Acquired comm. disorder that impaired a person’s ability to process lang, but does not affect intelligence. Impairs the ability to speak & understand others, & most people experience difficulty reading & writing.
5 phase model of outcomes research
1. Determine if treatment is safe
2. Treatment outcome
3. Efficacy (can the treatment work controlled setting)
4. Effectiveness (does treatment work-real world)
levels of evidence
I- randomized controlled
II- quasi experiments
III- non experimental study (descriptive, correlational)
IV- expert opinion, case study
major landmarks in history
ancient times: theory of fluids; the Greco roman period; ventricular theory
middle ages: aphasia is a memory disorder due to phlegmy ventricles.
Renaissance, 17th century, 18th century: overall advances in medicine; more thorough examinations of people with neurological conditions; soul matters; Newton’s vibes.
landmarks in history from 19th century
paul broca: it’s more toward the front
the brain of leborgne
carl wernicke: the back also matters
landmarks in history from 20th century
luria’s functional system: lang competence & lang performance
CNS: structures are housed within bone (skull/vertebral column)- brain & spinal cord.
PNS: contains nerve fibers that connect the CNS to the muscles & sense organs. Housed outside of bone.
autonomic/somatic nervous system (functional) & sympathetic/ parasympathetic nervous system
SNS: voluntary control. Pyramidal- arises from motor strip; conscious initiation of movement. Extrapyramidal- arises from pre-motor strip; provides muscle tone, background support for movement.
ANS: functions of internal organs & glands. Sympathetic system- responds to stimulation thru energy expenditure (fight or flight- raise heart rate). Parasympathetic system- responsible for quieting the body & conserving energy (undoing sympathetic stimulation)
2 layers of tough lining mostly attached to skull; most superficial
falx cerebri- separates 2 hemispheres of cerebrum; mid-sagittal divion of cerebrum
falx cerebelli- separates 2 hemispheres of cerebellum
tentorium cerebelli- horizontal dural shelf at base of skull that deivides cerebral & cerebellar regions
arachnoid mater- lacey, spiderlike lining; many blood vessels thru this space; cerebrospinal fluid flows thru this layer
pia mater- thin fascia-like covering; closely follows the contours of brain
function: protect brain; hold structures in place during movement; provides support for brain structures.
ventricles & cerebrospinal fluid
CSF: surrounds CNS- provides cushion for neural tissue; participates in nutrient delivery & waste removal. Flows thru 4 ventricles in brain & arachnoid mater- CSF is produced by choroid plexus within each ventricle.
Lateral ventrical (paired)- composed of 4 spaces bounded superiorly by the corpos callosum & extending into each of the lobes of cerebrum
3rd ventricle- located b/w left & right thalami & hypothalami
4th ventricle- diamond shaped; projects upward from central canal of spinal cord & lower medulla.
cerebrum structure & organization
grey matter (cortex)- flat sheet of cells; has many folds to reduce volume.
White matter- connects the cerebrum to the rest of nervous system; strads of cells from bottom of sheet; connections within cerebrum as well (corpus collosum connects 2 hemispheres- white matter)
Divided into right & left hemispheres, each divided into 5 lobes.
3 cell types- pyramidal cells (involved in motor function, with distant connections); nonpyramidal cells (small & star shaped, with local connections; sensory or intercommunicative in function); glial cells (provide nutrition & waste disposal; provide blood-brain barrier)
vertical organization- from superior to deep- molecular layer- glial cells, incoming axons from other layers; eternal granular layer- small pyramidal cells; external pyramidal layer- large pyramidal cells; 2 external layers mostly for motor function.
longitudinal fissure- separates right & left hemispheres.
Sulci- valleys (valleys still contain grey matter)
4 lobes plus insular lobe deeper within folds of cerebrum (bounded by circular sulcus) plus limbic system- collection of structures related to emotion & affect.
