Prism adaptation and spatial neglect: the need for dose-finding studies

Short-term effect of prism adaptation treatment on severity of unilateral spatial neglect following right hemispheric stroke: a systematic review and meta-analysis

OBJECTIVE

This work aimed to investigate the effects of prism adaptation on unilateral spatial neglect following right hemispheric stroke.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

PATIENTS

Patients with unilateral spatial neglect following right hemispheric stroke.

METHODS

RCTs comparing prism adaptation with placebo therapy were systematically searched across 4 databases (PubMed, Web of Science, CINAHL, and Cochrane Library). Screening, data extraction, and quality assessment were performed by 2 independent reviewers.

RESULTS

A total of 7 RCTs, involving 227 participants, satisfied the eligibility criteria. The results showed significant short-term effects of prism adaptation on neglect outcomes (SMD: 0.49 [95% CI: 0.07 to 0.92], p = 0.02) but not on the Catherine Bergego Scale (CBS) (SMD: -0.38 [95% CI: -1.27 to 0.51], p = 0.40). Subgroup analyses revealed that larger prism angles (exceeding 10°) had greater prism adaptation effects on both neglect outcomes and CBS (SMD: 0.71 [95% CI: 0.30 to 1.12], p = 0.0007 and SMD: -0.77 [95% CI: -1.51 to -0.02], p = 0.04, respectively).

CONCLUSION

This study demonstrated that larger prism angle with greater than 10° was identified as a crucial factor in eliciting prism adaptation effects. These findings support the use of prism adaptation with angles exceeding 10° as a therapeutic approach for unilateral spatial neglect.

Does prism adaptation treatment reduce spatial neglect and improve function?

The potential of using prism adaptation for treating spatial neglect (SN) was questioned when recent meta-analyses found inconsistent evidence. However, analyses of clinical datasets support the use of prism adaptation treatment (PAT) in reducing SN and improving function. The main objective of this review is to evaluate the current state of the evidence of PAT therapeutic effects, identify knowledge gaps, and make suggestions to guide further research and support clinical decision-making. We used the framework of the National Institutes of Health (NIH) Stage Model for Behavioral Intervention Development which provides guidance on best practices for developing effective behavioral interventions that can be implemented in real-world settings. This model emphasizes the interplay between mechanisms underlying therapeutic effects ("who" should receive the treatment and "how" best does it work?) and considerations of adaptability and feasibility in real-world settings. The present critical review led to the following conclusion: the use of the NIH Stage Model reveals the heterogeneity of PAT studies and challenges in advancing PAT as an effective intervention. The key mechanisms such as prism strength, treatment intensity, arm visibility and activities during treatment, and evaluation methods lack consensus. Therefore, clinical research teams must continue to collect evidence to determine critical mechanisms and the optimal protocol. Further research identifying the optimal PAT protocol is needed before another meta-analysis on PAT's clinical efficacy should be conducted again.

The Rehabilitation for Visual Cognitive Impairment due to Hippocampal Infarction: A Case Report

Introduction

Disturbances in the visual pathway cause visual cognitive impairment. There is a lack of information regarding the effect of rehabilitation on individuals affected by this condition. Therefore, it is crucial to understand the effectiveness of rehabilitation interventions in this condition.

Case Presentation

We present the case of an 87-year-old woman with hippocampal infarction. While the patient's ability to perform daily activities and engage in conversations was normal, she faced challenges at the execution stage, such as naming, constructing sentences, and copying. We diagnosed cerebral embolism because of atrial fibrillation and initiated direct oral anticoagulant therapy. Subsequently, we initiated a rehabilitation treatment comprising visual agnosia training (attribute learning training), verbalization learning training (writing training), and semantic memory training (copying training) to address visual agnosia.

Conclusion

Associative visual perception challenges arising from hippocampal infarcts are rare and can be improved with early intervention through a rehabilitation program for visual agnosia.

