None listed
Conditions
Brief summary
Stroke is a leading cause of adult disability, affecting around six thousand New Zealanders each year. Somatosensory and motor impairment are common after stroke. We and others have recently found that the spontaneous recovery of motor impairment after stroke is usually proportional to the degree of initial impairment. Patients recover 70% of what they have lost, provided the corticospinal tract remains functional. This 70% rule holds true for patients of both genders, all ages, and regardless of therapy dose. There must be a fundamental neurobiological process at work, with which current rehabilitation practices do not interact. The present study will extend our previous work by determining whether spontaneous recovery of sensory impairment after stroke is also proportional to initial impairment. We will recruit up to 80 patients with recent stroke and make longitudinal measures of sensory and motor impairment to map recovery trajectory. The recovery trajectories for sensory and motor impairments will be compared to see whether the rates of improvement are similar within patients. This would provide further support for the idea that spontaneous recovery is due to a fundamental neurobiological mechanism, which proceeds at the same rate across functional domains within a given patient. We will use neurophysiology and neuroimaging techniques to test the idea that spontaneous recovery is related to restoration of neurotransmission in key white matter pathways in the brain. Somatosensory evoked potentials will be recorded to evaluate the functional integrity of the dorsal column medial lemniscus tract, and motor evoked potentials will be used to evaluate the functional integrity of the corticospinal tract. Magnetic resonance imaging will be used to measure the extent of damage to ascending sensory and descending motor tracts. If we find that spontaneous recovery of sensory and motor impairment relies on the integrity of these tracts, restoration of neurotransmission will become an important therapeutic target for stroke rehabilitation research.
Interventions
None. This is an observational study with no intervention. Motor and sensory impairment will be evaluated weekly for the first four weeks post-stroke, then fortnightly until performance plateaus or six months post-stroke, whichever occurs first.
Motor assessments include the Fugl-Meyer scale, hand and pinch grip strength, Action Research Arm Test, and walking ability assessed with the Functional Ambulation Category. The Fugl-Meyer scale is a motor impairment assessment which involves performing
None. This is an observational study with no intervention. Motor and sensory impairment will be evaluated weekly for the first four weeks post-stroke, then fortnightly until performance plateaus or six months post-stroke, whichever occurs first. Motor assessments include the Fugl-Meyer scale, hand and pinch grip strength, Action Research Arm Test, and walking ability assessed with the Functional Ambulation Category. The Fugl-Meyer scale is a motor impairment assessment which involves performing a number of simple movements and reflexes of the upper and lower limbs. Hand grip and pinch grip tests will involve gripping a small instrument at maximum strength. The Action Research Arm Test evaluates hand and arm function by asking the patient to complete some simple tasks. The Functional Ambulation Category places the patient in one of six categories based on reported walking ability. Sensory assessments include light touch, spatial acuity and proprioception. Light touch involves lightly pressing a thin plastic filament to the base of the thumb and the participant responding when they feel a touch. Similarly, spatial acuity involves lightly pressing two blunt plastic points to the base of the thumb and the participant saying which orientation they are. Proprioception involves one hand being hidden from sight and moved by the experimenter to an angle on a protractor, and the participant is asked to match the angle with the other hand. Transcranial magnetic stimulation is a noninvasive brain stimulation technique which involves placing a plastic covered coil over the scalp. The coil creates a brief magnetic pulse that excites neurons in the area of the brain controlling movement. This can generate a motor evoked potential (MEP), recorded with surface electromyography. Peripheral nerve stimulation is a noninvasive stimulation technique which involves placing electrodes on the wrist, to activate the underlying ulnar nerve with brief pulses at an intensity 1.5 times perceptual threshold. Sensory processing of this sensation will be detected by using electroencephalography, which involves placing recording electrodes on the scalp to measure the N20 potential. Magnetic resonance imaging involves the participant lying down in a scanner while it runs for about 30 minutes. We will acquire T1 and diffusion-weighted images, to evaluate the stroke lesion and its effects on white matter integrity. There are no risks associated with any of the motor or sensory assessments. Transcranial magnetic stimulation and peripheral nerve stimulation may cause mild, transient discomfort of the scalp and wrist, respectively. The three neurophysiological techniques have a number of contraindications, which will be screened for prior to inclusion to the study.
Sponsors
The University of Auckland
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Aged 18 years or more Diagnosis of monohemispheric cerebral ischaemic or haemorrhagic stroke within the previous week Weakness and/or sensory loss on one side of the body as a result of stroke
Exclusion criteria
Cerebellar stroke Contraindications to non-invasive brain stimulation or MRI Pre-existing neurological or musculoskeletal condition affecting movement or sensation Cognitive and/or communication impairment precluding informed consent or compliance with testing procedures. Life expectancy less than 12 months Resides out of the Auckland region, precluding follow-up assessments
Outcome results
None listed