In this proof-of-concept pilot study, transcranial direct current stimulation (tDCS) was used as an adjuvant to speech therapy in an intensive comprehensive aphasia program (ICAP).
Using a double-blind, sham controlled, between-group design, 1 mA of direct current was delivered via NEO-24 PiStim gel electrodes using a Starstim tDCS device.The anode was placed over the inferior frontal gyrus (FC5), with the cathode placed over the supra-orbital frontal area (AF8) of the contralesional side during the first 20 minutes of daily intensive speech therapy for a period of 15 consecutive weekdays, commencing on day-1 of an 8-week ICAP. Pre- and post-treatment standardized assessments and discourse analysis, as well as bi-weekly trained and untrained probes, were used as outcome measures.
Six subjects were analyzed; three received ICAP-tDCS and three received ICAP-sham. Five subjects were male. Ages ranged from 50 to 67 years. Time post-stroke at enrollment ranged from 8 months to 5.2 years. Subjects receiving ICAP-tDCS treatment demonstrated significantly higher improvement than ICAP-sham patients on the Boston Naming Test ( p=0.05), trained and untrained probes (p=0.05, untrained absolute increase p=0.05, percent increase p=0.38), and picture-description discourse (absolute increase p=0.05, percent increase p=0.38). There was no difference in the improvement of Western Aphasia Battery-AQ between ICAP-tDCS and ICAP-sham patients (absolute and percent increases both p=0.28). No adverse effects of tDCS or intensive behavioral training were reported. Following completion of the initial 3 weeks of adjunctive tDCS and tDCS-sham treatment, all subjects continued participation in the ICAP therapy with behavioral intervention only, and concluded the 8-week program.
In this proof-of-concept pilot rehabilitation study, we demonstrate significant language improvements in chronic post-stroke aphasia, following intensive speech therapy combined with tDCS. Results should be confirmed in a larger randomized clinical trial.