[ARTICLE] The clinical effectiveness of Eye-Search therapy for patients with hemianopia, neglect or hemianopia and neglect

ABSTRACT

We investigated the clinical effectiveness of Eye-Search, a web-based therapy app designed to improve visual search times, in a large group of patients with either hemianopia, neglect or both hemianopia and neglect. A prospective, interventional cohort design was used. For the main, impairment-based outcome measure (average visual search time), the within-subject control was affected vs. unaffected side. Four hundred and twenty-six participants who fitted the inclusion criteria completed all 4 time points (1200 therapy trials). We found a significant three-way interaction between therapy, side and group. Eye-Search therapy improved search times to the affected visual field of patients with either hemianopia alone or neglect and hemianopia, but not those with neglect alone. Effect sizes were moderate to large and consistent with previous studies. We found a similar significant interaction between therapy and group for the patient-reported outcome measure “finding things” that most closely matched the impairment-based outcome (visual search). Eye-Search therapy improves both impairment-based and patient-reported outcome measures related to visual search in patients with hemianopia alone or hemianopia and neglect.

Introduction

Hemianopia and neglect are the two most common visual disorders complicating posterior brain injury (Corbetta et al., 2005; Rowe et al., 2019). While neglect is more likely to spontaneously improve over the first year post-injury than hemianopia, both have long-term effects on patients’ activities of daily living (Warren, 2009; Wee & Hopman, 2008). Several behavioural approaches to treating patients with persistent hemianopia have been successfully trialled. The most consistently effective therapies promote retraining of compensatory eye movements, by practising voluntary guided saccades (e.g., patients have to find a visual target amongst distractors, or find a target that has “jumped” to a new location in their blind field (Jacquin-Courtois et al., 2013; Schuett et al., 2012)). Eye-movement therapies have also been shown to be effective in treating the symptoms of neglect, although these rely on stimuli that induce smooth-pursuit eye movements (e.g., patients have to focus on targets that move towards their neglected side at a constant velocity (Hopfner et al., 2015; Kerkhoff et al., 2014)). We have previously reported on the clinical efficiency of Eye-Search (https://www.eyesearch.ucl.ac.uk/), a web-based therapy that improves visual search in patients with hemianopia, but in that study (n = 78) we left out patients with neglect (Ong et al., 2015). As hemianopia and neglect can co-occur (Muller-Oehring et al., 2003), the aim of this study was to investigate whether Eye-Search therapy works in patients with either neglect alone (“pure neglect” group) or hemianopia and neglect. We also extended the criteria for length of participation in the study from three time points (patients completed 800 therapy trials), to four (1200 therapy trials completed).

Materials and methods

Setting

All subjects’ data were collected using the Eye-Search browser-based app. This study was approved by the UCL Research Ethics Committee: 2681/001, and all participants consented to the use of their data. All data were anonymized and held securely on a UCL server. The Eye-Search app has five main data collecting components:

1. A test to identify hemianopia

2. A test to identify visual neglect

3. The therapy: a ramp-step paradigm, embedded in a game, that delivers the trial-by-trial eye-movement practice

4. An impairment-based outcome measure: a visual search task

5. A patient-reported outcome measure (PROM): a visual analogue scale for rating difficulty performing six activities of daily life

Subjects re-tested themselves on the two visual tests and two outcome measures before they started therapy (baseline) and then every time that they completed a block of 400 trials (T1 = after 400 trials, T2 after 800 and T3 after 1200).

Study population and selection criteria

The therapy took place at the discretion of the patient and on their personal computers. Due to the nature and delivery modality of the therapy, the patients are considered to be self-enrolled, rather than traditionally recruited. The data analysed in this study were collected from participants who used the Eye-Search website between July 2012 and February 2019. In this period, 1407 participants took part, out of which 426 fitted the inclusion criteria (see consort diagram Figure 1). Of these, 302 (71%) were male. The mean participant age was 60 years [SD 14.6]. Causative diagnosis was self-reported with 6% leaving the section blank. The remaining patients were divided as follows: 84% stroke; 5% head injury; 3% surgery; and, 2% reported other causes such as an abscess, CO poisoning and encephalitis. Time between the cause of their visual impairment and starting therapy was positively skewed, median 85 days [IQR = 44–210 days]. Progress through the therapy was self-paced. The time to get from baseline to T1 and T3 was also positively skewed with subjects taking a median time of 5 days [IQR = 2–12 days] and 20 days [IQR = 9–33 days], respectively.

Figure 1. Consort diagram showing the identification of participants in the study.

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