A study of prisms and therapy in attention loss after stroke (SPATIAL): A feasibility randomised controlled trial

OBJECTIVE

Investigate feasibility and acceptability of prism adaptation training for people with inattention (spatial neglect), early after stroke, during usual care.

DESIGN

Phase II feasibility randomised controlled trial with 3:1 stratified allocation to standard occupational therapy with or without intervention, and nested process evaluation.

SETTING

Ten hospital sites providing in-patient stroke services.

PARTICIPANTS

Screened positive for inattention more than one-week post-stroke; informal carers. Occupational therapists participated in qualitative interviews.

INTERVENTION

Adjunctive prism adaptation training at the start of standard occupational therapy sessions for three weeks.

MAIN MEASURES

Feasibility measures included recruitment and retention rates, intervention fidelity and attrition. Outcomes collected at baseline, 3 weeks and 12 weeks tested measures including Nottingham Extended Activities of Daily Living Scale. Acceptability was explored through qualitative interviews and structured questions.

RESULTS

Eighty (31%) patients were eligible, 57 (71%) consented, 54 randomised (40:13, +1 exclusion) and 39 (74%) completed 12-week outcomes. Treatment fidelity was good: participants received median eight intervention sessions (IQR: 5, 12) lasting 4.7 min (IQR: 4.1, 5.0). All six serious adverse events were unrelated. There was no signal that patients allocated to intervention did better than controls. Twenty five of 35 recruited carers provided outcomes with excellent data completeness. Therapists, patients and carers found prism adaptation training acceptable.

CONCLUSIONS

It is feasible and acceptable to conduct a high-quality definitive trial of prism adaptation training within occupational therapy early after stroke in usual care setting, but difficult to justify given no sign of benefit over standard occupational therapy.

CLINICAL TRIAL REGISTRATION

https://www.isrctn.com/ Ref ISRCTN88395268.

Prism adaptation treatment improves spatial neglect after severe traumatic brain injury: A case series

BACKROUND

Spatial neglect (SN) after traumatic brain injury (TBI) is common, hindering rehabilitation progress and functional outcomes. Most research has focused on SN treatment after stroke with few published instances of post-TBI SN treated using prism adaptation treatment (PAT) in inpatient rehabilitation.

OBJECTIVE

This case series characterizes the dose, after-effect, and treatment response of PAT in patients with SN after severe TBI.

METHODS

Six patients exhibiting severe (n = 2), moderate (n = 2), or mild (n = 2) SN after severe TBI received 5 to 10 PAT sessions during their inpatient rehabilitation stay. Functional improvement in SN was measured by the Catherine Bergego Scale (CBS).

RESULTS

Patients presented with a mean initial CBS score of 16.8 (range: 8.8-24.3). Prism after-effect was present after PAT. Following 5-10 sessions, the mean CBS score improved by 11.6 points to 5.2 (range: 7.8-21.8); the change in initial versus final CBS scores was significant (P = 0.031).

CONCLUSION

This study is the first to demonstrate prism after-effect and functional SN improvement in individual patients with TBI. Patients showed a clinically meaningful improvement in mild, moderate, and severe SN following 5 to 10 PAT sessions. Additional studies are needed to assess tolerability, benefit, and optimal PAT dose for SN after TBI.

Visuomotor misalignment induced through immersive virtual reality to improve spatial neglect: a case-series study

One evidence-based treatment for spatial neglect is prism adaptation (PA) treatment. PA after-effects, i.e., the implicit shifts in the arm reaching position toward the neglected side of space after prism removal, are considered fundamental to PA treatment effects. In the present study, the arm reaching position was shifted through a visuomotor misalignment procedure using immersive virtual reality (VR). To examine whether this procedure might have a beneficial impact on spatial neglect, we conducted a multi-baseline experiment in three individuals with chronic left-sided neglect post stroke. Improved spatial neglect was observed in all participants immediately after 5 sessions with two rounds in each. Two participants demonstrated lasting or continuous improvement two weeks later. Participants' pattern of brain lesions did not appear to clearly explain performance differences. The findings suggest that VR-induced visuomotor misalignment may improve spatial neglect immediately after a multi-session treatment course. The optimal number of sessions will be determined by future studies with a larger sample size, which may also elucidate the number of sessions sufficient for sustained improvement in most patients. Further investigations will identify the neural mechanisms underlying VR-induced visuomotor misalignment, which may or may not be identical to PA after-effects.

