Description

Unilateral spatial neglect (USN) is a common and disabling consequence of stroke, particularly following right-hemisphere lesions, affecting up to 50-70% of survivors. USN impairs a patient's ability to attend to or interact with stimuli on the side opposite the brain lesion, leading to significant challenges in daily functioning and rehabilitation engagement. The presence of USN is associated with poorer functional outcomes, increased dependence, and prolonged recovery after a stroke. Prism Adaptation Training (PAT) is a non-invasive intervention that has emerged as a promising approach for USN rehabilitation. PAT involves repeated visuomotor activities while wearing prism glasses that shift the visual field, promoting adaptation and recalibration of spatial attention. Multiple studies and systematic reviews have demonstrated that PAT can improve neglect symptoms, enhance motor control of the affected limb, and improve activities of daily living (ADL), with effects persisting for weeks to months post-intervention. However, the optimal dosing, duration, and potential for augmenting the effects of PAT remain areas of ongoing investigation. Transcutaneous Electrical Nerve Stimulation (TENS) is another non-invasive modality widely used in post-stroke rehabilitation. TENS delivers mild electrical currents through the skin to stimulate nerves and has shown efficacy in improving motor function, reducing spasticity, and enhancing functional recovery in stroke survivors. It has been shown to enhance upper limb function in individuals who have experienced a stroke. While TENS is primarily used for motor and sensory rehabilitation, its potential to modulate cortical excitability and facilitate neuroplasticity suggests it may also influence cognitive domains, including attention and spatial processing. There is evidence suggesting that TENS can have an impact on neglect. Despite the individual benefits of PAT and TENS in post-stroke rehabilitation, limited research has explored their combined effects on USN. The rationale for pairing PAT with TENS is based on the hypothesis that TENS-induced sensory stimulation may help enhance awareness of neglected space when applied to the upper extremity of individuals experiencing neglect, thereby potentially amplifying the adaptive effects of PAT on spatial neglect. However, the synergistic potential of TENS to enhance cognitive-perceptual rehabilitation strategies like PAT in the context of USN has not been systematically investigated. Given the persistent functional burden of USN and the need for more effective and accessible rehabilitation protocols, a pilot study comparing PAT paired with TENS versus PAT alone could provide critical preliminary evidence. Such research may identify whether adjunctive TENS can accelerate or enhance recovery from neglect, inform optimal intervention strategies, and ultimately improve independence and quality of life for stroke survivors experiencing USN.

The research question:

Is the combination of Prism Adaptation Therapy (PAT) and Transcutaneous Electrical Nerve Stimulation (TENS) more effective than PAT alone in reducing unilateral spatial neglect (USN) in individuals' post-stroke?

Hypothesis: The combination of Prism Adaptation Therapy (PAT) and Transcutaneous Electrical Nerve Stimulation (TENS) will be more effective than PAT alone in reducing unilateral spatial neglect (USN) in individuals post-stroke.

Primary study aim:

To evaluate whether the combination of Prism Adaptation Therapy (PAT) and Transcutaneous Electrical Nerve Stimulation (TENS) is more effective than PAT alone in reducing unilateral spatial neglect (USN) in individuals post-stroke.

Secondary study aims: To investigate whether patient characteristics (e.g. time since stroke, lesion location, severity of neglect, gender, age) influence the effectiveness of the combined intervention. To investigate the effects of the PAT alone and the combined PAT and TENS intervention on functional outcomes related to USN. To investigate the impact of PAT alone and the combined PAT and TENS intervention on the motor control of the neglected limb.

The main study outcome measures include:

The Catherine Bergego Scale (CBS) is the selected outcome measure for assessing the severity of Unilateral Spatial Neglect (USN) and for evaluating changes in function and neglect following interventions. The CBS includes 10 subtests designed to identify both the presence and severity of USN. All occupational therapists at the NeuroRehab and Balance Center (NRBC) have been trained in the proper administration and scoring of the CBS to ensure accurate results. It is standard protocol at NRBC clinic that all patients diagnosed with stroke are evaluated for potential USN using the CBS, which is routinely administered in these cases. In 2014, the Kessler Foundation published guidelines on how to administer the CBS.

The Wolf Motor Function Test (WMFT) is a standardized assessment tool widely used to measure upper extremity motor abilities in individuals recovering from a stroke. This test serves as an outcome measure for motor control, helping to assess improvements in movement quality and reaction time following interventions. All occupational therapists at the NeuroRehab and Balance Center (NRBC) have received training in the administration and scoring of the WMFT, and it is standard protocol at NRBC that all patients diagnosed with stroke are evaluated using the WMFT.