Movement, language, neuroinflammation and stroke Flashcards
What is apraxia?
The clinical manifestation of a praxis disorder
Is an inability to perform purposeful movement despite motivation, and preserved overall neurological function
What are the different types of apraxias?
Executive apraxias= deficit in sequencing complex movements
Posterior apraxias= deficit in the spatial (spacial) construction of complex movements
What injury is more likely to cause apraxia?
More common with left brain injuries
What are the different types of executive apraxia?
Speech apraxia (slowing and incoordination of speech), limb kinetic (inability to do fine motor movements)
What are the different types of posterior apraxias?
Optic- inability to reach for objects due to visual guidance impairment
Ideomotor- failure to perform a complex motor action
Ideatinional- an inability to conceptionalise an action
What are the 3 systems mainly involved in human movement?
The corticospinal tract
Basal ganglia loop
Cerebellar loop
What is the diagram that shows how motor responses are generated through the different loops?
What are the things that need to be considered when a patient presents with problems in moving?
- Do they have good sensory inputs- good vision, vestibular function, proprioception
Planning and praxis centres- can they make a plan, sequence it and orientate it in 3D space
Disorder of effector systems- e.g. corticospinal tracts
What is the Wernicke-Geschwind model of language production?
Broca area= production
Wernicke area= comprehension
Arcuate fasiculus= connects them
Where is Wernickes area located?
In the parietal-occipital junction
What can damage to Broca’s area lead to?
Expressive aphasia; patients have a problem with speech production and are unable to find the words they are trying to say
What can damage to Wernickes area lead to?
Receptive aphasia; patients are unable to understand speech and although they can talk, is nonsence
What can damage to the arcuate fasiculus lead to?
Conductive aphasia; can be subtle- patients cannot repeat phases spoken to them
Where is language typically comprehended and generated in the brain?
85% of people- left hemisphere
What is fluent aphasia?
The patient can speak with or without sensible meaning of words
What is non-fluent aphasia?
No speaking, damage to Broca’s areas but also to the frontal lobe or connections to the vocal chords
What are movement disorders?
The term movement disorders refers to a group of nervous system (neurological) conditions that cause either increased movements or reduced or slow movements.
What are the two ways that movement disorders present?
Hypokinetic (too little movement) or hyperkinetic (too much movement)
What are examples of hypokinetic movement disorders?
Akinesia = lack of movement
Hypokinesia = reduced amplitudes of movement
Bradykinesia = slow movement
Rigidity = stiffness or inflexibility of the muscles.
What is muscle tone?
Muscle tone is the amount of tension (or resistance to movement) in muscles.
What are patterns to recognise if muscle tone is increased?
Spasticity or ‘clasp knife’
Disorders of the extra-pyramidal system
Paratonia/Gegenhalten
What is spasticity or ‘clasp knife’?
Muscle movement feels maximally stiff at the beginning and end of range
Problem with corticospinal tract/pyramidal tract
Will see a pyramidal pattern of weakness- big muscles will be relatively well conserved compared to smaller muscles
Why does spasticity occur?
Reflex pathways are always primed to contract, but there is usually descending inhibition from the cortex.
If there is a problem, no inhibition
What happens in disorders of extrapyramidal systems?
Lead pipe rigidity- leads to increased tone throughout the range of movement of muscle
What is paratonia/gegenhalten?
The patient is voluntarily resisting the attempt to examine tone- problem with executive systems; seen in delirium and dementia
What is Parkinson’s disease?
A lack of dopamine supply to the striatum in the basal ganglia.
Cells of the substantial Niagara are degenerating because of alpha- synucleinopathy (abnormal accumulation of α-synuclein in neurons and glial cells), no longer release dopamine
What are the motor features of Parkinson’s?
Causes bradykinesia, rigidity, tremor, postural instability
What is the role of dopamine in basal ganglia?
Dopamine is released from the substantial Niagara, and either inhibits or excites the striatum, causing the indirect or the direct pathway to occur in the basal ganglia. This either reinforces or stops movement
What is the diagram in how the basal ganglia affects the motor cortex?
What medication is used to treat Parkinson’s?
Replacement of dopamine- Levo-DOPA, when given with DOPA decarboxylase inhibitor, allows it to be converted to dopamine in only the CNS
What are examples of hyperkinetic disorders?
Jerky movements e.g tremor, chorea (takes the form of dance) or tics (quick twitches of muscle)
Non-jerky movements e.g. dystonia (uncontrolled muscle movements- spasms), myoclonus (brief twitches) and stereotypies (patterned movements such as head nodding)
What are the different signs of cerebellar damage?
V = Vertigo
A = ataxia
N = nystagmus (a rhythmical, repetitive and involuntary movement of the eyes)
I = Intention tremor
S = slurred/staccato speech
H = hypotonia (decreased muscle tone)
D = Dysdiodochokinesis (the inability to perform rapid alternating muscle movements)
What is an intention tremor?
A tremor that is worse towards the end of a movement
What are the causes of meningitis?
What are the equivalent of phagocytes in the neural system?
Glial cells in CNS and macrophages in the PNS
What is Uhthoff’s phenomenon?
A transient worsening of neurological symptoms related to a demyelinating disorder such as multiple sclerosis when the body becomes overheated in hot weather, exercise, fever, saunas, or hot tubs.
What can diffuse inflammation in the CNS do to patients?
Makes patients confused e.g. delirium (can occur in urinary infections in elderly who have leaky blood brain barriers)
What is Gillian Barre syndrome?
A rare disorder in which the immune system attacks the nervous system
Immune system attacks myelin or axon which damages PNS
What are the symptoms of Gullian Barre syndrome?
Firstly, symptoms are paresthesias (tingling/numbness) in hands and feet, then muscle weakness, flaccid paralysis and absent reflexes. All appear first in hands and feet.
Sometimes pain in back, shoulder and thighs
Symptoms are symmetrical
When does Gullian barre syndrome often happen?
After gastro-intestional or respiratory infections