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Neurogenic lang disorders, functions affected
Affects one or more modalities of lang (understanding spoken lang, understanding written lang, producing spoken lang, producing written lang). Can also affect related skills that are dependent on symbolic manipulation (comm. gestures, mental calculation)
evidence that lang is based in left hemisphere
Both right & left handed people are left hemisphere dominant for lang
- Primary auditory cortex: info about sound is analyzed here & transmitted to wernicke’s area
- Wernicke’s area: analyzes sound info to determine the word that was said
- Arcuate fasciculus: info from wernicke’s is transmitted thru here to broca’s
- Primary visual cortex: analyzes the image & transmits the info about image to angular gyrus
- Angular gyrus: decodes the image info to recognize the word & associate this visual form with the spoken form in wernicke’s
- Broca’s area: info about word is transmitted here from arcuate fasciculus.
- Primary motor cortex
main parameters assessed in a lang assessment & how they are applied
- Fluency: responses to conversational speech (ask open ended questions). Expository speech (describe everything going on in a complex picture).
- Comprehension: identifying objects, shapes, letter (word discrimination.) Following commands (point to ceiling). Story comprehension (answer questions about a story). Not an all or none phenomenon (more likely to miss difficult items). Make sure non-response is not due to another problem (apraxia)
- Repetition: involves exact repetition of what the examiner says. Start simple & progress to more complex phrases.
categorization of aphasia
- Global: nonfluent, no comprehension, no repetition. Severe deficit across all lang modalities.
- Broca’s: nonfluent, comprehension, repetition. Telegraphic speech, content words, agrammatism, good comprehension.
- Wernicke’s: fluent, no comprehension, no repetition. Jargon, neologistic, freq paraphasias.
- Conduction: fluent, comprehension, no repetition
- Anomic: fluent, comprehension, repetition. Word finding problems.
- Transcortical motor: nonfluent, comprehension, repetition.
- Transcortical sensory: fluent, no comprehension, repetition
- Fluent: speech output approximates normal speech in terms of- rate fo word production, length of each utterance produced w/o notable pause, melodic contour of utterances, overall ease of the speaking act; lesions posterior to rolandic fissure
- Nonfluent: speech output is the opposite- slow rate, short utterances, effortful production; lesions anterior to rolandic fissure.
other lang disorders & neurological areas involved
- Alexia: reading- word recognition, reading sentences, word-picture matching. Inability or decreased ability to understand written lang due to brain injury (angular gyrus)
- Agraphia: writing- confrontation naming (written response), sentences to dictation, narrative writing. Inability or decreased ability to produce written lang due to brain injury (supramarginal gyrus)
- Acalculia: word finding/naming- confrontation naming (oral response), requires free recall response (may be followed up with phonemic cue or fill in the blank; testing recognition of name tests comprehension) Calculation abilities (angular gyrus, frontal lobe)
terms describing symptoms
- Agrammatism- omission of function words (drove store. Shop. Wife, find spam. Good have supper. Nap. Great cook.)
- Paraphasia- unintended words. ( I took the train, cab, bus)
- Neologism- new words/ nonsense words
- Echolalia- repetition of words
types & aspects of attention
- Controlled attention (effortful processing): activity of purposefully directing attention (focusing on text on a page during reading)
- Automatic attention: non-volitional direction of attention due to properties of stimulus (reflexively attending to a sudden loud noise, semantic priming)
- Vigilance: alertness or readiness to respond to occurrence of events or stimuli
- Sustained (concentration): maintaining attention to a task over time
- Selective (focused): attention to one task over another
- Divided: attention to 2 or more tasks at the same time
- Shifting attention: disengaging attention from one stimulus & engaging attention toward a diff stimulus
Parietal cortex- unilateral lesions to inferior parietal lobule associated with neglect of (inattention to) exprapersonal space on contralateral side
- 3-5% more often in males
- involves 3 main types of symptoms (inattention, hyperactivity, impulsive behavior).
- May be multiple comorbid symptoms ( depression, sleep disturbance, conduct disorder)
- Involves changes in dorsolateral prefrontal cortex (executive functioning)
types of memory
- Procedural (implicit): knowing how to do things. Established thru the repetition of activity.