Prism Adaptation Treatment of Spatial Neglect: Feasibility During Inpatient Rehabilitation and Identification of Patients Most Likely to Benefit

Objective

Spatial Neglect is prevalent among stroke survivors, yet few treatments have evidence supporting efficacy. This study examines the feasibility of Prism Adaptation Treatment (PAT) within an inpatient rehabilitation facility and the degree by which PAT improves symptoms of spatial neglect and functional independence among sub-acute survivors of right hemispheric stroke.

Design

In this retrospective cohort study, 37 right hemispheric stroke patients were identified as having received at least 4 PAT sessions during their inpatient stay. Spatial neglect and functional independence levels of patients in the PAT cohort were compared to a matched active control group comprised of rehabilitation patients receiving alternative therapies to address neglect admitted during the same time period.

Results

Most patients received the full recommended 10 sessions of PAT (average sessions completed = 8.6). A higher percentage of severe neglect patients receiving PAT (69%) displayed clinically significant gains on FIM (≥22 points) compared to those receiving alternative treatments (6%). Patients with mild or moderate neglect in the PAT cohort did not exhibit greater benefit than controls.

Conclusion

Provision of PAT for treatment of spatial neglect in right hemispheric stroke patients was feasible during the inpatient rehabilitation admission. Patients with severe neglect showed the most benefit from PAT.

Clinical Trial Registration

This study was registered as a retrospective observational study on Itab Clinical Trials.gov. NCT04977219.

Two weeks of twice-daily prism adaptation treatment does not improve posture or gait in Parkinson's disease: a double-blind randomized controlled trial

Background

Gait difficulties in Parkinson’s disease have been related to problems shifting the center of gravity forward. We previously showed reduced forward stepping latencies for people with Parkinson’s disease after one session of adaptation to upward visual shifts, which produces downward motor after-effects and potentially shifts the center of gravity forward. Here we tested if repeated prism adaptation improved gait and postural control in Parkinson’s disease through a parallel, double-blind, randomized, sham-controlled trial.

Methods

We recruited participants with idiopathic Parkinson’s disease aged 40–85 and meeting any one of three clinical criteria: (1) Hoehn and Yahr Stage II.5–IV; (2) scoring > 0 on the gait, freezing of gait, and/or postural stability items of the Movement Disorder Society Unified Parkinson’s Disease Rating Scale; or (3) Timed Up and Go > 12 s. Sealed envelope style randomization allocated participants to two weeks of twice-daily prism adaptation or sham treatment. Participants, care givers, and those assessing the outcomes were blinded to group assignment. Primary outcomes were changes in postural control measured using the Berg Balance Scale and the Limits of Stability, Sensory Organization, and Motor Control tests from the Smart EquiTest system. Secondary outcomes included other physiotherapy and questionnaire measures. Outcomes were assessed at the Dartmouth Hitchcock Medical Center immediately before and after the treatment period, with further long-term postal follow-up over 3 months. Outcomes were analyzed using analyses of variance with follow-up t tests.

Results

Eighteen participants were allocated to undergo prism adaptation, of which sixteen were analyzed. Thirteen participants were allocated to undergo sham treatment, and all were analyzed. The prism adaptation group showed increased forward stepping velocity on the Limits of Stability test (pre: M=2.33, SEM=0.24; post: M=2.88, SEM=0.26; t(15)=3.2, p=.005, d=.819). The sham group showed no such change (pre: M=2.13, SEM=0.22; 1d post: M=2.24, SEM=0.22; t(13)=.636, p=.537, d=.176). However, there were no group differences for any other outcome measures and no indications that prism adaptation produced functional improvements in posture, gait, or activities of daily living.

