Poststroke Dysphagia Rehabilitation by Repetitive Transcranial Magnetic Stimulation: A Noncontrolled Pilot Study

Abstract

Poststroke dysphagia is frequent and significantly increases patient mortality. In two thirds of cases there is a spontaneous improvement in a few weeks, but in the other third, oropharyngeal dysphagia persists. Repetitive transcranial magnetic stimulation (rTMS) is known to excite or inhibit cortical neurons, depending on stimulation frequency. The aim of this noncontrolled pilot study was to assess the feasibility and the effects of 1-Hz rTMS, known to have an inhibitory effect, on poststroke dysphagia. Seven patients (3 females, age = 65 +/- 10 years), with poststroke dysphagia due to hemispheric or subhemispheric stroke more than 6 months earlier (56 +/- 50 months) diagnosed by videofluoroscopy, participated in the study. rTMS at 1 Hz was applied for 20 min per day every day for 5 days to the healthy hemisphere to decrease transcallosal inhibition. The evaluation was performed using the dysphagia handicap index and videofluoroscopy. The dysphagia handicap index demonstrated that the patients had mild oropharyngeal dysphagia. Initially, the score was 43 +/- 9 of a possible 120 which decreased to 30 +/- 7 (p < 0.05) after rTMS. After rTMS, there was an improvement of swallowing coordination, with a decrease in swallow reaction time for liquids (p = 0.0506) and paste (p < 0.01), although oral transit time, pharyngeal transit time, and laryngeal closure duration were not modified. Aspiration score significantly decreased for liquids (p < 0.05) and residue score decreased for paste (p < 0.05). This pilot study demonstrated that rTMS is feasible in poststroke dysphagia and improves swallowing coordination. Our results now need to be confirmed by a randomized controlled study with a larger patient population.

Effects of Bilateral Repetitive Transcranial Magnetic Stimulation on Post-Stroke Dysphagia

“…Applying 3 Hz [7] and 10 Hz [8] rTMS over the cortical representation of the esophageal or mylohyoid muscle in the ipsilesional hemisphere showed a significant improvement as compared to the sham stimulation in dysphagia after stroke. On the other hand, both 1 Hz [9,10] rTMS and 5 Hz [11] rTMS at the contralesional motor cortex over the cortical representative of the pharyngeal or mylohyoid muscles showed an improvement on the swallowing function. Moreover, depending on the stimulating site, previous systematic reviews reported different results regarding the effect of non-invasive brain stimulation (NIBS).…”

“…Using a TMS System (Magstim Rapid2 ® stimulator, the Magstim Company Ltd., Wales, UK) and a 70-mm figure-of-eight coil, the optimal site for cortical areas on the corticobulbar projection to mylohyoid muscles in bilateral hemispheres was first determined using the maximal stimulator output. The coil was then positioned 2-4 cm anteriorly and 4-6 cm laterally apart from the vertex and moved around within the area to obtain the maximal motor evoked potential (MEP) responses in order to locate the mylohyoid hot spot area [10,15,16]. After the hot spot was determined, the resting motor threshold (RMT) was obtained by delivering single-pulse TMS to the hot spot at the submaximal stimulator output.…”

Sensory Transcutaneous Electrical Stimulation Improves Post-Stroke Dysphagic Patients

“…A new, conceptual approach involving noninvasive cortical stimulations [4] is a powerful method for modulating human brain function [5][6][7]. Another approach uses peripheral electrical stimulation, which is broadly employed in physiotherapy.…”

Transcranial Magnetic Stimulation as an Intervention Tool to Recover from Language, Swallowing and Attentional Deficits after Stroke: A Systematic Review

“…Moreover, applying rTMS in the early phase can be a source of bias when interpreting the intervention results, since patients frequently recover their swallowing abilities in this stage by natural mechanisms [18]. rTMS was applied to the oesophageal cortical representation area [6,19], pharyngeal motor cortex [18], suprahyoid muscle cortical area [7], mylohyoid cortical area [17,38,39], tongue cortical area [16] or abductor pollicis brevis cortical area [7]. A great difference between protocols was observed.…”

“…A great difference between protocols was observed. Studies applied low-frequency rTMS to suppress the nonlesioned hemisphere [17,38], or high-frequency to facilitate the excitability of either the unaffected [18], the affected [6,7,16,17] or even both hemispheres simultaneously [19]. Park et al [39] set up a treatment group where patients received high-frequency rTMS (HF-rTMS) over mylohyoid cortical area of the affected hemisphere followed by the same protocol over the unaffected hemisphere and a group receiving HF-rTMS to the affected hemisphere and sham stimulation on the unaffected hemisphere.…”