- Declarative (explicit): knowing what, episodic (memory for specific events) autobiographical in nature; involves temporal or spatial aspects (when & were it occurred), semantic (general knowledge
- Major brain areas involved
- Recognize the 3 processes & 3 stages involved in episodic memory (encoding, storage, retrieval)
anterograde vs retrograde amnesia
- Anterograde amnesia: inability to form new memories; memory for events prior to onset of illness may be preserved; many causes (alcohol, accidents, infection, surgery)
- Retrograde amnesia: inability to recall events which occurred before the onset of illness; may extend backwards for seconds, minutes, hrs, days, months, years; ability to form new memories may be intact.
Case of H.M.
Neurosurgery for intractable seizure disorder (epilepsy). No evidence of memory disorder prior to surgery. Brain tissue thought to be the source or locus of seizure activity removed. Anterograde (loss of ability to store new declarative memories); retrograde for 1-2 yrs prior to surgery; working memory intact; implicit memory intact. Hippocampus & related structures are responsible for consolidation of new declarative memory into long term storage; working memory & procedural memory are subserved by other brain structures.
- Volition: intention/initiation; awareness of one’s self
- Planning: conceptualize change from the present (look ahead); view environment objectively (take the abstract attitude); think of alternatives, weigh & make choices; control impulses, inhibition; sustained attention.
- Purposive action: initiate, maintain, switch, stop, sequences of complex behavior in an orderly & integrated manner
- Effective performance: monitor; self correct; regulate the intensity, tempo, & other qualitative aspects of delivery; notice & correct or compensate for errors.
cases of phineas gage
Damage to left frontal lobe. Alerf after accident, but developed infection & lapsed into 2 week coma. Prior to accident, hard working, responsible, well liked. After accident, irresponsible, unpredictable, profane.
types of stroke
- Ischemic (thrombo-embolic): blood vessel is blocked. Brain tissue is starved of oxygen. Tissue damage occurs quickly. Initial damage provokes a cascade of processes that cause further damage (release of free radicals)
- Hemorrahic: blood vessel breaks open & blood enters brain tissue. Brain tissue is damaged at site due to pressure from increasing volume of blood. Tissue also damaged due to toxic effect of blood on neural tissue (imbalance of ions). Loss of blood site may also reduce blood supply elsewhere (causing ischemic damage). Tissue is also damaged distally due to increased pressure.
- Risk factors: medical- high blood pressure, elevated cholesterol, diabetes, obesity, heart disease. Behavioral- smoking, alcohol, inactivity. Heredity- family history; age/sex (1/4 under 65, males > females but women are more likely to die); race/ethnicity (asian & non-hispanic whites have lowest risk)
- Warning signs: sudden numbness or weakness of face, arm or leg, especially one sided; suddent confusion, trouble speaking or understanding; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, loss of balance or coordination; sudden severe headache with no known cause.
- Survival: 10% complete recovery; 25% minor impairment; 40% moderate-severe impairment; 10% require nursing care; 15% die acutely. Within 1 year- 23% die, 14% have another stroke. Subarachnoid hemorrhage (7% of all strokes)- 50% die, 25% suffer permanent disability.
traumatic brain injury
- Causes/epidemiology: an insult to the brain from external force. Not of a degenerative or congenital nature. May reduce diminished or altered state of consciousness. Results in impairments of cognitive abilities or physical functioning. Can result in disturbances of behavioral or emotional functioning & lang disorders.
- Closed head- blow to the head in which skull is not penetrated. Damage- coup/contracoup: site of blow bruising, site directly opposite to where blow was struck. Shearing: brain tissue alternatively compressed & stretched; tearing of brain tissue. Contusion & bleeding from impact. Intracranial hemorrhage at impact site.
- Penetrating head- external object (bullet) penetrates the skull & dura mater.
- Acute symptoms: common (concussion)- headache, dizziness, nausea, slurred speech, vomiting. Severe- loss of consciousness, coma, seizures, death.
