---
title: "EMPATH trial: Mobile, gamified prism adaptation (Peg-the-Mole) for post-stroke spatial neglect"
id: "plos-one-19-empath-protocol-randomized-double-blind-trial-of-an-engaging-and-mobile-prism"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-19-empath-protocol-randomized-double-blind-trial-of-an-engaging-and-mobile-prism"
content_type: "clinical_feed_article"
specialty: "Neurology"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0356055"
published_at: "2026-08-17T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# EMPATH trial: Mobile, gamified prism adaptation (Peg-the-Mole) for post-stroke spatial neglect
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-one-19-empath-protocol-randomized-double-blind-trial-of-an-engaging-and-mobile-prism
- **Specialty:** [Neurology](https://medichelpline.com/clinical-feed/neurology.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0356055)
- **Published At:** 2026-08-17T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- Spatial neglect is a common post-stroke attentional disorder that impairs detection and response to stimuli on the contralesional side and affects 30–50% of stroke patients, causing reduced independence, impaired ADLs, longer hospital stays, and increased caregiver burden. - Many interventions lack standardization and are resource-intensive; anosognosia (lack of awareness) occurs in up to 64% of patients and can reduce treatment adherence, favoring bottom-up approaches. - **Prism adaptation (PA)** is a bottom-up rehabilitation technique that shifts the visual field with **prism goggles**, induces pointing errors, and after repeated reaching produces therapeutic **after-effects** (leftward shift) that can reduce neglect symptoms and improve function. - Therapeutic effects are more consistently found with prism shifts of at least 10°; smaller shifts (5–6°) or sham controls often show no effect in prior RCTs. - PA advantages include short administration time (10–15 minutes/day for ~10 days) and minimal reliance on patient strategic processing, but conventional PA faces barriers: repetitive tasks, need for occlusion boards or specialized equipment, clinician supervision, and limited accessibility. - The EMPATH protocol tests a gamified, mobile computerized PA procedure called **Peg-the-Mole**, designed for inpatient and community/home settings to improve accessibility and engagement. - Study design: longitudinal, double-blind, quasi-randomized, controlled trial of 42 adults with right-hemisphere stroke and mild to severe neglect, randomized to Peg-the-Mole with 15° rightward-deviating prism goggles (intervention) or 5° rightward-deviating prism goggles (active control). - Intervention schedule: 10 treatment sessions across 2 weeks, 15 minutes daily per session. Blinded assessments pre-treatment, post-treatment, and at one-month follow-up. - Primary outcome: Star Cancellation subtest of the Behavioural Inattention Test. Secondary outcomes: other Behavioural Inattention Test subtests, one Eschenbeck ADL subtest, Halifax Neglect Impact Scale (caregiver and self-report), feasibility and acceptability metrics, prism adaptation after-effects, Hospital Anxiety and Depression Scale, and Fatigue Severity Scale. - Trial registration: ClinicalTrials.gov NCT05595668 (registered October 27, 2022). Group-level data will be available on request; full protocol publicly available. Funding from Nova Scotia Health Research Fund; authors report no competing interests.
## Clinical Analysis & Structured Key Points
EMPATH protocol: Randomized, double-blind trial of an Engaging and Mobile Prism Adaptation Treatment for spatial neglect in Home and rehabilitation settings | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract Background Spatial neglect is a common attentional condition post-stroke linked to poor rehabilitation outcomes. Prism adaptation, though a promising intervention, is not yet widely used clinically due to various barriers to its implementation, including limited accessibility, the repetitive nature of the therapy, and the need for specialized equipment. This protocol aims to examine the effectiveness, feasibility, and acceptability of an engaging, mobile, computerized prism adaptation procedure (Peg-the-Mole) for treating spatial neglect in stroke inpatient and outpatient community settings. Methods/design The present study uses a longitudinal, double-blind, quasi-randomized, controlled design. Forty-two individuals with right-hemisphere stroke experiencing mild to severe symptoms of neglect will be randomized into two groups: Use of Peg-the-Mole with 15-degree rightward-deviating prism goggles (intervention) or use of Peg-the-Mole with 5-degree rightward-deviating prism goggles (active control). Participants will complete 10 treatment sessions over 2 weeks, engaging with the Peg-the-Mole procedure for 15 minutes daily. Blinded assessments will take place immediately before and after treatment, as well as at one-month follow-up. The primary outcome measure will be the Star Cancellation conventional subtest of the Behavioural Inattention Test. Secondary outcomes will include additional conventional and behavioural subtests of the Behavioural Inattention Test, one subtest of the Eschenbeck Standardized Activities of Daily Living battery, the caregiver- and self-reported forms of the Halifax Neglect Impact Scale, data measuring feasibility and acceptability, prism adaptation after-effects, the Hospital Anxiety and Depression Scale, and the Fatigue Severity Scale. Discussion The Peg-the-Mole procedure has the potential to improve patient recovery and quality of life after stroke due to its gamified, portable features that promote treatment accessibility and