Stroke and Language Flashcards
what is a stroke/what causes it?
When blood supply is disrupted
risk factors
o Old age
o High BP
o Obesity
o Lack of exercise
o Poor diet
o Smoking
o Inflammation
o Prior/family history
o Stress
o Men more likely than women but women live longer so have more ‘exposure’
Ischaemic stroke:
- Most common (85%)
- Artery blocked by blood clot
- Cell death from hypoxia and lack of glucose
- Secondary excitotoxicity
Haemorrhagic stroke:
- Artery breaks or leaks
o Hypertension, aneurysm, etc - Cell death from raised intracranial pressure and inflammation
o Also hypoxia and lack of glucose
o Secondary excitotoxicity
Glutamate – excitotoxicity causes neuronal cell damage
explain the process
- Stroke
- Glutamate neurons die due to hypoxia
- Release large amounts of glutamate into extracellular space
- (Over) stimulation of nearby neurons
a. All glutamate receptors activated
b. Massive calcium influx
c. Activates proteases and endonucleases - Kills neuron…
- …which releases large amounts of glutamate into extracellular space
- (Go to Step 4)
consequences of stroke
- Depends on the brain region damaged and which hemisphere it is in
Hemineglect:
- Ignoring senses/signals/things on one side (can’t see them)
Neglect
sign of posterior parietal cortex damage
- Normally on the right hemisphere
o So affects sensory processing on the left
o Right hemisphere attends to left + right
o Left hemisphere attends only to right
- Sensory neglect
o incoming sensory information from the contralateral hemispace is ignored
- Conceptual neglect
o neglect of the body and the external world in the contralateral hemifield
- Hemiasomatognosia
o patient denies that affected side of body belongs to them
- Motor neglect
o fewer movements in the contralateral space
role of right parietal cortex
Sensory and spatial processing
role of Left posterior parietal cortex
spatial awareness and planning
apraxia
difficulty in performing motor tasks even though primary motor pathways intact
Ideomotor apraxia
difficulty in responding to motor instructions
Ideational apraxia
difficulty in conceptualising motor tasks
Gerstmann Syndrome:
- Arises from damage to the Inferior Parietal Lobe
o On the dominant (normally left) side - E.g. from a stroke affecting the relevant branches of the MCA
- Dysgraphia/agraphia – problems writing
- Dyscalculia/acalculia – problems with maths
- Finger agnosia – problems distinguishing fingers
- Left-right disorientation
agnosia
inability to recognise sensory stimuli
damage to Inferior Temporal Cortex
o Visual agnosia (“Psychic blindness”)
Patient can see, but not identify
o Prosopagnosia (Face Blindness) - Fusiform gyrus
inability to recognise individuals from their faces. Patients can describe the constituent parts of the face and can identify the subject by voice, clothes and other cues
damage to Middle Temporal Cortex
o Movement agnosia (Akinetopsia)
Cannot distinguish between moving and stationary
World is a series of ‘still images’
- Dysarthria
difficulty moving the muscles of the face and tongue that mediate speaking
aphasia
difficulty in naming objects, repetition of words is impaired
Wernickes area:
- Brodmann 22 (L)
- Understanding language
Wernickes aphasia:
- Unable to understand language
- Fluent speech, but makes no sense
o (assuming Broca’s area intact)
o Little repetition
o Adequate syntax and grammar
o Contrived or inappropriate speech - Damage to Wernicke’s area
o Often as a result of a stroke
o Branches of the Middle Cerebral Artery - Also called fluent, sensory or receptive aphasia
- Patients are not really aware of the deficit
Brocas area:
- Brodmann 44 and 45 (L)
- Creating language
Broca’s aphasia:
- Few problems understanding language
o Assuming Wernicke’s Area intact - Difficulty constructing their own
o Halting speech – makes sense?
o Repetitive
o Disordered syntax + grammar
o Disordered structure of individual words - Also called non-fluent, motor, expressive, or production aphasia
- Damage to Broca’s area
o Often as a result of a stroke
o (Different) branches of the Middle Cerebral Artery
Articulate fasciculus (L):
- Connects broca’s and wernickes areas
Conduction aphasia:
- Can normally understand and produce language
o Assuming broca’s and wernicke’s area are intact - Repetition and sequencing are impaired
- Phonemic errors
o Smole rather than smile
o Gar rather than jar - Patient is aware
Anomia (anomic aphasia):
- Difficulty in naming objects
o Almost all other language is OK
o Knows what the object is, what it is used for
(so different to agnosia)
o Presents as a ‘tip of the tongue’ problem - Can arise from damage to left Arcuate Fasciculus and Brodmann Area 22 (mild) and possibly temporal/parietal cortices
o Tho may feature in other aphasias
Treatment for aphasias:
- Long-term prognosis is good
- Speech therapy (learn how to manage deficits)
- Plasticity within and around damaged areas
- Right hemisphere compensation
- Right hemisphere communication disorder:
o Language is normally OK-ish
o Prosody can be impaired (Aprosodia)
Flat, and emotionless language
Difficulty understanding emotions in language
Humour, sarcasm, reduced recognition and use
o ‘Pragmatic difficulties’
Misunderstand context and ‘big picture’
Difficulties taking turns
o More likely overshadowed by other deficits
E.g. neglect in right PPC