- secondary symptoms: personality changes, depression, cognitive disability (memory & attention), anxiety, decreased self esteem
- Not a specific disease, but a term for a cluster of symptoms that may be caused by numerous diseases/conditions. Acquired persistent intellectual impairment involving at least 2 of the following- lang, memory, visuospatial skills, emotion/personality, cognition/executive functions.
- Causes: non-reversible: alzheimer’s, vascular dementia, lewy body disease, parkinson’s disease, pick’s disease, Huntington’s disease, HIV. Reversible- brain tumor, nutritional/metabolic disorders/conditions, vitamin B12 deficiency, normal pressure hydrocephalus, medication/drug effects.
- Characteristics of alzheimer’s disease: initial: forgetfulness, misplacing items, occasional confusion, difficulty with getting lost, difficulty with completing complex tasks, depression, decreased social skill. Later: obvious memory loss, difficulty reading/writing, poor judgment, hallucination/delusions, difficulty with ADLs, inappropriate/erratic/violent behavior, withdrawal.
- Rostral: towards head/forward
- Caudal- towards tail
- Dorsal/posterior- towards back
- Ventral/anterior- towards stomach/ on front
- Lateral- towards outside
- Medial- towards inside
- Superior/cranial- on top
- Inferior- lower side
- Ipsilateral- same side
- Contralateral- opposite side
- Bilateral- both sides
- Frontal lobes (inc. organization of the homunculus): most anterior section of cerebrum. Inferior boundary (lateral sulcus/ sylvian fissure) posterior boundary (central sulcus/ rolandic fissure) functions: voluntary motor movement. Expressive speech. Executive functions in prefrontal cortex (planning, logic, impulse control) Primary motor cortex- motor strip initiates voluntary movement. Supplementary motor cortex involved in motor learning & planning & coordinating sequential or complex movements. Frontal eye fields control movement of eyes. Homunculus is an image that shows the relative amount of cerebral cortex surface area given over to processing the diff sensory inputs & motor outputs of human nervous system. Broca’s area is responsible for expressive speech.
- Parietal lobes: anterior is central sulcus, inerior is lateral sulcus (extended), posterior is fuzzy with occipital lobe. Functions: perception of somatic sensation in primary somatosensory strip- postcentral gyrus, the primary cortical area for sensory input from contralateral side of body, depicted with homunculus. Sensory strip (phantom limb)- cortical organization of an individual who has had a limp amputated still includes the amputated limp; there can still be a perception of that limp because it is still represented in brain tissue. Interpretation, integration & elaboration of sensory experience- spatial orientation, selective attention, complex perceptual skill, cross-modality integration, memory & cognition. Reading, writing, word finding, calculation (supramarginal gyrus & angular gyrus)
- Temporal lobes: superior (lateral sulcus) & posterior (occipital lobe). Functions: superior temporal gyrus heschl’s gyrus is primary auditory cortex; posterior portion- wernicke’s area for receptive language. Medial surface- primary area for olfaction.
- Occipital lobes: smallest lobe. Primary visual cortex. Visual association cortex- important for object recognition, reading, visual memory. Perisylvian zone- major cortical areas & connections for lang processing. Arcuate fasciculus- association pathway of left hemisphere, connects wernicke’s & broca’s areas.
- Corona radiata: cerebral connection to lower NS. Deep cerebral white matter, contains both ascending & descending axons that carry nearly all of the neural traffic to & from the cerebral cortex.
- internal capsule: layer of white matter formed from converging fibers of corona radiata. A huge fiber tract linking the thalamus & cerebral cortex. Divided into 5 portions.
- Corpus collosum: commussural pathway. Major connection b/w LH & RH (crosses longitudinal fissure). Anterior commissure- connects L & R olfactory bulbs, amygdala, medial/inferior temporal lobes. Posterior commissure- connects L & R occipital lobe
- Basal ganglia: caudate nucleus, putamen, globus palldus. Regulates/modulates motor function. (Putamen, Globus Pallidus, Caudate): gray matter located deep within brain. Very important in motor control. Plays a role in learning, cognition, emotions. Implicated in parkinson’s disease & huntington’s chorea.
- Peri-sylvian zone
- Sulci: groove or valley; Gyri: elevation or ridge.
