Introduction: Hemispatial neglect is associated with poor rehabilitation outcomes, increased falls, depression, and decreased independence in everyday activities. Neglect is difficult to ameliorate and therefore more treatments are required to address neglect. Prism adaptation therapy has become a promising rehabilitation technique. It uses prism lenses that laterally shift the visual field to the right to bring spatial awareness to the neglected side.

Clinical Scenario: A 40-year-old female was admitted to the hospital 6 weeks ago with left sided weakness and altered consciousness. Initial NIH stroke scale on admission was 15. MRI with angiogram revealed an infarct to the right middle cerebral artery. Procedures were done and her status improved since her initial hospitalization. Currently, the patient has been in rehab for 3 weeks now and made improvements overall however, the patient has not improved in her ability to learn to adapt to her environment. She is unable to return to work, sit for long periods without left side support, and unable to ambulate and scan her environment on the left side.

PICO: Since neglect is a primary impairment affecting safety during functional tasks, prism adaptation therapy may be a promising treatment to help her negotiate her environment in a safe manner. In adults (> 19 years old) with hemi-neglect post stroke, is prism adaptation therapy effective in improving functional outcome?

Search Strategy: 

Inclusion criteria: (1) be an experimental study, (2) include participates older than 18 years of age, (3) include participants with right sided stroke with left hemineglect/unilateral neglect, (4) include prism adaptation therapy as an intervention, (5) assess functional/daily life activity tasks.

Exclusion criteria: (1) included participants with hemianopia without stroke, (2) included participants with a previous neurological or psychiatric disease, (3) compared prism adaptation therapy with another treatment intervention for stroke.

The keywords, ‘prism adaptation,’ ‘prism,’ and ‘neglect,’ were used in combination with each other to search for articles in CINAHL, OVID, and PubMed.

Results:

Abbreviations: N=number; SR= systematic review; RCT= randomized controlled trial; SE= significant effects; PA= prism adaptation; DB=downs and black; L= left; R= right; M= middle; C= center; Ex= experimental group; CO= control group; Tx= Treatment; BIT= Behavior Inattention test; BG= between group; f/u= follow up; NLD= Netherlands; ITA= Italy; M-F= Monday-Friday; WS= within subjects; BS= between subjects; BSIE= between subject interaction effect; AL(C)= Albert Line Cancellation; AUS= Australia; FIM= functional independence measure; CBS= Cathering Bergego Scale; TUG= time up and go; SSA= subjective straight ahead pointing; deg= degree; BB= balance board; CoP= center of pressure; ML= mediolateral; AP= anterioposterior; H/V sway= horizontal/vertical; EO= eyes open; EC= eyes closed.

Limitations:

• Functional outcomes varied between subjects
• Small studies, no blinding
• No control group, no randomization
• Statistical analysis was not measured or only provided for certain measures
• Results can only be generalized to short term effects
• No standardization in interventions or measures
• Significant results were found in studies with different interventions
• Neglect comprises of heterogeneous set of symptoms therefore no test can capture symptoms in all patients

Clinical Bottom Line: There is good to fair evidence with mixed results that suggest prism adaptation therapy may improve daily function in patients with hemi-neglect post stroke when measured with functional outcome measures. Due to the high variability between studies, more consistent research is needed to address the effects of prism adaptation training on functional outcome.

Application to Clinical Case Scenario: Published studies vary in study type, interventions, outcome measures, and research quality. However, due to the easy administration and low risk of PA, there is evidence of promising effects on functional outcome. Prism adaptation is worth a try especially since the patient has made improvements overall and is unable to negotiate her environment in a safe manner.

Intervention: Prism lens with optical shift > 10 degrees with 100 pointing tasks to two targets without visual feedback. Then > 30 pointing tasks to two targets without lenses to measure adaptation after effect. Treatment time will be 10-30 min five times a week in addition to individualized stroke intervention in rehab.

Functional task: ambulation and sitting balance

Functional outcome: FIM and TUG

References:

1. Champod AS, Frank RC, Taylor K, Eskes GA. The effects of prism adaptation on daily life activities in patients with visuospatial neglect: A systematic review. Neuropsychol Rehabil. 2016:1-24. doi: 10.1080/09602011.2016.1182032 [doi].
2. Keane S, Turner C, Sherrington C, Beard JR. Use of fresnel prism glasses to treat stroke patients with hemispatial neglect. Arch Phys Med Rehabil. 2006;87(12):1668-1672. doi: S0003-9993(06)01263-9 [pii].
3. Mancuso M, Pacini M, Gemignani P, et al. Clinical application of prismatic lenses in the rehabilitation of neglect patients. A randomized controlled trial. Eur J Phys Rehabil Med. 2012;48(2):197-208. doi: R3312526 [pii].
4. Nijboer TC, Olthoff L, Van der Stigchel S, Visser-Meily JM. Prism adaptation improves postural imbalance in neglect patients. Neuroreport. 2014;25(5):307-311. doi: 10.1097/WNR.0000000000000088 [doi].
5. Nys GM, de Haan EH, Kunneman A, de Kort PL, Dijkerman HC. Acute neglect rehabilitation using repetitive prism adaptation: A randomized placebo-controlled trial. Restor Neurol Neurosci. 2008;26(1):1-12