Methodological aspects of using a wearable eye-tracker to support diagnostic clinical evaluation of prolonged disorders of consciousness

Objective: To evaluate the feasibility of using a wear- able eye -tracker when assessing patients with pro- longed disorders of consciousness using the Coma Recovery Scale Revised (CRS -R), focusing on tech- nical challenges. Design: A methodological investigation with descrip- tive and analytical elements. Subjects: Four patients with prolonged disorders of consciousness were recruited from the rehabilita- tion clinic of a regional rehabilitation unit. Methods: A selection of subtests in the CRS -R were performed while recording eye movements with a wearable eye -tracker. Results: No major adverse reactions were observ- ed, suggesting likely patient acceptability. Calibra- tion was not always possible. However, distinct eye movements were discernible from the recorded data even without calibration, and analysis of these produced results with the potential to support clinical assessment. Conclusion: Eye tracking was feasible during clinical assessment for this patient group. Recording eye movement responses in these easily fatigued patients has the potential to add sensitivity for de- tection of conscious responses and to complement clinical examination. Further study is merited. Current hardware and software limitations can be overcome with manual data processing and analysis; however, significant developments in automating data processing will be required for broader clinical application.