cs&d 210 exam three - learning objectives

what are the 5 higher levels of brain function and what structures are generally associated with them?

parisylvian network for language, parietofrontal network for spatial cognition, occipitotemporal network for face and object recognition, limbic network for retentive memory, and prefrontal network for cognitive and behavioral control

language definition

symbolic representation of thoughts + spoken, written, signed

phonology definition

rules governing the ways in which the sounds of language are organized

morphology definition

rules governing how words are formed

semantics definition

rules governing the meaning of words and combinations

syntax definition

rules governing how words are combined to form sentences

pragmatics

rules governing the use of language in context

what is the categorical hemisphere and what does it do?

(usually) the left hemisphere specializes in sequential-analytic processes like language and analytic reasoning

what is the representational hemisphere and what does it do?

(usually) the right hemisphere specializes visuospatial relations like identification of objects by their form, recognition of faces, and recognition of muscial themes

what side of the brain is usually dominatn for language?

the left hemisphere

how does language dominance happen?

lateralization begins early in prenatal development and can be changed by brain damage, but it’s unclear how much is genetically preprogrammed vs. influenced by environmental factors

broca’s area functions of language

formation of words, ordering of words (syntax), and output for spoken language

wernicke’s area function of language

involved in spoken word comprehension + permits understanding of written and spoken language and enables a person to read a sentence, understand it, and say it out loud

arcuate fasciculus (conduction area) function of language

important for repeating and speaking a written word

exner’s area function of language

writing output pathway that translates and integrates linguistic and motor output commands + form written words and sentences

visual word form area function of language

acts as the brain’s “letterbox” for reading, rapidly identifying written letters and words regardless of font or case

angular gyrus function of language

perception of written language, as well as other language processing functions

insula function of language

relays somatosensory information and planning and coordinating speech/language and swallowing

aphasia definition

an impairment of language that affects production and/or comprehension and is due to injury to the brain

dysphagia definition

covers a wider range of issues regardless of their cause

alexia definition

impaired reading

agraphia definition

impaired writing

paraphasia definition

sounds or words are replaced by substitutions so that desired response is only approximated

literal/formal/phonological paraphasia definition

incorrect or incomplete phonemes (grass is g_een)

verbal paraphasia definition

incorrect words (grass is blue)

semantic paraphasia definition

the substitued word is related to the intended word

remote paraphasia definition

the substituted word is, at most, distantly related to the intended word

neologisms definition

nonsense words (grass is gronus)

what are the common causes of aphasia?

STROKE, traumatic brain injury, brain tumors, degenerative conditions, exposure to neurotoxic agents

what are the three parameters used to categorize aphasia in the ‘classic’ model?

fluency, comprehension, and repetition

broca’s aphasia

nonfluent/effortful, impaired repetition, relatively intact comprehension, due to occlusion of the superior division of the middle cerebral artery

wernicke’s aphasia

fluent but still paraphasic verbal output, impaired repetition, impaired comprehension, infarct to inferior division of middle cerebral artery, to the posterior temporal or angular branches

conduction aphasia

fluent, impaired repetition, intact comprehension, lesion is usually left arcuate fasciculus, superior temporal regions, or supramarginal gyrus

global aphasia

nonfluent/mute initially, impaired repetition, impaired comprehension, large MCA lesion (frontal-temporal-parietal lesion)

transcortical motor aphasia

nonfluent, intact repetition, intact comprehension, ‘anterior watershed zone’

mixed transcortical aphasia

nonfluent/dysarthric, intact repetition, severly impaired comprehension, ‘isolation syndrome’ = pathological function of language network when it is isolated from other regions of the brain

transcortical sensory aphasia

fluent, intact repetition, impaired comprehension, lesion to the left posterior temporal-occipital lobe (‘posterior watershed zone’)

anomic aphasia

fluent/word finding pauses, intact repetition, relatively preserved comprehension, focal lesion to temporal or parietal lobe

what are some problems with the classic model?

it’s oversimplified and some patients don’t ‘fit’ classic models and neuroimaging also shows that sometimes syndromes don’t map well onto lesions

what is the dual-stream model?

