Portable eyetracking-based assessment of memory decline

Introduction: Preferential viewing of novel stimuli in the Visual Paired Comparison task has provided a useful marker of memory and medial temporal lobe function. We created a portable version of the VPC (P-VPC) and contrasted P-VPC metrics against the Montreal Cognitive Assessment (MoCA) in healthy adults, to assess the validity and reliability of the P-VPC as an indicator of memory function across age. A supplementary case series was conducted with individuals diagnosed with Alzheimer's disease (AD) and other dementias, to provide a preliminary illustration of the P-VPC's use as a measure in clinical populations.

Method: Participants (n = 207) were tested using the P-VPC. Individuals were familiarized with a set of objects, which were each presented alongside a novel object in the test phase. Novelty viewing scores were compared to MoCA scores to index concurrent validity. Item analyses were conducted as a test of internal reliability of the P-VPC. A complementary clinical case series was conducted with AD (n = 4) and dementia (n = 5) participants, who were tested using the P-VPC and further compared to healthy age-matched participants.

Results: Preferential viewing decreased with age in healthy participants, and was positively correlated with MoCA scores. Compared to the MoCA, P-VPC scores did not differ based on education and/or whether English was spoken as the native language. Item analyses revealed acceptable internal consistency. P-VPC viewing percentiles of healthy participants were modeled as a function of age, and illustrated that individuals of the clinical case series diagnosed with AD scored in below-average percentiles, while those with dementia did not score below-average.

Conclusion: Good concurrent validity and acceptable internal reliability were observed, and P-VPC scores were not confounded by education or language experience. Low performance was observed in individuals with clinically diagnosed AD, suggesting that the P-VPC may be a potential tool for screening memory decline.