frontal lobe landmarks
most cognitive functions (higher thinking); planning (including motor tasks); initiation & inhibition of activity
broca’s area (frontal operculum)- important for speech motor planning
orbital region- the region of the inferior frontal gyrus overlying the eyes (associated with memory, emotion, motor inhibition, & intellect)
precentral gyrus (motor strip)- site of initiation of voluntary motor movement
parietal lobe landmarks
location for somatic (body) sensory reception (not special external senses)
postecentral gyrus (somatosensory cortex)- sensory counterpart to the motor strip; organized in the same way (contralateral & inverted)
temporal lobe landmarks
site of aditory reception (important for auditory & receptive lang processing)
heschl’s gyrus (area 41)- all auditory info is projected here
area 42- higher order processing region for auditory stimulation
wernicke’s area (area 22)- damage here results in disturbances of spoken lang decoding
occipital lobe landmarks
region responsible for receiving visual stimulation & higher-level visual processing
involved with maintaining the body (blood chemistry, hydration) & with emotion
subcortex landmarks & functions
limbic system- integration points for info to/from cerebrum & cerebellum & brainstem
basal ganglia- motor
carotid supply- left & right internal carotid arteries feed into circle of willis.
Vertebral supply- left & right vertebral arteries combine & become basilar artyery; basilar artery feeds in to circle of willis.
Circle of willis- series of junctures b/w arteries that completely encircles optic chiasm; provides redundant pathways for blood flow to regions of cerebral cortex; interconnections are communicating arteries.
hindbrain structures & functions
primitive part of the brain involved in basic autonomic survival functions & in low-level details of movement.
Cerebellum- sensory/motor integration
Brainstem- reflexes & sensory/motor transmission. Controls basic body functions like heart rate & breathing.
Medulla- consists primarily of transmission pathways; pyramidal tract- carries signals to muscles from cortex; pyramidal decussation- motor commands from one hemisphere cross to serve the opposite side of body.
Pons- connects motor planning centers of brain to cerebellum
Since We can see in the brain, we are tempted to correlate every possible thought or action with some specific area of the brain that might light up on an image
Just b/c one area of the brain lights up, does not mean that it is the sole area responsible for a function
Just b/c one area of the brain lights up, does not mean that it is the only area that can do a function
cranial nerve assessment & disorders
I olfactory: smell; test id of odors; anosmia, frequently disrupted following TBI
II optic: vision; tests visual acuity, color vision, visual fields, pupils, papillary responses to light, accommodation & condition of optic disk; vision loss, visual field cut (hemianopsia), papilledema (optic disk swelling), pallor (fading of optic disk)
III, IV, VI: eye movement; tests by observing the eyes at rest & during volitional movements; III oculomotor- diplopia (double vision), ptosis (drooping eye lid), loss of accommodation, downward & outward rotation of affected eye. IV trochlear- diplopia, upward deflection of eye during forward gaze. VI abducens- diplopia, inward deflection of affected eye at rest, inability to rotate eye laterally
V trigeminal-facial sensation, chewing & proprioception; tests corneal reflex, jaw-jerk reflex, open & close jaw against resistance, sensitivity to touch, pain & temp in face; weakness of jaw muscles (impaired chewing), facial numbness, trigeminal neuralgia (severe facial pain), trismus (excessive contraction of facial muscles)
VII facial: facial expression, taste, sensation of tonsils, soft palate, external & middle ear, & salivation. Tested by moving facial muscles; upper & lower facial weakness (palsy), loss of taste, dry mouth (xerostomia), dysathria.
VIII vestibulocochlear- tests hearing acuity; vertigo, nystagmus, disequilibrium, deafness.
IX & X: motor- swallowing, observation of velum; sensory- gag reflex, swallowing reflex, IX- taste sensation on tongue
IX glossopharyngeal- dysphagia, dysarthria, loss of taste, anesthesia of pharynx, xerostomia.
X vagus: dysphagia, hoarseness, palatal weakness, cardiac dysfunction
XI accessory- weakness of head & shoulder muscles, comprised respiration
XII hypoglossal: weakness/atrophy of tongue (deviates to damaged side), fasciculations, dysarthria, dysphagia
other neurological causes of cognitive-comm disorders
Behavioral plasticity: macro level; behavioral level; system level
recovery vs compensation
Recovery: restoration of function within the cortex in an area that was initially lost after injury. Reperfusion hours after stroke (restoration of blood flow). Very multifaceted & based on individuals themselves, across time, & across individuals
Compensation: different neural tissue takes over functions lost after injury
neurological factors related to recovery
Hemorrhage (better recovery) vs ischemia; lesion size (specific to structures)- larger lesion results in lesser change of recovery, but it specific to structure; initial severity; time post onset.
individual factors related to recovery
Age; education; handedness (left handers have better recovery); health status.