BG Nuerophys and Disorders Flashcards
BG Neurophysiology, disease, and disorders [Huntington's, dystonia, Tourette's]
What are the primary movement disorders of the BG
Hypokinesia (PD)
Hyperkinesia (Huntington’s disease, tourette’s, dystonia)
Dyskinesia
What composes the BG
Caudate nucleus
Putamen
GP
w/some STN and substantia nigra
T or F: BG has direct output to motor units
FALSE ! It is always through the VL of the thalamus then to the the motor cerebral cortex
What is SNc
Substantia nigra pars compacta
What is SNr
Substantia nigra pars reticulata
What is a flow through the cortex and BG?
Cortex –> Striatum (Caudate and Putamen) –> [STN, LGP/EGP, MGP/IGP, SNr, SNc) –> VL of thal –> Cortex
What composes the striatum
Caudate nucleus and the putamen
__ is Faciliatory/Inhibitory from x?
a) GLU (glutamate)
b) GABA
c) dopamine (DA)
a) Faciliatory input from STN and cortex
b) Inhibitory to Thalamus
c) can be either
Output from the thalamus is (inhibitory/faciliatory) to the cortex
Faciliatory
What drives the excitability of the cortex?
THE THALAMUS
What could cause a hyperkinetic movement disorder?
[Decreased inhibition of thal]
- Too little GABA to inhibit the thalamus causing over facilitation of the cortex
- Too little glutamate to cause the release of GABA
What could cause a hypokinetic movement disorder
[Increased inhibition of thal]
- Too much GABA causing inhibition of the VL thalamus to dec facilitation of the cortex
What is the prevalence of Huntington’s Disease?
6.5/100,000 but highest in Mauritius at 1/2100
What is the typical onset and course of Huntington’s?
after 30 yrs dx
death 15-20 yr later
What type of disease is HD
Hyperkinetic Autosomal dominant disease on the short arm of chromosome 4 (too many CAG repeats)
What is the neurophys of HD?
Degeneration of SNr and LGP leading to dec GABA (underinhibition of thal-> overfacil of cortex) and increased DA and norepinephrine
What are symptoms of HD (List)
Chorea/Choriform mvmts Akinesia & Bradykinesia Gait variations Dysarthria Dysphagia Vision problems Cognitive problems Psychosocil problems
What are chorea/choreiform movements
Involuntary, purposeless, non-repetitive, small and/or large A mvmts
When in HD are akinesia and bradykinesia evident
Later stages or w/too high dose of med
What vision changes occur w/HD
Poor control of saccade mvmts, target undershooting, latency in mvmt initiation
What cognitive problems occur in HD
Poor memory and judgement
Impulsive
Slow processing
What psychosocial problems occur in HD
Personality changes, mood swings, aggression, irritability, depression, apathy, suicidal ideation
What is the Unified HD Rating Scale? (UHDRS)
A multicomponent way to stage HD that includes: Motor Cognition Behaviour Independence Functional activities Total Functional capacity
Define dystonia
Hyperkinetic disorder w/Abnormal mm tone w/simultaneous contraction of agonist and antagonist to cause contorted or twisted postures and can occur w/task-specific activities
What is the duration of dystonia?
Few seconds, minutes, hours or longer
T or F: Dystonia is not painful
False - it can be very painful
What part of the body is influenced w/_ dystonia?
a) Generalized
b) Focal
a) Full body
b) One jt or few related joints
List some types of Focal Dystonia
Pharyngeal
Cervical
Writer’s Cramp
Musician’s Cramp
Pharyngeal dystonia
Distorts speech via involuntary contract of vocal chords and can be treated w/botox
Cervical dystonia
MOST COMMON!
Hypertrophy of SCM to cause invol contraction of neck causing Lat fwd flex w/rot away
What is the most common dystonia
Cervical dystonia
Writer’s cramp
A task-specific focal dystonia that causes a spasm to affect certain mm of the hand/fingers
Musician’s cramp
A task-specific focal dystonia that causes spasms of certain mm of hand/fingers
What is the onset and progression of Generalized dystonia
About 8 yo that is a chronic progressive, and debilitating disease
What is the onset and progression of Focal dystonia
About 30-50 yo for onset that is also chronic, progressive and may plateau after 5 years
What are some treatment of generalized dystonia?
Meds: Baclofen, Artane, Sinemet, Klonopin
Sx: DBS of GP or Rhizotomy
What is a treatment of focal distonia?
Botox that is effective for 3-4 mo
Define Tourette’s syndrome (TS)
Hyperkinetic disorder w/Impulsions and compulsions to perform fragments of motor programs
What s/s must be present for TS
> = 2 motor ticks
= 1 vocal/phonic tic
In some combo over the course of more than a year
List some simple motor tics in TS
Eye blinking Facial grimacing Jaw mvmts Head mvmts Shldr shrugging Neck Stretching Arm jerking
What are complex motor tics in TS
Involving multiple mm groups or combo of mvmts and are more purposeful (hopping, twirling, jumping, skipping)
What are simple vocal/phonic tics in TS
Sniffing Throat clearing Grunting Hooting Shouting
What are complex vocal tics in TS
Words or phrases that are not recognizable but occur out of context
Words could be inappropriate
What is the progression of TS
Tics emerge b/t 5-7 yo most often as a motor tic
Severity inc at 8-12 yo
Late adolescence is noticeable improvement
T or F: Tics can disappear in adulthood w/TS
True - a minority of people continually have tics into adulthood
What is the prevalence of TS
1/160 kids b/t 5-17 in US
= 300,000 kids in US
Is TS more common in boys or girls?
3-4x more likely in boys
