Compensatory strategies following visual search training in patients with homonymous hemianopia: an eye movement study

Abstract

A total of 29 patients with homonymous visual field defects without neglect practised visual search in 20 daily sessions, over a period of 4 weeks. Patients searched for a single randomly positioned target amongst distractors displayed for 3 s. After training patients demonstrated significantly shorter reaction times for search stimuli (Pambakian et al. in J Neurol Neurosurg Psychiatry 75:1443–1448, 2004). In this study, patients achieved improved search efficiency after training by altering their oculomotor behaviour in the following ways: (1) patients directed a higher proportion of fixations into the hemispace containing the target, (2) patients were quicker to saccade into the hemifield containing the target if the initial saccade had been made into the opposite hemifield, (3) patients made fewer transitions from one hemifield to another before locating the target, (4) patients made a larger initial saccade, although the direction of the initial saccade did not change as a result of training, (5) patients acquired a larger visual lobe in their blind hemifield after training. Patients also required fewer saccades to locate the target after training reflecting improved search efficiency. All these changes were confined to the training period and maintained at follow-up. Taken together these results suggest that visual training facilitates the development of specific compensatory eye movement strategies in patients with homonymous visual field defects.

Efficacy and Feasibility of Home-Based Training for Individuals With Homonymous Visual Field Defects

“…Our study confirmed previous findings on the effectiveness of supervised compensatory training [16][17][18][19][20][21][22][23][24][25][26] , and is the first to demonstrate that reading and exploration skills can be improved following unsupervised training. This finding is of obvious practical relevance, but also of theoretical interest.…”

“…Even the majority of computer-based training is either completed in clinic 16,17 or at home with therapist supervision 20,22,23 , although one recent study has demonstrated that a web-based reading training can increase reading speed in patients with right-sided HVFDs 27 . Whether it is the patient regards to exploration and reading 22,28 .…”

Inefficient search strategies in simulated hemianopia.

“…There are diverse treatment protocols designed to increase scanning of the blind field in hemianopia (e.g.,; Bolognini, Rasi, Coccia, & Ladavas, 2005;Zihl, 1995), and there is evidence to suggest that those treatments increase allocation of attentional resources towards the blind hemifield (Kerkhoff, Munssinger, & Meier, 1994). However, the strategy of making large saccade into the area associated with field deficit advocated in the literature (Mannan et al, 2010;Pambakian et al, 2004;Zihl, 1981) failed to produce significantly better outcomes than the one spontaneously adopted by our observers. A more effective approach may be to train patients to rapidly adjust their search strategy to the particular visual context.…”

Adaptation to poststroke visual field loss: A systematic review

“…The majority of studies relating to compensatory treatments are concerned with the improvement of eye movements and scanning into the affected field (Bergsma et al., 2011; Roth et al., 2009; Aimola et al., 2014; Hazelton, Pollock, Walsh, & Brady, 2015; Jacquin‐Courtois, Bays, Salemme, Leff, & Husain, 2013; Lane, Smith, Ellison, & Schenk, 2010; Pambakian, Mannan, Hodgson, & Kennard, 2004; Kerkhoff, Münssinger, & Meier, 1994; Mazer et al., 2003; Nelles et al., 2010; Taylor, Poland, Harrison, & Stephenson, 2011; Schuett, Heywood, Kentridge, Dauner, & Zihl, 2012), as well as increased saccadic movements into the affected field (Mannan, Pambakian, & Kennard, 2010; Lévy‐Bencheton et al., 2016; Kerkhoff, Münßinger, Eberle‐strauss, & Stögerer, 1992). A number of studies have specifically reported on subjective improvements in activities of daily living following compensatory therapy, such as improvements in mobility, reading, driving, and detection of obstacles (Bergsma et al., 2011; Ong et al., 2015; Keller & Lefin‐Rank, 2010; Aimola et al., 2014; Jacquin‐Courtois et al., 2013; Kerkhoff et al., 1994; Mazer et al., 2003; de Haan, Melis‐Dankers, Brouwer, Tucha, & Heutink, 2015; Hayes, Chen, Clarke, & Thompson, 2012; Nelles et al., 2001; Rowe, Conroy, et al., 2016).…”