A portable eye tracking experiment for the assessment of cognitive impairment in presymptomatic frontotemporal dementia

Abstract

AbstractBackgroundEye tracking can be useful for measuring cognitive function in frontotemporal dementia (FTD), as the tasks do not require behavioural or verbal responses. However, most systems are highly expensive and require experiments to be conducted in artificial environments. We developed a fully portable eye tracking protocol using the Tobii Pro Nano, a small, low‐cost eye tracker. The aim was to investigate if the portable experiment can detect presymptomatic impairment in FTD using instructionless tasks of social cognition.MethodParticipants were recruited from the Genetic FTD Initiative (GENFI), including 41 mutation carriers (mean age = 43.0, standard deviation (SD) = 11.0), and 14 non‐carriers (mean age = 40.4, SD = 7.14). Participants completed tasks of simple and complex emotion recognition that involved viewing four images (one target face (simple) or pair of eyes (complex) and three non‐target) followed by a target emotion word and then the original four images alongside the emotion word. A dwell time change score was calculated by subtracting the percentage dwell time for the target image before the word appeared from the percentage dwell time after the word appeared. A lower dwell time change score signifies impaired performance. Linear mixed effects models were used to compare performance on each of the tests, with the dwell time change score included as the variable of interest and age, target type (target, non‐target), and genetic status (carrier, non‐carrier) included in the model as fixed effects.ResultThe average (standard deviation) mean percentage dwell time change score in the target image was lower at 52.2% (15.8) for the mutation carriers compared with 56.5% (7.01) for non‐carriers on the simple emotion task (p = 0.006), and 23.4% (11.2) for carriers compared with 27.3% (7.46) for non‐carriers on the complex emotion task (p = 0.076).ConclusionThese eye tracking tasks may be a useful tool for assessing deficits in social cognition in presymptomatic FTD, something that has been difficult to measure with pen and paper neuropsychometry. Therefore, this portable eye tracking experiment has the potential to be a low‐cost biomarker for monitoring the progression of FTD in clinical trials, both at home and in the clinic.