression (MD) is the one of the most debilitating diseases, affecting millions of people all around the world. OBJECTIVES: To establish visual pathway function in untreated individuals with MD. MATERIAL AND METHODS: In 29 untreated, newly diagnosed, ophthalmologically asymptomatic individuals (58 eyes) with MD (mean age: 47.3 years) and in 29 (58 eyes) of age-, sexand refractive error-matched healthy controls (mean age: 46.8 years), the following examinations were performed: 1) best corrected distance visual acuity (BCDVA); 2) intraocular pressure (IOP); 3) and 4) biomicroscopy of anterior and posterior segment of eye; 5) macular structure (SD-OCT-Zeiss); and 6) pattern visual evoked potentials (PVEPs) measurements according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standard (ISCEV-standard PVEPs). An analysis of correlation between the parameters of PVEPs and the depression severity (Hamilton Depression Rating Scale (HAMD)) was performed. To estimate the diagnostic power of PVEPs test, a receiver operating characteristics (ROC) curve was used. Data were analyzed with the significance level of p < 0.05. RESULTS: In the study group and in healthy control, the clinical results and macular structure were normal and not different. In the MD group, in PVEPs test (check size: 1°4'and 0°16'), a significant decrease of amplitudes of P100 (AP100), associated with prolonged P100 peak time (PTP100; check size: 0°16', p < 0.004) were detected. The most frequent abnormality in PVEPs examination in the MD group was AP100 reduction (in 69% of individuals) detected using stimulation check size 0°16'. The statistically significant positive correlation between PTP100 (check size: 0°16') and HAMD score was found in severe MD (p = 0.03). The analysis of ROC curve revealed the highest sensitivity of 0.759 and specificity of 1.0 for AP100 (0°16'). The area under the curve (AUC) was 0.841 (p < 0.001). CONCLUSION: In individuals with newly diagnosed, ophthalmologically asymptomatic and untreated MD, a dysfunction of visual pathway is present without other signs of ocular pathology. The visual pathway dysfunction measured with ISCEV PVEPs has a potential value to be an objective biomarker of MD.
