Patients experiencing communication problems after having a stroke could see long-term benefits from low-current electrical stimulation therapy, according to an international study led by The University of Queensland.
The therapy could revolutionise treatment for patients with aphasia, a common condition in those who have had a stroke, affecting the ability to speak, read, write and understand what others are saying.
Associate Professor Marcus Meinzer, from the UQ Centre for Clinical Research, said transcranial direct current stimulation was non-invasive and painless, and used a constant low current delivered to the brain via electrodes on the scalp.
“We worked with the Department of Neurology at the Charité University Hospital in Berlin, Germany, to test the benefits of transcranial direct current stimulation on stroke patients with aphasia,” Associate Professor Meinzer said.
“To test the therapy, we compared the language ability and everyday communications skills of two groups of stroke patients with aphasia.
“The first group received language therapy combined with transcranial direct current stimulation, while the second group received language therapy alone.”
He said the study showed for the first time that transcranial direct current stimulation could provide significant and lasting benefits for patients with chronic aphasia.
“While the therapy is commonly used in patients who have had a stroke, we have not had any evidence until now that transcranial stimulation has long-term benefits for patients with aphasia,” Associate Professor Meinzer said.
The team found a way to make the treatment easier and less expensive for patients and doctors.
“Until now, it has been standard practice for doctors to perform expensive scans of patients’ brains to see which areas need to be targeted for treatment,” Associate Professor Meinzer said.
“We used a new approach, targeting just one area of the brain – the motor cortex – for therapy.
He said the motor cortex acted as a bridge to reach parts of the language cortex in the brain left undamaged by stroke.
“By stimulating the motor cortex, we were able to stimulate the undamaged language regions in the brain and facilitate the development of language in affected patients.
“This approach which may help a significant portion of patients with aphasia to further improve their language – months, or even years, after having a stroke.
“Most importantly, it tells us that doctors do not have to scan patients individually to find which parts of the brain are affected by the stroke, and this will significantly reduce the cost and feasibility of treatment in the future.”
About this neurology research
Source:University of Queensland Image Source: Image is adapted from the University of Queensland press release. Original Research: Full open access research for “Electrical stimulation of the motor cortex enhances treatment outcome in post-stroke aphasia” by Marcus Meinzer, Robert Darkow, Robert Lindenberg, and Agnes Flöel in Brain. Published online February 16 2016 doi:10.1093/brain/aww002
Electrical stimulation of the motor cortex enhances treatment outcome in post-stroke aphasia
Transcranial direct current stimulation has shown promise to improve recovery in patients with post-stroke aphasia, but previous studies have only assessed stimulation effects on impairment parameters, and evidence for long-term maintenance of transcranial direct current stimulation effects from randomized, controlled trials is lacking. Moreover, due to the variability of lesions and functional language network reorganization after stroke, recent studies have used advanced functional imaging or current modelling to determine optimal stimulation sites in individual patients. However, such approaches are expensive, time consuming and may not be feasible outside of specialized research centres, which complicates incorporation of transcranial direct current stimulation in day-to-day clinical practice. Stimulation of an ancillary system that is functionally connected to the residual language network, namely the primary motor system, would be more easily applicable, but effectiveness of such an approach has not been explored systematically. We conducted a randomized, parallel group, sham-controlled, double-blind clinical trial and 26 patients with chronic aphasia received a highly intensive naming therapy over 2 weeks (8 days, 2 × 1.5 h/day). Concurrently, anodal-transcranial direct current stimulation was administered to the left primary motor cortex twice daily at the beginning of each training session. Naming ability for trained items (n = 60 pictures that could not be named during repeated baseline assessments), transfer to untrained items (n = 284 pictures) and generalization to everyday communication were assessed immediately post-intervention and 6 months later. Naming ability for trained items was significantly improved immediately after the end of the intervention in both the anodal (Cohen’s d = 3.67) and sham-transcranial direct current stimulation groups (d = 2.10), with a trend for larger gains in the anodal-transcranial direct current stimulation group (d = 0.71). Treatment effects for trained items were significantly better maintained in the anodal-transcranial direct current stimulation group 6 months later (d = 1.19). Transfer to untrained items was significantly larger in the anodal-transcranial direct current stimulation group after the training (d = 1.49) and during the 6 month follow-up assessment (d = 3.12). Transfer effects were only maintained in the anodal-transcranial direct current stimulation group. Functional communication was significantly more improved in the anodal-transcranial direct current stimulation group at both time points compared to patients treated with sham-transcranial direct current stimulation (d = 0.75–0.99). Our results provide the first evidence from a randomized, controlled trial that transcranial direct current stimulation can improve both function and activity-related outcomes in chronic aphasia, with medium to large effect sizes, and that these effects are maintained over extended periods of time. These effects were achieved with an easy-to-implement and thus clinically feasible motor-cortex montage that may represent a promising ‘backdoor’ approach to improve language recovery after stroke.
“Electrical stimulation of the motor cortex enhances treatment outcome in post-stroke aphasia” by Marcus Meinzer, Robert Darkow, Robert Lindenberg, and Agnes Flöel in Brain. Published online February 16 2016 doi:10.1093/brain/aww002