Speech And Communication Disorders beyond Aphasia Flashcards
Neuroanatomical structure involved in speech
- Broca’s are
- arcuate fasiculus
- supramarginal gyrus
- primary auditory cortex
- secondary auditory cortex
- Wernicke’s area
- angular gyrus
- Language areas: mostly irrespective of medium (speech, writing, reading, hand gesturing) –> distinct areas for those functions
- elements of communication: rules (grammar), order (syntax), emotional valence (prosody)
=> language network is distributed through brain
- left hemisphere emphasis for majority
What does Broca’s area do?
- speech production
- fluency and action
- planning and initiation
- sequencing and corrdination
- monitoring and fine tuning
What does the arcuate fasiculus do?
- information transfer between Wernicke’s (angular gyrus, supra marginal gyrus) and Broca’s area
What does the supramarginal gyrus do?
- phonological processing
- verbal working memory
- mapping sounds to meaning
- assist Broca’s area in speech production
What does the primary auditory cortex do?
- detection and processing of sound waves
- feature analysis
- frequency mapping
- indirect contribution to language comprehension
What does the secondary auditory cortex do?
- processing complexities of speech
- language learning
- sound differences in phonemes
What does Wernicke’s area do?
- comprehension
- decoding sound
- associating sound with meaning
- integrating information
What does the angular gyrus do?
- semantic integration
- multisensory integration
- reading comprehension
- inferencing
- pragmatics
Language and basal ganglia
Speech initiation
- Parkinson patients experience problems in starting speech and also speaking loud and clearly (muted, slurred speech)
Priming
- word are contextualised and the brain anticipates what words may follow as a result of experience
- Parkinson patients may have difficulties with words that have more than one meaning because of increased ambiguity (waker contextualisation
Language and amygdala
- recognising emotional content of speech
- particularly related to fear
Language and cerebellum
- parsing of heard speech
- coordination of the vocal apparatus
- cerebellar deficits may cause ‘scanning speech’
Frontal cortex
- has many functions serving selection, planning and execution of appropriate behaviours
–> especially in contexts, and maintaining ‘personality’ - input from sensory, motor and remporal association cortices
–> resulting in appreciation of self within the world - damage to PFC can lead to impaired recognition of social cues and awkward or impulsive behaviour
Amygdala, emotion and arousal
- is connected to several cortical areas (orbital and medial aspect of the frontal lobe)
- projects to mediodorsal thalamus and ventral portions of basal ganglia
- links together cortical and subcortical brain regions involved in emotion processing
–> networks are likely to influence selection and initiation of behaviours aimed at obtaining rewards and avoiding punishment - short and long term
What is a disorder?
= a group of symptoms involving abnormal behaviours or physiological conditions, persistent or intense distress or a disruption of physiological functioning
What is social cognition?
= cognition in which people perceive, think about, interpret, categorise and judge their own social behaviours and those of others
What is communication?
= transmission of information, which may be by verbal (oral or written) or nonverbal means (see nonverbal communication)
- humans communicate to relate and exchange ideas, knowledge, feelings, and experiences and for many other interpersonal social purposes
What is Autism?
= a neurodevelopmental disorder associated with deficits in soical communication
This includes deficits in:
- social-emotional reciprocity
- non-verbal communication
- developing and maintaining relationships
Other symptoms may include:
- restricted patterns or behaviours or interests
- repetitive motor movements
- differences in sensory processing
Neurobiology of autism
no singular ‘cause’ known –> BUT genetic factors play a role
ASD
- in children (age ~2-3 years): increased grey and white matter volume with particularly enlarged frontal lobes
- linked to enlarged amygdala
–> size of amydala is associated with severity of social symptoms
–> abnormal eye contact, recognising emotion in faces and empathy could be related to amygdala dysfunction
- associated with elevated levels of blood serotonin and abnormalities in the serotonin transporter protein
Autism and language
TD children: first words soon after first birthday
ASD children: first words on average at 3 years old
–> grammatical development at usual pace
- language abilities range from non-verbal to very fluent and articulate
- ASD primarily impacts pragmatic aspects of language
–> dominance of semantic (literal meaning) interpretation
What is Theory of Mind (ToM)?
