Key messages
Stroke can affect a person’s ability to process and understand information from their senses, including hearing, smell, somatosensation (sense of body temperature, position, and movement), taste, touch, and vision. Processing and understanding information from these senses is known as perception.
Little research has been carried out to find out whether any treatments for stroke-related problems with perception are helpful.
People with stroke-related problems with hearing, smell, somatosensation, taste, touch, and vision should continue to participate in rehabilitation as recommended by clinical guidelines. Healthcare professionals should continue to offer rehabilitation for stroke-related perceptual problems in keeping with current clinical guidelines and recommendations.
What is a perceptual disorder?
Before a stroke, adults gather information about the world through their senses: hearing, smell, somatosensation, taste, touch, and vision. Somatosensation refers to sensation arising from the skin, muscles, or joints, and includes perception of pressure, vibration, temperature, and position. Information gathered might include the colour, shape, and size of objects that they see. Together with memories and cultural experiences, a person can understand how someone is feeling from seeing their facial expression. Other examples are how different odours can be identified through the sense of smell and how different textures can be felt through the sense of touch. A stroke can affect these abilities.
How are perceptual disorders treated?
Healthcare professionals, including occupational therapists, physiotherapists, and psychologists, may offer different therapies. Treatments might include medicine, stimulation of the brain, or perceptual rehabilitation through activities, puzzles, strategies, or intensive repetition of tasks.
What did we want to find out?
We wanted to find out whether receiving any perceptual disorder treatment was better than no treatment at all. We measured improvement by looking at how well people could carry out their daily activities. We measured whether treatments also helped other things, such as quality of life, mental health, and perception. We looked for information on when things did not go well. We also explored whether one treatment was more beneficial than another.
What did we do?
We searched for all relevant research. We assessed the quality of 18 studies and summarised their results.
What did we find out?
The studies we found were about different perceptual disorders: three studies looked at disorders of touch perception, seven looked at somatosensation, seven studies looked at vision, and one looked at several perceptual problems at the same time. The treatments used in these studies included paper-and-pencil copying tasks to improve visual memory and using robots to help improve a person’s sense of where their body is positioned. We found no information to show that any treatment worked.
Why are we still uncertain?
We found few studies. Each study included a small number of people with a perceptual problem after a stroke. With small numbers of people involved, the results were not clear. Each study looked at different interventions. Less than half the studies (seven) measured the ability to carry out everyday activities.
How up to date is this information?
Our information is up to date as of August 2021.
Based on the information we gathered, we are still unclear about the benefits or harms of treatments for perceptual problems after stroke. People with perceptual problems after stroke should continue to be offered rehabilitation as recommended in clinical guidelines.
Following a detailed, systematic search, we identified limited RCT evidence of the effectiveness of interventions for perceptual disorders following stroke. There is insufficient evidence to support or refute the suggestion that perceptual interventions are effective. More high-quality trials of interventions for perceptual disorders in stroke are needed. They should recruit sufficient participant numbers, include a 'usual care' comparison, and measure longer-term functional outcomes, at time points beyond the initial intervention period. People with impaired perception following a stroke should continue to receive neurorehabilitation according to clinical guidelines.
Perception is the ability to understand information from our senses. It allows us to experience and meaningfully interact with our environment. A stroke may impair perception in up to 70% of stroke survivors, leading to distress, increased dependence on others, and poorer quality of life. Interventions to address perceptual disorders may include assessment and screening, rehabilitation, non-invasive brain stimulation, pharmacological and surgical approaches.
To assess the effectiveness of interventions aimed at perceptual disorders after stroke compared to no intervention or control (placebo, standard care, attention control), on measures of performance in activities of daily living.
We searched the trials registers of the Cochrane Stroke Group, CENTRAL, MEDLINE, Embase, and three other databases to August 2021. We also searched trials and research registers, reference lists of studies, handsearched journals, and contacted authors.
We included randomised controlled trials (RCTs) of adult stroke survivors with perceptual disorders. We defined perception as the specific mental functions of recognising and interpreting sensory stimuli and included hearing, taste, touch, smell, somatosensation, and vision. Our definition of perception excluded visual field deficits, neglect/inattention, and pain.
One review author assessed titles, with two review authors independently screening abstracts and full-text articles for eligibility. One review author extracted, appraised, and entered data, which were checked by a second author. We assessed risk of bias (ROB) using the ROB-1 tool, and quality of evidence using GRADE.
A stakeholder group, comprising stroke survivors, carers, and healthcare professionals, was involved in this review update.
We identified 18 eligible RCTs involving 541 participants. The trials addressed touch (three trials, 70 participants), somatosensory (seven trials, 196 participants) and visual perception disorders (seven trials, 225 participants), with one (50 participants) exploring mixed touch-somatosensory disorders. None addressed stroke-related hearing, taste, or smell perception disorders. All but one examined the effectiveness of rehabilitation interventions; the exception evaluated non-invasive brain stimulation. For our main comparison of active intervention versus no treatment or control, one trial reported our primary outcome of performance in activities of daily living (ADL):
Somatosensory disorders: one trial (24 participants) compared an intervention with a control intervention and reported an ADL measure.
Touch perception disorder: no trials measuring ADL compared an intervention with no treatment or with a control intervention.
Visual perception disorders: no trials measuring ADL compared an intervention with no treatment or control.
In addition, six trials reported ADL outcomes in a comparison of active intervention versus active intervention, relating to somatosensation (three trials), touch (one trial) and vision (two trials).