- somatosensory; 4, 6: motor; 8: frontal eye fields; 17: vision; 22: wernicke’s; 28: cognition; 39: visual-parietal; 41, 42: audition; 44, 45: Broca’s
Limbic System (CNS)
(Hippocampus, Amygdala, Septum, Fornix, Mammillary bodies, limbic lobe): responsible for emotion-instinctive-visceral functions rather than higher order functions (lang, thinking). Amygdala- almond shaped. Very important for emotional functioning. Fornix- arching band of nerve fibers that connects the hippocampus to mammillary bodies of hypothalamus & forms an arch over thalamus. Hippocampus- consolidation of new memories (coverting short term memory to more permanent memory). Recalling spatial relationships in world around us.
thalamus, hypothalamus. Relay station (thalamus), regulates basic drives such as hunger, thirst & temp control.
superior colliculus (visual & visual reflexes); inferior colliculus (hearing & auditory reflexes). Cerebral peduncles- white matter fiber tracts descending from cortex thru midbrain (corticospinal tracts)
continuation of tegmentum from medulla to midbrain. Bridges to & from cerebellum contain many fibers called cerebellar peduncles.
“the bulb” has ridges that contain ascending & descending tracts. Lateral bulge called olive- the major nucleus in medulla. Ventral ridges (pyramids) contain corticospinal tract, a major descending motor tract (pyramidal tract)
cerebellar cortex made of gray matter; internal white matter called arbor vitae. 2 cerebellar hemispheres. Smooth coordination of muscle activity; sequential, complex movements; balance/vestibular system functions; postural stability & fixation; new motor learning
Spinal Cord (CNS)
ascending & descending communication w/ rest of body. Landmarks (beginning, ending, segments): continuation of brainstem. Begins at foramen magnum where CNS leaves skull. Terminates at conus medullaris at level of 1st or 2nd lumbar vertebrae. Other nerves trail down (cauda equina- descending peripheral nerves) Reflex arc: sensation travels up spinal nerve to spinal cord. Within spinal cord, connects via intercalated neuron to outgoing (motor) neuron. Motor nerve travels back out to limb & creates movement
Primary Cortical Areas & Cortical association areas
- Primary cortical areas: the frst cortical processing point for incoming sensory info and the last cortical processing point for outgoing motor info. Somatosensory cortex (parietal lobe). Auditory cortex (heschl’s gyrus temporal lobe). Viual cortex (along calcarine fissure in occipital lobe). Olfactory cortex (medial aspect of temporal lobe)
- Unimodal: lowest level of processing. 1 type of info is being processed. Either motor or sensory input. Adjacent to primary sensory area.
- Polymodal: more than 1 info is being processed. In area between primary reception cortex for each modality. Matches present sensory input with past sensory info.
- Supramodal: highest level. Neural processing- not directly linked with sensory or motor functions. Found primarily in prefrontal area.
- Spinal nerves & connections to spinal cord
- Ventra/motor/efferent: connected to muscles at myoneural junction & stimulate contraction.
- Dorsal/sensory/afferent: carries info for a particular section of skin called dermatome/myotomes
meninges & associated structures
- Dura mater (tough mother)- most external covering just beneath skull. 2 layers- outer layer follows & is attached to skull; inner layer protrudes into long fissure b/w cerebral hemispheres (falx cerebri) & into space b/w cerebrum & the cerebellum (forming tentorium cerebelli) gaps where 2 layers separate are called venous sinuses.
- Arachnoid (spider) mater- web-like middle covering. Outer membrane adheres to inner surface of dura mater.
- Pia mater (pious mother)- thin, adheres to surface of brain & spinal cord.
CSF major functions & path of flow
- entire surface of central nervous system is bathed by a clear colorless fluid (CSF). Produced by choroid plexus. Functions: buffering, buoyancy, excretion of waste products, endocrine median for brain
- Lateral ventricle: one in each hemisphere; connects to 3rd ventricle thru foramen of monro.
- Third ventricle: located b/w the 2 thalami. Connects to cerebral aqueduct in midbrain.
- Fourth ventricle: located b/w pons & cerebellum. Connects to central canal of spinal cord.
Major arteries supplying brain
- External carotid artery (ECA)- facial muscles; oral, nasal, orbital cavities.
