Stroke is the second cause of mortality and the second leading cause of disability worldwide. A stroke may impair perception, broadly intended as the ability to understand information from our senses, that allows us to experience and meaningfully interact with our environment. Indeed, although a perceptual disorder may affect one in five stroke survivors and contribute to increased dependence on others and poorer quality of life, perceptual impairments often go undetected and untreated in clinical practice, and even patients may be unaware of them, thus failing to understand their difficulties and, possibly, further destabilizing their self-confidence. Interventions to address perceptual disorders may include assessment and screening, rehabilitation, non-invasive brain stimulation, and pharmacological and surgical approaches. A recent Cochrane review, performed by Christine Hazelton and other authors, aims to assess the effectiveness of interventions aimed at improving post-stroke perceptual disorders, adopting the World Health Organization definition of perception as “specific mental functions of recognizing and interpreting sensory stimuli.” Their search, updated to August 2021, included studies addressing interventions aimed at improving disorders of hearing, smell, somatosensation, taste, touch, and visual perception in stroke survivors. They included only studies that randomly assigned patients either to the active intervention or to no treatment or to a control intervention (placebo, standard care, attention control) – randomized controlled trials (RCTs). The primary outcome was an improvement in the performance in activities of daily living. A strength of this review is that to ensure its meaningfulness to key stakeholders, a group of stroke survivors with perceptual disorders and of health professionals with expert clinical knowledge were involved throughout all stages. Of the 18 trials (541 participants, 535 with stroke), 7 addressed somatosensation (196 participants), 3 touch (70 participants), 7 vision (225 participants), and 1 mixed perceptual disorders (50 participants), while none addressed hearing, taste, and smell. Interventions primarily used a rehabilitative approach, aiming to restore participants’ impaired perceptual function. Data provided very low-quality evidence, insufficient to support generalizable conclusions about the effectiveness of any one intervention, for any of the considered perceptual impairments. As the authors state, “Absence of evidence is not evidence of absence, but at present it is not possible to make recommendations regarding specific interventions for specific senses nor specific disorders.” Thus, there is a strong need for researchers to develop well-designed, adequately-sized clinical trials addressing this topic, providing a detailed theoretical rationale for, and description of, the interventions and a clear description of the addressed perceptual disorders, while exploring key outcomes relevant to clinical and lived-experience stakeholders. 

Reference 

Hazelton C, Thomson K, Todhunter-Brown A, Campbell P, Chung CSY, Dorris L, Gillespie DC, Hunter SM, McGill K, Nicolson DJ, Williams LJ, Brady MC. Interventions for perceptual disorders following stroke. Cochrane Database of Systematic Reviews 2022, Issue 11. Art. No.: CD007039. DOI: 10.1002/14651858.CD007039.pub3.

by Francesca Cecchi