Anomia training and brain stimulation in chronic aphasia

Abstract

Recent studies have reported enhanced performance on language tasks induced by non-invasive brain stimulation, i.e., repetitive transcranial magnetic stimulation (rTMS), or transcranial direct current stimulation (tDCS), in patients with aphasia due to stroke or Alzheimer's disease (AD). The first part of this article reviews brain stimulation studies related to language recovery in aphasic patients. The second part reports results from a pilot study with three chronic stroke patients who had non-fluent aphasia, where real or placebo rTMS was immediately followed by 25 minutes of individualised speech therapy. Real rTMS consisted of high-frequency rTMS over the left dorsolateral prefrontal cortex (BA 8/9) for 25 minutes. Each patient underwent a total of four weeks of intervention. P1 underwent four weeks of real rTMS (5 days/week) where individualised speech therapy was provided for 25 minutes immediately following each rTMS session. P2 and P3 each underwent two weeks of placebo rTMS, followed immediately by individualised speech therapy; then two weeks of real rTMS, followed immediately by individualised speech therapy. Assessments took place at 2, 4, 12, 24 and 48 weeks post-entry/baseline testing. Relative to entry/baseline testing, a significant improvement in object naming was observed at all testing times, from two weeks post-intervention in real rTMS plus speech therapy, or placebo rTMS plus speech therapy. Our findings suggest beneficial effects of targeted behavioural training in combination with brain stimulation in chronic aphasic patients. However, further work is required in order to verify whether optimal combination parameters (rTMS alone or speech therapy alone) and length of rTMS treatment may be found.

Evidence For the Use of Transcranial Magnetic Stimulation As An Effective Therapeutic Option For Aphasia

“…Cotelli et al provided the first case study evidence to demonstrate that high-frequency, 20-Hz, rTMS to the left dorsolateral prefrontal cortex in left hemisphere lesioned chronic nonfluent aphasic patients can be used to improve language performance [4]. Two patients received 2 weeks of active stimulation and 2 weeks of placebo stimulation and one patient received 4 weeks of active stimulation.…”

“…Investigations range from chronically impaired aphasic patients (at least 6 months post-stroke) [1][2][3][4][5] to subacute populations (2-7 weeks poststroke) [6]. The most promising language outcomes post-TMS reported to date report improvements in picture naming and expressive language function.…”

“…Nonetheless, evidence available to date mainly consists of case-based reports [3][4][5]7], complemented by a small number of placebo-controlled trials [1,2,6] and is thus still considered rudimentary and largely inadequate to draw decisive conclusions regarding its therapeutic efficacy. It is widely acknowledged, however, that TMS has a highly valuable clinical application to stroke, and potentially, to other brain injured populations with acquired language disorders and even motor speech disorders.…”

“…Both high-and low-frequency forms of rTMS, including theta burst stimulation, have been applied to patients with aphasia, with positive longitudinal reports for language outcomes [1][2][3][4][5][6][7]. Investigations range from chronically impaired aphasic patients (at least 6 months post-stroke) [1][2][3][4][5] to subacute populations (2-7 weeks poststroke) [6].…”

“…With this in mind, the direct manipulation of cortical brain activity by repetitive TMS (rTMS) is posited as an efficacious complimentary rehabilitatory treatment for patients with post-stroke aphasia. Prospectively, rTMS may aid in the alleviation of some language disturbances associated with post-stroke aphasia via the reorganization of neural language networks [1][2][3][4][5][6][7].…”