divides cortical processing into two pathways

ventral stream role

“what” stream for perception and identification

dorsal stream role

“where” stream for spatial awareness, action, and sensorimotor integration

alexia WITH agraphia

lesion in the left interior parietal lobule and overlaps with wernicke’s aphasia and evolves during recovery

alexia WITHOUT agraphia

lesion in the left PCA territory, often accompanied by visual field deficit and inability to name colors, patient can write, but not read what they have written

what are the two subcortical aphasias?

anterior subcortial aphasia and thalamic aphasia

anterior subcortical aphasia

head of caudate, anterior putamen (basal ganglia), anterior limb internal capsule and non-fluent (with dysarthria), mild deficits with naming and auditory comprehension

thalamic aphasia

typically damage to dominant thalamus and fluent with paraphasic errors, intact comprehension

progressive aphasia

due to neurodegenerative processes and causes word finding and naming issues, many variants depending on language modalities that are impaired, patterns are slightly different than ‘classic’ aphasias

dysarthria definition

deficit in control or execution of speech movements

apraxia of speech definition

deficit in planning or programming speech movements

flaccid dysarthria site of lesion and neuromotor basis

LMN and weakness

spastic dysarthria site of lesion and neuromotor basis

bilateral UMN and spasticity

ataxic dysarthria site of lesion and neuromotor basis

cerebellum and incoordination

hypokinetic dysarthria site of lesion and neuromotor basis

basal ganglia circuit and rigidity/reduced ROM

hyperkinetic dysarthria site of lesion and neuromotor basis

basal ganglia circuit and involuntary movements

UUMN dysarthria site of lesion and neuromotor basis

unilateral UMN and weakness/incoordination

mixed dysarthria site of lesion and neuromotor basis

combination and combination

apraxia of speech site of lesion and neuromotor basis

left (dominant) hemisphere and motor programming

flaccid dysarthria symptoms

reduced ability to move – small, weak movements (paralysis vs. paresis), hypotonia, diminished reflexes, atrophy, fasciculation, fibrillations, fatigue (rapid weakening followed by recovery)

spastic dysarthria symptoms

resistance to passive stretch, weakness, loss of skilled movements, increased tone, increased reflexes, dysphagia, drooling, facial expression reduced, pathological laughing and crying

ataxic dysarthria symptoms

errors of force, speed, timing, and range of movements translate into difficulty with coordination of movement, dysprosody, irregular articulation errors, stumbling over words, prolonged phonemes

hypokinetic dysarthria symptoms

decreased mobility or range of movement, indistinct articulation and difficulty initiating movements, reduced pitch and loudness, lack of emotional prosody, faster and increasing speech rate, rigidity ‘cogwheel,’ bradykinesia (slow), akineasia (lack of involuntary movement), loss of postural reflexes

hyperkinetic dysarthria symptoms

abnormal, rhythmic, or irregular and unpredictable (rapid or slow) involuntary movements, extra involuntary movements of all speech subsystems of speech, uncontrolled variable rate and volume, excess loudness variation, sudden forced inspiration/expiration, transient breathiness

UUMN dysarthria symptoms

symptoms and perceptual characteristics are not well defined, contralateral impairments of fine, skilled movements, atypical/increased reflexes

mixed dysarthria symptoms

any combination of 2+ dysarthria types due to neurologic disease distributed across 2+ dimensions of the nervous system

apraxia of speech symptoms

impaired capacity to plan and/or program sensorimotor commands for the positioning and movement of speech muscles, effortful trial-and-error groping with attempts at self correction, frequent and variable articulatory errors that increase with complexity of speech targets, automatic and reactive speech is better than volitional speech

how do we assess and categorize motor speech disorders?

age and type onset, course, or progression; site and severity of damage or lesion; perceptual, acoustic, or physiologic characteristics; and speech production tasks

chiari malformation

displacement of cerebellum through foramen magnum

bell’s palsy

disease of CN VII, unilateral, sudden onset and temporary, viral/autoimmune/viral/allergic response

what are the phrenic nerves and what do they control?

nerves involved in respiration are spread from the cervical through thoracic divisions of the spinal cord + injuries above C3 can result in respiratory paralysis

how does a lesion in the final common pathway (lower motorneuron) lead to flaccid dysarthria

cuts off the direct nerve impulses from the brainstem/spinal cord to the speech muscles, leading to failure of muscle contraction + this damage disrupts the final motor units, resulting in profound muscular weakness, loss of muscle tone (flaccidity), and reduced speed, range, and accuracy of articulatory movements

what is the pattern of lesion associated with UUMN dysarthria?

unilateral, focal injury within the upper motor neuron system (redundancy assures everything is not ‘wiped out’)

corticobulbar pathway

motor cortex, through internal capsule, pes pedunculi, cross the midline in the brainstem, synapse on LMN

corticospinal pathway

similar path but cross in the pyramids of the medulla

what patterns result from a lesion to the UMN systems?

