Prioritizing Post-Stroke Attention Deficits in Rehabilitation: A Critical Component for Recovery?

I wish to draw the attention of physiotherapists who commonly concentrate on the restoration of motor function in post-stroke patients to the fact that improving attention can significantly facilitate motor rehabilitation.

Physiotherapists play a key role in the rehabilita-tion and support of stroke patients during the post-acute phase. They devise and monitor an appropriate rehabilitation program to address impairments after stroke, such as muscle stiffness, loss of coordination and sensation, joint contracture, and spasticity. Attention disorders like poor concentra-tion and distractibility are commonly perceived in survivors of stroke, reducing their quality of life and posing hurdles to their rehabilitation. Studies have examined undiagnosed attention disorders in post-stroke subjects, the severity of their cognitive impairments- specifically those related to attention, and the influence of factors such as time since stroke, the side and site of the brain lesion, and the overall quality of living in post-stroke subjects with attention issues. Attention problems often persist after stroke, with reported frequencies ranging from 31-35% to as high as 46-92% during the acute recovery phase.^1,2 It has been pointed out that the prevalence of attention disorders among post-stroke subjects in the acute stage ranges from 46% to 92%, and that these disorders persist for years in 20% to 50% of cases.³

In another study, 617 stroke survivors underwent Montreal cognitive assessment and assessments of perceptual-motor function, executive function, language, memory, and attention three and/or 18 months after stroke.⁴ The National Institutes of Health Stroke Scale (NIHSS) was used to assess the severity of the stroke. Likelihood ratio tests were used to analyze the stroke subtypes and the effects of time. The probability of post-stroke cognitive impairment after three months was 0.59, and after 18 months, it was 0.51. Strokes resulting from cardioembolism and large artery disease were associated with impairments in attention, whereas patients with small vessel disease showed no such impairment. Another study evaluated intensive and selective attention processes in 204 brain lesion patients and 42 healthy subjects.⁵ The subjects underwent three subtests of Go-No Go, Attentional Performance (TAP), Divided Attention and Alertness. About 44.4% of patients showed impairments in both selective and intensive attention. Only the intensive component was impaired in 5.6%. Deficits in selective tasks were found in 31.8%. right hemispheric lesion (RHL) patients showed higher impairments in phasic and tonic alertness than left hemispheric lesion (LHL) patients. Patients with total anterior circulation infarcts (TACI) were more severely affected than those with other stroke subtypes. The alertness test showed that chronic patients had a shorter reaction time (RT) than patients in the acute phase. In LHL patients, aphasia led to selective attention deficit. Impairment in selective attention and alertness related to unilateral neglect was seen in RHL patients. The results confirm that the right hemisphere is associated with the intensity of attention while the left hemisphere is linked to the selective aspects of attention functioning.

Loetscher et al., reviewed the studies on the quality of life and mood in post-stroke subjects with attention problems, how they carry on their daily activities, and whether cognitive rehabilitation is effective on attention.⁶ They identified six studies on post-stroke subjects with attention problems, comparing those who received cognitive rehabilitation with those who received conventional physiotherapy care. The researchers suggest that more research is needed to assess how attentional abilities can be sustained in daily life. Neural substrates which underly attention deficit in chronic subcortical stroke patients were studied by a combination of voxel-based lesion-symptom mapping (VLSM) and diffusion-tensor (DT) tractography.⁷ Visual attention function was assessed by a modified version of the attention network test. In stroke patients, the location of lesions connected with attention deficit were identified using VLSM. The impaired connections which were responsible for stroke were determined by DT tractography. Patients with chronic stroke exhibited prolonged reaction times (RT) for right-sided responses compared to control subjects. VLSM revealed that, in stroke patients, prolonged RT was associated with lesions in the right caudate nucleus and adjacent white matter following acute stroke. In contrast, lesions in the right thalamic and caudate-prefrontal pathways were identified in control subjects. The researchers concluded that attention impairment in subcortical right hemisphere stroke patients can be attributed to the lesions in thalamic-prefrontal and caudate-prefrontal pathways.

Medical News Today on August 28, 2013 reported that undiagnosed attention disorders might be found in the majority of stroke patients.⁸ Resear-chers from London Imperial College analyzed 110 stroke patients at Charing Cross Hospital, London comparing them to 62 normal participants. All the participants were given attention network test (ANT) and the researchers measured the patients’ orientation, alertness, and executive control. A computer game was used in the test. The brain performance of the participants was tested through MRI scans by voxel-lesion mapping approach. It was found that more than 50% of the stroke patients had undiagnosed attention disorders. The researchers also found that the attention disorder type was contingent upon the affected brain part. The frequency of post-stroke attention deficits was assessed uisng the Bells test, the Trails Making Test A/B, Paced Auditory Serial Addition Test (PASAT) and Integrated Auditory Visual Continuous Performance Test (IVA-CPT) in 94 three-week post stroke subjects.⁹ London Handicap Scale, Physical and Mental Component Summary scores (PCS and MCS), General Health Questionnaire-28, SF-36 (Short Form-36), Modified Rankin Scale, and Cognitive Failures Questionnaire (CFQ) were employed to assess wider functioning. The IVA-CPT results indicated that most participants were impaired or severely impaired, unlike the findings of other attention measures. The researchers concluded that attention deficits are commonly observed after stroke, although the reported frequency varied. They suggested that in rehabilitative efforts, attention should be the primary focus.

This review of literature on attention disorders following stroke reveals that, despite the high prevalence of attention impairments among stroke survivors, few studies have addressed these attention deficits. More research is needed to assess how attentional abilities can be sustained in daily life, and to what extent different types of attention problems may benefit from cognitive rehabilitation.

Conflict of Interest

Nil