W19- Speech Production & Rehabilitation

What are the main stages of speech production before articulation? Conceptualisation, lemma retrieval, morphological encoding, phonological encoding, phonetic encoding, and articulation.

Which stage of speech production was the focus of this lecture? Articulation (physical production of speech).

What is a Brain-Computer Interface (BCI)? A system that measures brain activity, extracts relevant features, and converts them into outputs that replace or restore function.

What lost function can BCIs potentially restore in speech research? The ability to communicate through speech.

What are the four main steps of a BCI? Measure brain activity, extract features, convert features into outputs, restore/improve function.

What is the Stentrode? A brain-computer interface implanted within blood vessels rather than directly into brain tissue.

What is a major advantage of the Stentrode over traditional BCIs? It avoids invasive brain surgery and may reduce immune responses.

Why might the Stentrode be more scalable clinically? It can potentially be implanted by specialists trained in catheterisation rather than neurosurgeons.

What famous neuroscience method provided early causal evidence about speech production areas? Electrical cortical stimulation by Penfield and Boldrey (1937).

What happened when Penfield stimulated certain cortical areas? Vocalisations such as sustained or interrupted vowel sounds were produced.

Which cortical region is strongly associated with speech motor control? The precentral gyrus (primary motor cortex).

What did Penfield find when stimulating speech areas during speaking? Speech production could be disrupted or interrupted.

What does this suggest about speech production? It depends on a distributed neural network.

What is the role of the primary motor cortex in speech? Execution of speech movements.

What is the role of the premotor cortex in speech? Planning speech movements.

What is the role of the supplementary motor area (SMA)? Coordination of complex speech sequences.

What is the role of the inferior frontal gyrus (IFG)? Speech planning and production.

What cortical area is often referred to as Broca's area? The left inferior frontal gyrus.

Which cortical area provides sensory feedback during speech? The somatosensory cortex.

What is the pathway from cortex to speech muscles? Cortex → Thalamus → Midbrain → Brainstem → Cranial nerves → Articulators/Larynx.

Why are cranial nerves important for speech? They control speech muscles and the larynx.

What is auditory feedback? Hearing your own speech while producing it.

Why is auditory feedback important? It allows monitoring and correction of speech output.

What is Delayed Auditory Feedback (DAF)? Hearing your own voice played back after a short delay.

What effect does DAF have on most non-stutterers? It disrupts fluent speech and causes disfluencies.

What speech-production app demonstrates DAF effects? Speech Jammer.

What is the normal auditory feedback delay? Approximately 0.001 seconds.

At approximately what delay does speech disruption occur in adults? Around 0.2 seconds (200 ms).

What brain regions become more active during DAF? Bilateral temporoparietal regions.

Why do temporoparietal regions activate during DAF? Conscious self-monitoring is recruited.

What does DAF reveal about speech production and perception? They are tightly interconnected systems.

How does DAF affect people who stutter? It often improves speech fluency.

What delay is most effective for reducing stuttering? About 50 milliseconds.

What is the choral speech effect? Speaking in synchrony with another voice reduces stuttering.

Why might DAF help stutterers? The delayed voice is perceived as a second speaker, producing a choral speech effect.

What are limitations of DAF interventions? Benefits often do not persist, speech may sound unnatural, and integration into daily life is difficult.

What brain region is consistently underactive in people who stutter? The left inferior frontal gyrus.

Which study combined tDCS and speech therapy for stuttering? Chesters et al. (2018).

Where was tDCS applied in Chesters et al. (2018)? Over the left inferior frontal cortex.

How long was stimulation applied in Chesters et al. (2018)? 20 minutes per day for 5 consecutive days.

What was the main finding of Chesters et al. (2018)? tDCS combined with behavioural intervention reduced speech disfluency and effects persisted up to 6 weeks.