adherence. Results from this study will help determine if the treatment can be implemented successfully in inpatient and community settings to improve neglect symptoms and daily living. Trial registration Clinicaltrials.gov, Identifier: NCT05595668 ; registered October 27, 2022. Citation: MacPhee C, Eskes G, Mackinnon SP, Champod AS (2026) EMPATH protocol: Randomized, double-blind trial of an Engaging and Mobile Prism Adaptation Treatment for spatial neglect in Home and rehabilitation settings. PLoS One 21(8): e0356055. https://doi.org/10.1371/journal.pone.0356055 Editor: Maheshkumar Baladaniya, Neighborhood Physical Therapy, UNITED STATES OF AMERICA Received: June 30, 2025; Accepted: July 25, 2026; Published: August 17, 2026 Copyright: © 2026 MacPhee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The study protocol will be available for public access. However, given the clinical nature of the dataset collected in the present study, only group-level data will be available upon request. Funding: This work was supported by the Nova Scotia Health Research Fund (grant number 1027848 to ASC and GE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Introduction Spatial neglect is a common and debilitating attentional disorder characterized by an inability to detect, orient to, or respond to stimuli presented on the contralesional side of space [ 1 ]. This condition is not due to primary sensory or motor impairments [ 2 , 3 ]. It affects approximately 30-50% of stroke patients, often leading to impaired daily functioning, loss of independence, and slower recovery [ 4 – 6 ]. Symptoms of neglect can lead to serious functional impairment and interfere with mobility, navigation ability, reading, and self-care activities such as eating, dressing, and grooming [ 4 ]. It is estimated that approximately 40% of individuals with neglect may go on to develop chronic symptoms [ 7 , 8 ]. Given the debilitating impact of spatial neglect on functional independence, individuals often require increased assistance with activities of daily living (ADLs) which in turn may lead to greater caregiver reliance and burnout [ 6 , 9 ]. Loss of independence in everyday life can also reduce quality of life and may contribute to depression, anxiety, and fatigue [ 10 , 11 ]. Moreover, spatial neglect is associated with longer hospital stays and higher re-admission rates, placing additional strain on healthcare systems [ 12 – 14 ]. Taken together, these challenges highlight the need for easily accessible, effective, and standardized rehabilitation interventions that can enhance functional independence, reduce caregiver burden, and alleviate pressure on the healthcare system. Various approaches are available for the treatment of spatial neglect, but there is currently no universally accepted standard of care [ 15 – 17 ]. Many existing interventions are resource-intensive, requiring clinician supervision and specialized equipment, and they often lack standardized guidelines [ 17 – 19 ]. Further complicating treatment, up to 64% of individuals with neglect experience a comorbid syndrome called anosognosia, a lack of awareness of their deficits [ 20 ]. The presence of both spatial neglect and anosognosia can significantly reduce treatment adherence, often leading to poorer rehabilitation and clinical outcomes [ 20 , 21 ]. Treatment methods are generally divided into two categories, bottom-up (i.e., stimulus-driven) and top-down (i.e., goal-driven) approaches. Given the high prevalence of anosognosia in individuals with spatial neglect, a bottom-up approach is often more appropriate, as these individuals may lack the motivation to develop strategies to address a deficit they do not recognize [ 20 ]. Prism adaptation (PA) is a promising bottom-up treatment for spatial neglect. This technique involves wearing prism goggles that shift the visual field rightward, with participants repeatedly pointing towards visual targets. Initially, the visual shift causes rightward pointing errors (i.e., direct effects), but with continued reaching, participants adapt until they can accurately point to the targets again. After 10–15 minutes of prism exposure and reaching, removing the prism goggles results in therapeutic effects called after-effects (i.e., a leftward shift in pointing movements), which may reduce the severity of neglect symptoms and improve daily functioning [ 22 – 25 ]. Thus, PA may have high feasibility as a treatment approach, as it requires little training and does not rely on patient strategy or knowledge of their symptoms [ 18 , 26 ]. Two processes are proposed to underlie the development of after-effects induced by PA as described by Redding and Wallace: strategic recalibration and spatial realignment [ 27 – 30 ]. Strategic recalibration is hypothesized to be an immediate response to pointing errors during PA due to the visual shift, with conscious corrections made to reduce errors in subsequent trials. Conversely, spatial realignment is conceptualized primarily as a slow occurring, unconscious process consisting of the remapping of proprioceptive and visual spatial maps to minimize the discrepancy between the position of the hand and the visual location of the target, leading to the development of after-effects. Strategic recalibration may interfere to some extent with the development of after-effects, although it is thought to still contribute to adaptation during PA [ 27 ]. Thus, strategic recalibration during PA is typically minimized using equipment such as an occlusion board to block the patient’s view of their pointing movements to prevent immediate self-correction. The strength of the prismatic shift is an important factor to consider when evaluating the effectiveness of