- Internal carotid artery (ICA)- joins circle of willis; branches into anterior & middle cerebral arteries
- Vertebral arteries arise from subclavian artery; join to form basilar artery
- Circle of willis- equalizes blood flow b/w the 2 hemispheres; allows blood to continue to flow to all areas even if one vessel is blocked.
- Dural sinuses- sup. & inferior sagittal sinuses; straight sinus; transverse sinuses; sigmoid sinus.
anterior, middle, posterior
parts of neuron
- Cell body: genetic & metabolic center of neuron. Contains nucleus & cytoplasm or cytosol
- Dendrites: branches of neurons, extending from cell body. Receive incoming info from receptors & other neurons. Act as resistors from one another.
- axon: fiber that conducts nerve impulses away from cell body toward other parts of nervous system, glands, or muscles. Axon hillock- area where axon exits the cell body; transmission of outgoing signals start here.
- Myelin: composed of lipids. Surrounds portion of axon. Formed by oligodendrocytes in CNS, formed by Schwann cells in PNS. Nerve impulse jumps from node to node which increases speed of action potential conduction.
- Telodendrion: branches that axons divide into. At the end there is a swelling called terminal bouton which contains synaptic vissicles.
- Synapse (synaptic junction): communication b/w neurons occurs from axon terminal of transmitting neuron to receptive region of receiving neuron.
- Occur when a neuron is stimulated- the stimulation causes ion channels to open or close near the area of stimulation. This results in local changes in membrane potential. Changes can make the cytosol either less negatively charged or more negatively charged than area outside of membrane. Most often occur at dendrites of neuron.
- Excitatory local GP: decreased negative charge inside cell depolarization
- Inhibitory local GP: increased negative charge inside cell hyperpolarization.
- Occur when excitatory GP cause the membrane potential at the axon hillock to depolarize enough to reach a critical level (threshold). Triggers a wave that moves w/o decrement all the way to end of axon. For any given cell. The action potential always occurs in the same way every time. Info is encoded in freq of action potentials (not magnitude or duration)
- Sequence of events: prior to AP- passive K channels open, voltage-gated channels are closed, Na-K pump maintains ion concentrations, resting potential is -70mV. Stimulation of dendrites results in local graded potentials (inhibitory or excitatory). If cell membrane is sufficiently depolarized by excitatory potentials, the critical threshold is reached (-55mV). When threshold is reached- nearby voltage-gated Na channels open allowing Na ions to rush into cell; voltage potential inside cell rises dramatically (become less negative); this depolarization causes additional adjacent voltage-gated Na channels to open & this continues to spread across cell membrane; voltage potential inside cell continues to rise up to +40mV. When +40 is reached- voltage-gated Na channels close; voltage gated K channels open allowing K ions rush out of cell; voltage potential inside cell goes back down (repolarizes). The voltage-gated Na channels cannot re-open for about a millisecond- additional action potentials cannot occur (absolute refactory period); insures AP can only travel in 1 direction. The K gated channels stay open, hyperpolarizing the cell membrane- relative refactory period; AP can again be generated but a stronger excitatory GP is required to reach threshold. Battery is charged by Na-K pump that helps maintain the balance of ions in extracellular & inreacellular fluid of cell. If pumos 2 Na out for every 2 K pumped in.
- Synaptic cleft: space between end of 1 axon & beginning of the next neuron.
- When AP gets to the end: AP reaches axon terminals. AP triggers voltage-gated Ca channels to open. Ca ions cause synaptic vesicles to move to pre-synaptic membrane & open & releasing neurotransmitter into synaptic cleft. Neurotransmitter diffuses across synaptic cleft & binds to a receptor on the postsynaptic membrane. Neurotransmitters stimulate post-synaptic membrane which causes ion channels to open. Neurotransmitters can affect postsynaptic membrane in 2 ways (EPSP or IPSP). EPSPs & IPSPs are graded responses that reflect the nature & magnitude of neurotransmitters released at synapse at any given point in time. After IPSP or EPSP is generated the neurotransmitter can be released back into synaptic cleft. Neurotransmitters in synaptic cleft can then- be taken back up into vesicles in presynatpic membrane (reuptake), be destroyed, or diffuse out.
