Abstract
Subjective testing of horizontal saccades has been used for screening mild traumatic brain injury (mTBI) and neurodegeneration. However, vertical saccades, having longer latencies for aged compared to younger subjects, may be more sensitive for detecting brain disturbance. To explore whether subjective assessment of vertical saccades can be used as an early indicator of brain pathology, a test involving vertical saccades that avoids predictable eye movements must be developed and data collected on healthy subjects for comparison. Subjects were 210 healthy, young adult optometry students without mTBI within 3 months of testing or current medications that affect eye movements, divided into 2 groups (CL2023, N = 129 and CL2024, N = 81). Data collection for the 2 groups was 1 year apart. Using a novel subjective vertical number naming test (3 subtests), each subject obtained data from 2 other subjects in a well-lit room, recording time to completion (TTC). Rest between blocks of tests was 2-5 minutes. Two-way random intraclass correlation coefficients (ICC) were used to assess repeatability. TTCs were compared between classes using independent samples t-test. Mean TCCs did not differ between groups for any subtest in either block (P > .05). Significantly longer mean TTCs were found for block 1 vs block 2 for all 3 subtests (P < .001). ICCs (95% CI) for average measures for the 2 blocks were .85 (.71, .91)-subtest 1, .89 (.84, .92)-subtest 2, and .92 (.88, .94)-subtest 3. ICCs for vertical number naming show excellent short-term repeatability in this sample, indicating little influence of examiner on the data. A clinically insignificant learning effect may explain the shorter TTCs for block 2. Similarity of data across groups establishes normal ranges for this test in young, healthy adults. Investigation of the utility of subjective assessment of vertical saccades in recent mTBI is warranted.