= ability to make inferences about another person’s mental states and understand that someone else’s experiences, beliefs and desires differ from their own
Pragmatics and autism
- impaired ToM abilities
Sally-Anne task tests the ability to represent the belief-sates of others even when they are false
- TD children and children with Down’s syndrome typically make the right guess –> expect Sally to look for her marble in the place where she put it
- ASD children usually guess that Sally will look in the place where Anne put the marble (Sally cannot know, but children witnessed)
In conversation –> social norms (truthful, efficient, relevant): cooperative principle
- speakers often use conversational implicatures
–> ASD children more likely interpret content literally and are less likely to recognise conversational implicatures are valid responses
—> BUT those that are able to recognise them, are also able to pass the Sally-Anne task
Other langauge impairments in autism
- ASD also impacts sensory processing
–> TD children more sensitive to human speech compared to other sounds BUT ASD children often lack this bias - Syntax is not particularly impaired but some studies found restricted set of syntactic structures in children with ASD
- people with ASD have often difficulty with sponatenously producing speech and give delayed responses
- common symptom is echolalia = automatic repetition of another’s speech
–> may have pragmatic function: take a ‘turn’ without having to produce original speech
What is William syndrome?
= a genetic disorder characterised by severe intellectual impairment, but expceptional language skills
- caused by a deletion in Chromosome 7, band q11.23 –> including genes involved in neurotransmitter release
Characteristics of Williams Syndrome
Particularly impaired:
- spatial reasoning, mathematics, coordination
Particularly pronounced:
- highly expressive language, large vocabularies and exaggerated prosody
- extreme friendliness towards strangers, high empathy, musicial ability (common)
Distincitve facial features
- wide mouth, upturned noses, puffy cheeks, large eyes with a starburst pattern
- also causes cardiac issues and hypercalcemia
- reduced brain volume –> in particular occipital lobe is small
- enlarged superior temporal gyrus, amygdala and cerebellum
- greater neural response to spoken words than healthy controls (EEG)
What is schizophrenia?
= neurocognitive disorder characterised by abnormal brain activity and specific changes in neuronal oscillations
- also affects how the brain processes information, perception and emotions
Affected neurological areas:
- frontal lobe
- temporal lobe
- parietal lobe
- cerebellum
Pathological profile
- loss of reality
- delusions and hallucinations
- disturbances of self-experience
- formal thought disorder
- disorganised thinking
- affective disorders eg emotional flatness
- difficulties in processing contextual information
- psychomotor disorders and drive disorders
- language disorders
Schizophrenia: language disorders
- acoustic and phonological disorders
- syntactic simplifications/syntactic processing
- restricted semantic associations
- altered language dominance
- verbal hallucinations
- verbality and word production
- verbal flow
- pragmatic abilities
Schizophrenia: Oscillopathy
- neural oscillations are rhythmic fluctations in the brain’s electrical activity
- occur at various frequencies and are responsible for information processing (eg language processing)
Abnormal brain waves:
1) Theta waves (4-8Hz)
- often reduced, especially in occipital and frontal regions
–> indicated difficulties: information integration, memory retrieval
2) Alpha waves (8-12Hz)
- reduced in the left frontal lobe
–> indicated difficulties: inefficient processing, filtering out linguistic distractions
3) Beta waves (12-30Hz)
- reduced in the left frontal lobe
–> indicated difficulties: processing complex syntactic structures, eg embedded sentences
4) Gamma waves (30Hz an higher)
- reduced in frontal lobe during semantic taks + overconnectivity in other regions
–> indicated difficulties: semantic processing and inefficient information processing
Schizophrenia: genes and language
- many candidate genes in schizophrenia are overrepresented in gene sets considered important for langauge development
significant candidates
- ZNF804A
- FOXP2
- DISC1
- COMT
- NRG1
- GRM3