- Acetycholine: motor control, sleep-wake cycles, & memory. Anything related to this may be described as cholinergic. Disorders- myasthenia gravis, alzheimer’s disease.
- Dopamine: motor control, attention, learning, addictive behaviors and/or pleasure. Disorderse- parkinson’s disease, schizophrenia.
- Norepinephrine: sleep, attention, vigilance. Depression
- Serotonin: sleep/wake cycle, depression, eating, pain regulation. Depression
- Gaba: brief inhibitory synaptic event. Huntington’s chorea.
general sensory vs special sensory systems
- Somatosensory- pain, temp, touch, proprioception
- Special- vision, hearing, taste, smell, balance
typical somatosensory systems organization
- 1st order- transmits info from extremity (receptor) to CNS
- 2nd order- axon crosses midline & travels to contralateral thalamus
- 3rd order- travels from thalamus to ipsilateral somatosensory cortex
2 major somatosensory systems
- Anterolateral system (anterior & lateral spinothalamic): lateral spinothalamic (pain, temp); anterior spinothalamic (diffuse, light touch) [no 3rd order]
- Dorsal column-medial lemniscal system: fine touch (2pt discrim), pressure, proprioception; fasciculus gracilis (lower body), fasciculuc cuneatus (upper body [contralateral]
- Smell: olfactory. Transducers: bipolar cells in epithelial lining; peripheral process has chemoreceptors. Pathway: no 3rd order, no decussation, ipsilateral
- Vision: receptors- rods & cones. Optic. Pathway: 2nd order (ganglion cell) neurons form optic nerve. For vision, know how visual fields relate to pathway & the effect of lesions at various points in pathways.
- Auditory: receptor- ear. Vestibucochlear. For auditory, understand the issues associated w/ processing of auditory features throughout the system (freq, amp, on/offset)
corticospinal & corticonuclear tract
- Corticospinal tract: bilateral primary motor corticles (add input from motor association cortex & primary somatosensory cortex). Corona radiata. Internal capsule, cerebral penducle of midbrain. Pons. Medulla (decussation of pyramids- 85-90% of fibers cross over to other side) central horn motor nuclei of spinal nerve.
- Corticonuclear tract: innervate cranial motor nerves (voluntary pathways for movement of all speech muscles except for respiration.) begins at bilateral cortical motor cortices & terminates at motor nuclei of cranial nerves in brainstem. Most bilateral innervation- diaphragm, ocular muscles, upper face, jaw, pharynx, muscles of larynx. Intermediate amount- tongue. Most unilateral innervation- lower face & trapezius.
UMN & LMN
- UMN- neurons traveling from motor cortices to ventral horn motor nuclei in spinal cord/nerves or cranial nerve motor nuclei in brainstem/cranial nerves; 1st order neuron; synapses with lower motor neuron in motor nuclei.
- LMN (final common pathway)- connect cranial nerve motor nuclei in brainstem/cranial or ventral horn motor nuclei in spinal cord/nerves to muscle fibers; 2nd order neuron; receive input from many pathway in add to UMN.
- Olfactory I (sensory)- smell; olfactory bulb
- Optic II (sensory)- vision; optic tract
- Oculomotor III (motor)- eye movement; midbrain
- Trochlear IV (motor)- eye movement; midbrain
- Trigeminal V (both)- facial, controls jaw movement & chewing; pons [ophthalmic nerve, maxillary nerve, mandibular nerve]
- Abducens VI (motor)- eye movement; pons
- Facial VII (both)- taste, facial expressions; pons
- Vestibulocochlear VIII (sensory)- balance, hearing; pons
- Glossopharyngeal IX (both)- taste, swallowing; medulla
- Vagus X (both)- swallowing; medulla
- Accessory XI (motor)- neck muscles; medulla
- Hypoglossal XII (motor)- tongue movement; medulla
- Names: Oh Once One Takes The Anatomy Final, A Good Vacation So Heavenly
- Sensory/motor/both: Some Say Marry Money, But My Brother Says Bad Business Marry Money.
cranial nerves association
- Speech: trigeminal, hypoglossal
- Taste: facial, glossopharyngeal
- Swallowing: glossopharyngeal, vagus
- Sensation in head area
motor speech disorders
Disturbance of the speech production system of neurologic origin that results in being imperfectly understood or creating the impression that speech is bizarre or unusual (not a disorder of speech perception or a disorder of lang processing). Usual result is impaired production of speech segments (discrete sounds) & suprasegments (rate, stress, intonation). Can co-exist with other cognitive disturbances (aphasia). Caused by the same neuropathologies as other neurogenic disorders (stroke, disease, accidents, poisons, tumors).
