Jan Johansson, Kristina Franzon, Alison K. Godbolt, Marika C. Möller
Department of Clinical Neuroscience, Eye and Vision, Marianne Bernadotte Centre, Karolinska Institute, St Erik Eye Hospital, Stockholm, Sweden. E-mail: jan.johansson.1@ki.se
DOI: 10.2340/16501977-2847

Objective: To evaluate the feasibility of using a wearable eye-tracker when assessing patients with prolonged disorders of consciousness using the Coma Recovery Scale Revised (CRS-R), focusing on technical challenges.
Design: A methodological investigation with descriptive and analytical elements.
Subjects: Four patients with prolonged disorders of consciousness were recruited from the rehabilitation 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 observed, suggesting likely patient acceptability. Calibration 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 detection 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.

Some survivors of profound acquired brain injury develop a prolonged disorder of consciousness. Differentiation of the stage of prolonged disorders of consciousness is of relevance when planning rehabilitation and informing families. It currently relies largely on clinical assessment using standardized neurobehavioural rating scales. In the Coma Recovery Scale Revised (CRS-R) the patient is encouraged to perform tasks while the clinician observes. The patient’s responses may, however, be difficult to interpret due to impairments associated with the brain injury. The objective of this study was to develop eye-tracking as a supporting tool to CRS-R assessment of patients with prolonged disorders of consciousness. A selection of subtests in the CRS-R were performed while recording eye movements with a wearable eye-tracker. No major adverse reactions were observed, suggesting likely patient acceptability. Distinct eye movements were discernible from the recorded data, and analysis of these gave results with the potential to support clinical assessment. Further study is merited.