The Effects of Brain Stimulation on Speech Fluency in Adults Who Stutter

The project is leading to investigate the effects of neuromodulation techniques on speech fluency among adults who stutter (AWS). While stuttering is responsive to a variety of treatments in childhood, this is not the case for AWS. Behavioural treatments to reduce stuttering for adults typically consist of speech restructuring methods, which involves the person using one of the altered speech patterns known to increase fluency, such as chorus reading, speaking in rhythm, and prolonging (smoothing/stretching out) speech sounds. Research has shown that behavioural interventions such as these change brain activation patterns in the regions associated with stuttering. Unfortunately, around 70% of AWS who receive these speech restructuring treatments do not maintain the benefits in the longer term and frequently re-present to speech clinics. The aim of this proposed research is to explore whether the brain stimulation using repetitive transcranial magnetic stimulation (rTMS) can consistently enhance effects of behavioural stuttering therapy by examining their responsiveness to the treatment across different outcome measures including a) immediate effect on different speaking contexts, and b) the maintenance of effects over one week after therapy.

This study uses a double-blinded between- and within-subjects crossover sham-controlled design across two different treatment phases to enhance the effects of behavioural training on stuttering.

The rTMS group will receive 30 minutes of excitatory rTMS (i.e., 60 trains of 10 Hz pulses for 5 second with over 120% of motor threshold) over SMA combined with speech training (for 25 seconds during the 60 inter-train intervals) for five sessions

The sham group will receive 30 minutes of sham rTMS (no magnetic stimulation) over SMA combined with speech training (for 25 seconds during the 60 inter-train intervals) for five sessions.

TMS stimulation produce electromagnetic pulses that can directly changes the neural firing in the brain. The rTMS applies the magnetic pulses in a repetitive manner, and can induce either an inhibitory or excitatory effect on cortical neurons. In this study we use high frequency rTMS (10 Hz) to provide the excitatory effect.

The behavioural training will include reading sentences in which a syllable is spoken in time to a rhythmic beat.

For the assessment of subject satisfaction regarding the treatment, the following two Likert-type survey questions will be asked at weeks 1 post-treatment, to which the participants will respond: (1) How much do you think the treatment helped you to speak more fluently? (1 = not at all, 2 = a little, 3 = somewhat, 4 = a lot, 5 = totally); and (2) How often/much do you think the treatment helped you to feel less stressed in your communication? (1 = never or not at all, 2 = rarely or a little, 3 = sometimes or somewhat, 4 = often or a lot, 5 = always or totally).

Inclusion Criteria: - adults who stutter without any other speech, language or cognitive problems Exclusion Criteria: have any history of neurological and other speech and language problems condition that are violating the safety criteria for TMS any history of epilepsy, and brain damage, having any metal plant or cardiac pace-maker in the body, current pregnancy