Using a head camera to measure room search performance before and after training in occupational therapy

Background People with visual field deficits and poor spatial attention after stroke often receive search training as part of Occupational Therapy. However, satisfactory methods for measuring search performance in the real world are lacking. This study tested the feasibility of using a head-mounted camera to measure search in the home environment. Methods: Nine participants with visual field deficits post-stroke carried out a search task in their living rooms, before and after a three-week Occupational Therapy search training intervention. For the assessment 16 searches were performed from a central seated position. A small object was placed pseudo randomly in each of eight sectors of the room. The frequency of looking ‘camera fixations’ between the two halves of the room; initial side of the room for starting the searches and search times before and after training were measured. Results: Before training, 3/9 participants had an asymmetry in frequency of looking to the blind side: 35%, 30%, 44%. After training, their searching of the two halves of the room was equally distributed (50%, 51%, 53%). 5/9 participants, started their searches on the affected side more frequently after training, but this resulted in increased search times, for four of them, when the object was on their unaffected side (14s,36s,7s,17s). Two participants had shorter search times when the object was on the blind side (-111s, -11s). Conclusions: This investigation demonstrates the use of a head-mounted camera to measure search behaviour in the home environment and shows changes in performance in wide-field naturalistic search after intervention.