UMN lesions cause weakness (paresis), spasticity, and hyperreflexia from a loss in inhibitory control over reflex arcs

ataxia definition

a neurological lack of muscle coordination and control caused by damage to the brain (usually the cerebellum), nerves, or spinal cord

how does the cerebelum modulate speech movement and why does damage to a cerebellar hemisphere affects the ipsilateral side of the body?

the cerebellum modulates speech by acting as a predictive, feedforward controller that refines the timing, force, and sequencing of muscular movements to produce fluid, rapid articulation + it corrects errors between intended and actual movement, preventing slurred or jerky speech (dysarthria) + damage causes ipsilateral effects because the cerebellum receives input and sends output to the same side of the body via double-crossing pathways (first crossing down from the motor cortex, then crossing back within the cerebellar tracts)

what are the major conditions/diseases that lead to ataxic dysarthria?

spinocerebellar ataxia, multiple sclerosis, vascular disorder, and tumors

what are non-speech/associated signs of cerebellar damage?

hypotonia, slow voluntary movements, jerky movements, wide-based gait, impairments of equilibrium, intention tremor, terminal tremor, truncal titubation, dysmetria

what are the major speech characteristics that define ataxic dysarthria?

incoordination of speech movements, leading to a "drunken," slurred, or irregular speech pattern + the core deficit is in the timing, force, and range of movement

what are the major inputs and outputs of basal ganglia?

major inputs come from the cortex and substantia nigra to the striatum, while outputs, largely inhibitory, project from the internal pallidum (GPi) and substantia nigra pars reticulata (SNr) to the thalamus

what are the major features of parkinson’s disease?

hypokinesia, postural instability, tremor, rigidity, bradykinesia, sensory impairment, dysarthria, dysphagia, cognitive deficits, depression, gait disturbances

what are non-speech findings associated with hypokinetic dysarthria?

face (unblinking, unsmiling, masked, expressionless at rest, lack of animation), swallow infrequently and drooling, dysphagia in 40-80%

dyskinesia defintion

abnormal, involuntary movements, regardless of etiology

dystonia definition

slow hyperkinesia characterized by involuntary abnormal postures resulting from excessive co-contraction of antagonistic muscles

hyperkinesia definition

excessive, bigger movement

hypokinesia definition

small movement

akinesia definition

inner sense of restlessness but lack of movement/freezing, difficulty initiating movement

chorea definition

‘dance’-like purposeless, unpredictable movement

athetosis definition

inability to maintain a body part in a single position because of superimposed slow, writhing, purposeless movements that tend to flow into one another

ballism definition

gross, abrupt contractions of axial/proximal muscles of extremities that produce flailing

tremor definition

regular, rhythmic (4-7 Hz), periodic movement of a body part

tic definition

involuntary complex movements; rapid, stereotyped coordinated or patterned movements that are under partial voluntary control

myoclonus definition

involuntary single or repetitive brief jerks of a body part (rhythmic or non-rhythmic)

spasm defintion

general term that designates a variety of muscle contractions

what are the major presenting/distinguishing signs of hyperkinetic dysarthria?

abnormal, rhythmic, or irregular and unpredictable (rapid or slow) involuntary movements, extra involuntary movements of all speech subsystems of speech, uncontrolled and variable rate and volume, excess loudness variation, sudden forced inspiration/experation, transient breathiness

what type of damage generally causes hyperkinetic dysarthria?

damage to the basal ganglia control circuit in the brain

huntington’s disease

characterized by chorea, dementia + constant jerky movements, including facial movements, restless/fidgety hands

tardive dyskinesia

involuntary, repetitive movements—such as lip smacking, eye blinking, and tongue protrusion—caused by long-term use of dopamine-blocking medications

oromandibular dystonia

involuntary, forceful muscle spasms in the face, jaw, and tongue, causing difficulties with chewing, swallowing, and speaking