The proposed study aimed to determine if tDCS can help post-stroke patients with dysarthria.
A total of 9 Cantonese-speaking chronic post-stroke patients who are suffering from dysarthria was recruited and randomly divided into treatment group and sham group. For the treatment group, an anodal high-definition tDCS of 2 milliampere (mA) lasting for 15 minutes was delivered to the primary motor cortex (SM1) in 10 daily sessions during a 2-week period. For the sham tDCS group, the same setting of tDCS electrodes was applied on the scalp, but the stimulation only lasted for 30 sec in order to cause similar sensation on the scalp as the other group. Simultaneous to the tDCS stimulation, both groups will receive speech and voice therapy for 30 minutes. An array of outcome measures reflecting speech production ability including acoustic, kinematic, perceptual and self-perceptual qualities was obtained before and after stimulation. It was anticipated that post-stroke dysarthric patients will see improvement in speech production after stimulation. The results provided important insights into the effects of tDCS on articulatory movement in individuals with dysarthria post-stroke.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
9
2mA of tDCS was delivered to the orofacial area of the primary motor cortex (SM1) for 15 minutes. Speech therapy was delivered simultaneously.
2mA of tDCS was delivered to the orofacial area of the primary motor cortex (SM1) for 30 sec. Speech therapy was delivered simultaneously.
University of Hong Kong
Hong Kong, Hong Kong
Perceptual speech assessments
All participants were required to produce a sustained vowel /a/, repeated some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/), produce some single words, read a standard paragraph in Cantonese and had a two-minute conversation with the investigator. A professional grade microphone (SM58, Shure, USA) was used to record the speech production. Experienced speech-language pathologists blinded to the neurological condition and history of each participant analyzed the speech samples independently using a perceptual rating scale including 21 speech dimensions covering eight categories, including pitch, loudness, voice quality, resonance, rate, articulation, tone, and general impression. The speech samples were rated using a seven-point equal-appearing interval scale, with a "1" indicating within typical limit performance and a "7" severely deviated from the normal.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Acoustic measurement: Fundamental frequency (F0)
Fundamental frequency (F0) was obtained from sustained vowel phonation.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Acoustic measurement: Frequency perturbation (jitter %)
Frequency perturbation (jitter %) was obtained from sustained vowel phonation.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Acoustic measurement: Intensity perturbation (shimmer %)
Intensity perturbation (shimmer %) was obtained from sustained vowel phonation.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Acoustic measurement: Noise to harmonic ratio (NHR)
Noise to harmonic ratio (NHR) was obtained from sustained vowel phonation.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
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Acoustic measurement: Harmonic to noise ratio (HNR)
Harmonic to noise ratio (HNR) was obtained from sustained vowel phonation.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Kinematic measurement: Duration
The lip and tongue function during speech production were traced real time and objectively measured using an electromagnetic articulography. All participants were required to produce single-syllable real words of consonant-vowel (CV) construction at high level tone embedded in a carrier phrase and repeat some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/). A custom-written analysis programme was used to annotate and calculate the kinematic measures, including duration (ms), distance (mm), maximum velocity (mm/s), maximum acceleration (m/s2) and maximum deceleration (m/s2) in the approach (movement towards the upper lip/palate) and release (movement away from the upper lip/palate) phases along the z-axis, i.e., along the mid-sagittal plane.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Kinematic measurement: Distance
The lip and tongue function during speech production were traced real time and objectively measured using an electromagnetic articulography. All participants were required to produce single-syllable real words of consonant-vowel (CV) construction at high level tone embedded in a carrier phrase and repeat some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/). A custom-written analysis programme was used to annotate and calculate the kinematic measures, including duration (ms), distance (mm), maximum velocity (mm/s), maximum acceleration (m/s2) and maximum deceleration (m/s2) in the approach (movement towards the upper lip/palate) and release (movement away from the upper lip/palate) phases along the z-axis, i.e., along the mid-sagittal plane.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Kinematic measurement: Maximum velocity
The lip and tongue function during speech production were traced real time and objectively measured using an electromagnetic articulography. All participants were required to produce single-syllable real words of consonant-vowel (CV) construction at high level tone embedded in a carrier phrase and repeat some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/). A custom-written analysis programme was used to annotate and calculate the kinematic measures, including duration (ms), distance (mm), maximum velocity (mm/s), maximum acceleration (m/s2) and maximum deceleration (m/s2) in the approach (movement towards the upper lip/palate) and release (movement away from the upper lip/palate) phases along the z-axis, i.e., along the mid-sagittal plane.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Kinematic measurement: Maximum acceleration
The lip and tongue function during speech production were traced real time and objectively measured using an electromagnetic articulography. All participants were required to produce single-syllable real words of consonant-vowel (CV) construction at high level tone embedded in a carrier phrase and repeat some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/). A custom-written analysis programme was used to annotate and calculate the kinematic measures, including duration (ms), distance (mm), maximum velocity (mm/s), maximum acceleration (m/s2) and maximum deceleration (m/s2) in the approach (movement towards the upper lip/palate) and release (movement away from the upper lip/palate) phases along the z-axis, i.e., along the mid-sagittal plane.
Time frame: Change before and after tDCS stimulation at immediately post-treatment
Kinematic measurement: Maximum deceleration
The lip and tongue function during speech production were traced real time and objectively measured using an electromagnetic articulography. All participants were required to produce single-syllable real words of consonant-vowel (CV) construction at high level tone embedded in a carrier phrase and repeat some syllables (i.e., /pa/, /ta/, /ka/ and /pataka/). A custom-written analysis programme was used to annotate and calculate the kinematic measures, including duration (ms), distance (mm), maximum velocity (mm/s), maximum acceleration (m/s2) and maximum deceleration (m/s2) in the approach (movement towards the upper lip/palate) and release (movement away from the upper lip/palate) phases along the z-axis, i.e., along the mid-sagittal plane.
Time frame: Change before and after tDCS stimulation at immediately post-treatment