Conclusions

Prism adaptation does not improve gait or postural control in Parkinson’s disease.

Trial registration

ClinicalTrials.govNCT02380859. Registered prospectively on 5 March 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05832-2.

The Effects of Continuous vs. Intermittent Prism Adaptation Protocols for Treating Visuospatial Neglect: A Randomized Controlled Trial

Visuospatial neglect may interfere with activities of daily living (ADL). Prism adaptation (PA) is one treatment option and may involve two components: recalibration (more strategic) and realignment (more implicit). We examined whether recalibration or realignment is the driving force in neglect rehabilitation using PA. In a randomized controlled trial with two recruitment series and a cross-over design, 24 neglect patients were allocated to a continuous (PA-c) or intermittent (PA-i) PA procedure. During the PA-c condition, goggles were worn without doffing. In the PA-i condition, patients donned goggles twice (first series of patients) or three times (second series) during training to induce more recalibrations. Primary outcome parameters were performance (omissions) on the Apples Cancellation Test and ADL scores. To assess the efficacy of the PA treatment, we compared effect sizes of the current study with those from three groups from previous studies at the same rehabilitation unit: (1) a passive treatment with a similar intensity, (2) a placebo treatment with a similar intensity, and (3) a PA treatment with fewer therapy sessions. Treatment conditions did not significantly predict scores on primary and most secondary outcome parameters. However, the spontaneous ipsilesional body orientation improved only in patients receiving the PA-i condition and this improvement also appeared in patients showing a strong after-effect (irrespective of condition). Effect sizes for the Apples Cancellation Test and the Functional Independence Measure were larger for both PA treatment protocols than the historical control groups. We conclude that more recalibrations during an intermittent PA treatment may have a beneficial effect on spontaneous body orientation but not on other aspects of neglect or on ADL performance. Clinical Trial Registration: German Clinical Trials Register, identifier: DRKS00018813, DRKS00021539.

Prism Adaptation Treatment Improves Inpatient Rehabilitation Outcome in Individuals With Spatial Neglect: A Retrospective Matched Control Study

Objective

To determine whether prism adaptation treatment (PAT) integrated into the standard of care improves rehabilitation outcome in patients with spatial neglect (SN).

Design

Retrospective matched control study based on information extracted from June 2017-September 2019.

Setting

Inpatient rehabilitation.

Participants

Patients from 14 rehabilitation hospitals scoring >0 on the Catherine Bergego Scale (N=312). The median age was 69.5 years, including 152 (49%) female patients and 275 (88%) patients with stroke.

Interventions

Patients were matched 1:1 by age (±5 years), FIM score at admission (±2 points), and SN severity using the Catherine Bergego Scale (±2 points) and classified into 2 groups: treated (8-12 daily sessions of PAT) vs untreated (no PAT).

Main Outcome Measures

FIM and its minimal clinically important difference (MCID) were the primary outcome variables. Secondary outcome was home discharge.

Results

Analysis included the 312 matched patients (156 per group). FIM scores at discharge were analyzed using repeated-measures analyses of variance. The treated group showed reliably higher scores than the untreated group in Total FIM, F=5.57, P=.020, partial η²=0.035, and Cognitive FIM, F=19.20, P<.001, partial η²=0.110, but not Motor FIM, F=0.35, P=.553, partial η²=0.002. We used conditional logistic regression to examine the odds ratio of reaching MCID in each FIM score and of returning home after discharge. No reliable difference was found between groups in reaching MCID or home discharge.

Conclusions

Patients with SN receiving PAT had better functional and cognitive outcomes, suggesting that integrating PAT into the standard of care is beneficial. However, receiving PAT may not determine home discharge.

Prism adaptation treatment for spatial neglect post brain tumour removal: A case report

Purpose/aim:

Spatial neglect is caused by damage to neural networks critical for spatial attention. Spatial neglect without proper treatment impedes rehabilitation outcomes. Prism adaptation treatment, a visuomotor protocol, has been used with stroke survivors with spatial neglect to improve function. This case report explored the feasibility and potential effects of prism adaptation treatment in an individual with spatial neglect after glioblastoma removal.