PA treatment. Randomized controlled trials using sham (i.e., clear) goggles as controls, as well as prisms with smaller shifts (5–6 degrees), found no significant therapeutic effects on conventional and functional outcomes [ 31 , 32 ]. In contrast, studies using prisms inducing a shift of at least 10 degrees have shown promising results, with improvements in both symptom severity and functional outcomes [ 22 , 25 ]. Therefore, a shift of at least 10 degrees is generally recommended to achieve therapeutic effects [ 17 , 32 ]. PA has several advantages as a neglect treatment. It is a bottom-up method requiring minimal strategic processing, making it suitable for individuals with anosognosia, as it does not rely on their awareness of symptoms. PA also has a short administration time, typically requiring 10–15 minutes per day for about ten days [ 33 ]. Previous research has demonstrated that PA is effective in reducing symptoms of neglect, with some improvements extending to ADLs [ 22 – 24 , 34 ]. However, PA has certain limitations that need to be addressed. For example, the repetitive nature of typical PA protocols can reduce patient engagement, and the use of specialized equipment such as an occlusion board, used to block the participant’s view of their hand, is required [ 35 , 36 ]. Clinical supervision in a hospital or research setting is required to ensure the correct procedure is followed, resulting in frequent and repeated travel for each treatment session [ 36 ]. Previous research also has found inconsistent evidence for the efficacy of PA, likely reflecting the absence of a standardized protocol and uncertainty surrounding which patients are most responsive to the intervention [ 17 ]. Chen et al. (2025) highlight the substantial methodological heterogeneity across PA studies, including variation in prism strength, treatment intensity, arm visibility during adaptation, outcome measurement, and patient characteristics (e.g., time post-stroke). Furthermore, not all individuals with neglect benefit from PA, and factors such as neglect subtypes (e.g., perceptual vs. premotor neglect) and time since stroke onset may impact its effectiveness [ 26 , 37 ]. Thus, clinical recommendations of PA remain tentative due to methodological limitations of previous research and inconsistent outcomes [ 17 , 38 ]. Therefore, although PA may be a feasible treatment for spatial neglect at present, its implementation has been limited to date. The current gaps interfering with the clinical implementation of PA underscore the need for standardized, evidence-based protocols that increase accessibility and engagement, thereby improving long-term functional outcomes in individuals with spatial neglect. To address these barriers to the clinical application of PA procedures, a home-friendly, game-like PA software called Peg-the-Mole (PTM) was developed. In this protocol, participants wear prism goggles and are prompted to touch as quickly as possible a target bull’s eye held by a cartoon mole presented on an iPad. In comparison to typical PA procedures, PTM requires minimal supervision because the software provides automated instructions, feedback, and data recording, allowing participants to complete sessions independently once trained. The program’s game-like interface enhances engagement and motivation. Importantly, PTM incorporates an adaptive algorithm that adjusts target presentation time based on individual performance, encouraging rapid, ballistic movements and minimizing conscious self-correction during pointing. This algorithm promotes the spatial realignment processes underlying PA while reducing the need for specialized equipment (e.g., occlusion boards). Taken together, these features increase accessibility by enabling standardized, engaging delivery of PA in various settings [ 36 ]. Initial testing of PTM was conducted in a sample of healthy young adults comparing it to a typical PA procedure using 15-degree rightward-deviating goggles [ 36 ]. Results indicated that prism exposure during PTM yielded adaptation and significant after-effects of equivalent magnitude to those observed with a typical PA procedure. Importantly, participants found PTM to be more enjoyable and engaging than the typical PA procedure. Further PTM studies with both healthy young and older adult samples demonstrated that 15-degree prism goggles induced significantly larger after-effects than 5-degree goggles [ 39 ]. Additionally, after-effects induced by PTM have generalized to aspects of wheelchair maneuvering (e.g., a significant reduction in the number of right-sided hits), providing evidence that PTM has the potential to generalize to more functional tasks [ 40 ]. More recently, a pilot study examined the feasibility of implementing a desktop version of PTM with stroke patients in an inpatient rehabilitation unit. PTM was administered daily for 10 sessions over two weeks by occupational therapists and the protocol was generally found to be feasible and engaging [ 41 ]. In the present study, we adapted PTM for iPad administration to enhance flexibility and accessibility for at-home use. To support the future clinical implementation of PTM, the primary objective of the present study is to examine PTM’s effectiveness in reducing neglect symptoms as measured by the Star Cancellation task of the Behavioural Inattention Test (BIT) [ 42 ]. Short-and longer-term effectiveness will be examined in terms of symptom reduction (i.e., does the PTM PA protocol improve neglect symptoms over time?). We hypothesize that participants who complete 10 sessions of PTM PA treatment using 15-degree rightward-deviating goggles will show a greater reduction in the severity of neglect symptoms immediately