Reading difficulties in people with homonymous hemianopia: a systematic review of all reported interventions

Reading difficulties are among the most commonly reported problems in people with homonymous visual field defects (HVFDs). The nature and severity of reading problems can vary from person to person and are not exclusively related to the side and size of the field defect. We conducted a systematic review to provide an overview of all possible HVFD interventions with a potential effect on reading, with the aim of providing guidance for healthcare professionals who are considering offering reading training or other intervention to someone with HVFD.

A total of 57 publications were included in our review: 22 pre-post studies, 10 RCTs, 8 case report (series), 7 case-control studies, 4 controlled trials, 2 observational studies, 1 cross-over study, 1 prospective non-controlled trial and 1 prospective cohort study. We performed quality assessment of each publication, and categorised the interventions based on the type of intervention, number of sessions, duration of sessions, intervention intensity, total duration of the intervention and the conditions under which the intervention was offered (home or outpatient). Furthermore, we mapped the different outcome measures, such as reading speed, number and type of errors and reading comprehension.

In total, 66 interventions were identified, of which 20 primarily aimed at improving reading performance, while 43 constituted general HVFD interventions. Overall, compensatory saccadic adaptation interventions were most frequently reported. A wide variety of reading-related outcome measures were used, of which 81 performance measures and 29 measures of self-report instruments.

Our review can support professionals and their clients in choosing the intervention that best fits the nature and severity of the reading problem and potentially gives the best chance of improvement. There is a need for more basic research into the underlying mechanisms of reading problems in HVFDs and how interventions relate to them. In addition, more validated outcome measures that are able to determine improvement at activity and participation levels are desirable.