Methods

Feasibility was designed and tested to include acceptability and implementation. Exploratory aim on the effectiveness of the intervention was determined using the Catherine Bergego Scale via the Kessler Foundation Neglect Assessment Process, star cancellation, line bisection and scene copying.

Results

The patient reported favouring the treatment. Eight sessions, one session a day, were completed over two weeks. The patient’s spatial neglect symptoms reduced on all assessments.

Conclusion

Prism adaptation treatment was feasible and effective; however, further research is needed to understand the complete benefits of prism adaptation treatment in this population.

Applications of Functional Magnetic Resonance Imaging in Determining the Pathophysiological Mechanisms and Rehabilitation of Spatial Neglect

Functional magnetic resonance imaging (fMRI) is a neuroimaging tool which has been applied extensively to explore the pathophysiological mechanisms of neurological disorders. Spatial neglect is considered to be the failure to attend or respond to stimuli on the side of the space or body opposite a cerebral lesion. In this review, we summarize and analyze fMRI studies focused specifically on spatial neglect. Evidence from fMRI studies have highlighted the role of dorsal and ventral attention networks in the pathophysiological mechanisms of spatial neglect, and also support the concept of interhemispheric rivalry as an explanatory model. fMRI studies have shown that several rehabilitation methods can induce activity changes in brain regions implicated in the control of spatial attention. Future investigations with large study cohorts and appropriate subgroup analyses should be conducted to confirm the possibility that fMRI might offer an objective standard for predicting spatial neglect and tracking the response of brain activity to clinical treatment, as well as provide biomarkers to guide rehabilitation for patients with SN.

Multisensory stimulation for the rehabilitation of unilateral spatial neglect

Unilateral spatial neglect (USN) is a neuropsychological syndrome, typically caused by lesions of the right hemisphere, whose features are the defective report of events occurring in the left (contralesional) side of space and the inability to orient and set up actions leftwards. Multisensory integration mechanisms, largely spared in USN patients, may temporally modulate spatial orienting. In this pilot study, the effects of an intensive audio-visual Multisensory Stimulation (MS) on USN were assessed, and compared with those of a treatment that ameliorates USN, Prismatic Adaptation (PA). Twenty USN stroke patients received a 2-week treatment (20 sessions, twice per day) of MS or PA. The effects of MS and PA were assessed by a set of neuropsychological clinical tests (target cancellation, line bisection, sentence reading, personal neglect, complex drawing) and the Catherine Bergego Scale for functional disability. Results showed that MS brought about an amelioration of USN deficits overall comparable to that induced by PA; personal neglect was improved only by MS, not by PA. The clinical gains of the MS treatment were not influenced by duration of disease and lesion volume, and they persisted up to one month post-treatment. In conclusion, MS represents a novel and promising rehabilitation procedure for USN.

Treatment of spatial neglect in clinical practice: A nationwide survey

OBJECTIVES

Clinical research has documented a range of evidence-based treatment approaches for spatial neglect (SN), but there is a lack of research on the implementation of treatment into clinical practice. The purpose of this study is to describe the current clinical practice of SN treatment across healthcare sectors including involved professions, methods, timing and sources of evidence.

MATERIAL AND METHODS

This is the second part of a nationwide, anonymous, open Internet survey that was conducted among healthcare professionals in Denmark on assessment and treatment of SN.

RESULTS

A total of 525 healthcare professionals participated in the survey of which 411 (78.3%) reported that SN treatment was provided at their workplace. Occupational and physiotherapist were most often involved in the treatment, most commonly characterized by training of activities of daily living (ADL), sensoric stimulation and cueing. Less frequently reported were evidence-based methods such as prism adaptation and visual scanning. The overall intensity of the SN treatment varied considerably across sectors and might consequently be inadequate. A minority of the participants consulted clinical research evidence in their choice of SN treatment approaches.