after training and at one-month follow up, compared to participants using the PTM protocol with 5-degree deviating goggles. Secondary objectives include (1) examining treatment effects across additional neglect measures, as well as measures of ADLs, (2) evaluating feasibility and acceptability, (3) examining the magnitude of PA after-effects and the relationship between these effects and neglect severity, and (4) exploring changes in psychological outcomes. First, we will examine whether the 15-degree PTM condition leads to broader improvements in neglect symptom severity across additional neglect assessments, as well as improvements in ADL functioning over time. Second, we will evaluate the feasibility and acceptability of using the iPad-based PA treatment in both inpatient and community settings. Feasibility will be assessed based on compliance with the treatment protocol and schedule, while acceptability will be evaluated through patient feedback. PA after-effects (mean difference in degrees of visual angle from pre- to post-PTM) will be measured after each treatment session. We will examine whether the 15-degree condition produces larger after-effects compared to the 5-degree condition. Additionally, we will investigate whether the magnitude of PA after-effects predicts neglect severity. The relationships between neglect severity and psychological variables, including anxiety, depression, and fatigue, as well as changes in these psychological outcomes following participation in the PTM protocol will also be explored. Although fatigue, anxiety, and depression are prevalent post-stroke [ 43 , 44 ], their association with spatial neglect remains underexplored, and these secondary analyses will provide insight into the broader impact of PTM and whether improvements in neglect symptoms may be associated with changes in psychological outcomes and fatigue severity. Materials and methods Study design and setting The current study uses a longitudinal, quasi-randomized, double-blind, controlled design to compare the effects of using the PTM protocol with 15-degree versus 5-degree prism goggles, each provided in addition to usual care. The study is registered at Clinicaltrials.gov (NCT05595668) and follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines [ 45 ]. The present study has received ethics approval from the Nova Scotia Health Research Ethics Board (REB File #:1028679; dated March 6 th , 2023). All participants will provide written informed consent prior to participation. Participants will be initially screened for inclusion and exclusion criteria before undergoing a baseline assessment (see criteria below). Participants currently experiencing symptoms of spatial neglect, as determined by the baseline assessment, will be randomized, stratified by neglect severity, to one of two groups: experimental condition (PTM with 15-degree rightward-deviating goggles) or active control condition (PTM with 5-degree rightward-deviating goggles). Each participant will be assigned an “Assessor”, responsible for all assessments, and a “Trainer”, responsible for overseeing the PTM protocol training and scheduling. Trainers will observe participants during the first PTM session to ensure proper adherence to the protocol. Participants will then complete 10 daily training sessions over two weeks (5 days per week), with each session lasting approximately 15 minutes. Assessments will be conducted at 3 time points: baseline (T0), within one week after the final treatment session (T1; immediate follow-up), and within 4–6 weeks after the final treatment session (T2; one-month follow-up). After each PTM training session, after-effects will be measured, and the treatment and after-effects data will be stored on the iPad for later download. At T1, participants will independently set up and complete training in front of their Assessor to confirm their ability to follow the protocol as trained. The study will be conducted both in the community and across various hospital sites in Nova Scotia, Canada. Data collection is currently ongoing. This trial is open to recruitment from June 20 th , 2024, to August 31 st , 2027. Data collection is anticipated to be complete by September 2027, and results are anticipated by August 2028. See Fig 1 and Fig 2 for the study schedule and timeline, respectively. Download: PNG larger image TIFF original image Fig 1. EMPATH study schedule (SPIRIT guidelines). https://doi.org/10.1371/journal.pone.0356055.g001 Download: PNG larger image TIFF original image Fig 2. Study timeline. After the baseline assessment (T0), eligible participants are randomized (stratified by neglect severity) and undergo a 10-day treatment over two weeks. Follow-up assessments occur within one week and one month of finishing treatment (T1, T2, respectively). https://doi.org/10.1371/journal.pone.0356055.g002 Study population Participants with right-hemisphere stroke will be recruited from several sites in Nova Scotia: the Acquired Brain Injury Program at the Nova Scotia Rehabilitation and Arthritis Centre, the Early Supported Stroke Discharge Team, and the Acute Stroke Program of the Valley Regional Hospital. Recruitment is also open to the community. Participants may be referred to the study by a clinician or directly recruited from the community by the research team through advertisement and stroke support group visits. Study staff will visit participants for training and assessments, either at their home or in inpatient units, depending on each participant’s current admission status. For participants who enroll while in an inpatient unit but are discharged before completing the study, a hybrid approach will
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