Inability to perform a learned motor skill in the absence of paralysis. Muscle tone, strength, range of movement (ROM) are all normal. Characterized by loss of ability to voluntarily execute learned purposeful movements despite having the desire & the physical ability to perform. Not caused by incoordination, sensory loss, or failure to comprehend commands. Considered to be a disorder of motor planning.
apraxia of speech
Clinical signs- groping, inconsistent errors, increasing errors with length & complexity of utterance, patient aware of deficit, normal muscle tone, strength, range of movement. Neurological areas involved- premotor area, supplementary motor area, insular lobe.
Inability to speak because of a lack of coordination, spasticity, or weakness of the muscles of speech. Muscle tone is impaired (hypo/hypertonia), strength & ROM are reduced. Components of neural motor system- UMN, LMN, basal ganglia, cerebellum.
spastic dysarthria (UMN)
lesion results in increased tone & resistance to movement (hypertonia, spastic paralysis, hyperreflexia, clonus, babinski sign. Spastic- unilateral UMN damage- produces symptoms similar to bilateral, but less severe & temporary, cased by stroke or tumor; bilateral UMN damage- pyramidal (corticobulbar) & extrapyramidal pathways (from cortex to brainstem/spinal cord) run close to one another & both are damaged, caused by wide variety of neuropathologies. General characteristics- hypertonia (increased muscle tone, but weak muscles), hyperreflexia (stretch reflexes), limited range of motion, slowed rate of movement. Speech characteristics- harsh, monolound, monopitch, hypernasal w/o emission, imprecise artic.
flaccid dysarthria (LMN)
damage may be caused by infections, tumors, trauma, stroke, myasthenia gravis. Lesion in cranial/spinal nerve, ant horn of spinal cord, or cranila nerve axons in brainstem (hypotonia, flaccid paralysis, atrophy, fibrillations & fasciculations, hypo/areflexia. General characteristics- hypotonicity, hyporeflexia, weak muscles/muscle atrophy, fasciculations (tiny spontaneous muscle contractions). Speech characteristics- breathy, audible inhalation, hypernasal w/nasal emission, imprecise artic w/plosives & fricatives.
hypokinetic dysarthria (basal ganglia)
parkinson’s disease. Symptoms- tremor, rigidity, bradykinesia, masked fascies. Speech aracteristics- monopitch/loudness, decreased intensity, inconsistent rate (rushes of speech, inappropriate silence, repetition)
hyperkinetic dysarthria (Caudate & Putamen)
huntington’s disease. Symptoms- rapid, jerky involuntary movements. Speech characteristics- tremor, variable loudness, involuntary phonation, irregular artic, prosodic breaks, variable rate.
associated with cerebelar involvement. Lack of coordination. Fluctuations in phonation, loudness, pitch, & resonance. Imprecise artic including vowel distortions. Poor coordination of breathing with speech.
mixed dysarthria (multiple levels)
both UMN & LMN damage. Mixed signs of both spastic & flaccid.
5 dimensions of speech quality
- phonation- related to oscillation of vocal folds within the larynx. Caused by passage of air from lungs thru glottis. Related to voice quality, pitch & loudness.
- Resonance- related to size & shape of oral-pharyngeal cavity, influenced by closed of velopharyngeal gap. Reflected in nasality of speech
- Artic- determined by juxtaposition & movement of jaw, tongue, & lips
- Prosody- rate, rhythm, intonation of speech. Suprasement aspects of speech
- Respiration- inhalation & expiration of air. Powered by movement of muscles affecting shape of lung cavity. Limited by glottal opening.