CONCLUSIONS

There is a profound lack of dissemination and translation of clinical research into current clinical practice, which unarguably leads to an underuse of evidence-based treatment approaches in SN rehabilitation. The results call for international multidisciplinary clinical guidelines for the treatment of SN at different stages of rehabilitation and the tailoring of treatment approaches to the individual patient.

Frontal lesions predict response to prism adaptation treatment in spatial neglect: A randomised controlled study

Spatial neglect commonly follows right hemisphere stroke. It is defined as impaired contralesional stimulus detection, response, or action, causing functional disability. While prism adaptation treatment is highly promising to promote functional recovery of spatial neglect, not all individuals respond. Consistent with a primary effect of prism adaptation on spatial movements, we previously demonstrated that functional improvement after prism adaptation treatment is linked to frontal lobe lesions. However, that study was a treatment-only study with no randomised control group. The current study randomised individuals with spatial neglect to receive 10 days of prism adaptation treatment or to receive only standard care (control group). Replicating our earlier results, we found that the presence of frontal lesions moderated response to prism adaptation treatment: among prism-treated patients, only those with frontal lesions demonstrated functional improvements in their neglect symptoms. Conversely, among individuals in the standard care control group, the presence of frontal lesions did not modify recovery. These results suggest that further research is needed on how frontal lesions may predict response to prism adaptation treatment. Additionally, the results help elucidate the neural network involved in spatial movement and could be used to aid decisions about treatment.

Neuroanatomical and behavioural factors associated with the effectiveness of two weekly sessions of prism adaptation in the treatment of unilateral neglect

Among the different interventions to alleviate the symptoms of unilateral neglect, prism adaptation (PA) appears especially promising. To elucidate the contribution of some neuroanatomical and behavioural factors to PA's effectiveness, we conducted a study combining neuropsychological and lesion mapping methods on a group of 19 neglect patients who underwent two sessions of PA during one week and assessed their improvement relative to the baseline until the following week (7-8 days later). Correlation analyses revealed a significant positive relationship between the magnitude of the proprioceptive after-effect and the improvement at the follow-up session in two perceptual tasks requiring motor responses. Conversely, no correlation was found between the proprioceptive after-effect and the improvement in a perceptual task with no motor involvement. This finding suggests that patients' potential to show a prism-related improvement in motor-related tasks might be indicated by the strength of their proprioceptive response (proprioceptive after-effect). As for the neuroanatomical basis of this relationship, subtraction analyses suggested that patients' improvement in perceptual tasks with high motor involvement might be facilitated by the integrity of temporo-parietal areas and the damage of frontal and subcortical areas.

The effects of prism glasses and intensive upper limb exercise on hemineglect, upper limb function, and activities of daily living in stroke patients: a case series

[Purpose] This study aimed to examine the effects of visual field with prism glasses, and intensive upper limb functional training on reduction of hemineglect and improvement in upper limb function and activities of daily living in three stroke patients with hemineglect. [Subjects] This study included three stroke patients hospitalized in a sanatorium. [Methods] Intervention treatment involving prism glass use for 12 hours and 30 minutes and paretic side upper limb training was conducted 5 days a week for 15 weeks. Three upper limb training tasks (hitting a balloon, passing through a ring, and reading a newspaper) were performed for 10 minutes each session, for a total of 30 minutes. Line by Section, Motor-Free Visual Perception Test-3 (MVPT-3), Manual Function Test (MFT), Box & Block Test (BBT), and Assessment of Motor and Process Skills (AMPS) were conducted before and after intervention. [Results] Subjects’ hemineglect decreased and upper limb function on the paretic side improved after intervention, which enhanced activities of daily living. [Conclusion] Prism glass use and paretic upper limb functional training effectively ameliorated stroke patients’ hemineglect and improved upper limb function. Future research should focus on prism glasses that provide a wide visual field for use in patients with different conditions.