Basal Ganglia & Cerebellum Flashcards
Spasms
– sudden involuntary contractions
Cramps
– severe spasms
Fasciculations
– quick twitches of muscle fibers of a single motor unit – visible
Myoclonus
– brief involuntary contractions of muscle or group of muscles
Akinesia (Dyskinesia)
- Hyper and Hypo
- Impairment of voluntary movement
- Most abnormal movements occur in extrapyramidal system
- Basal ganglia
- All tracts outside of pyramidal tracts
- Pyramidal tracts are those connecting with pyramidal cells of motor cortex for voluntary movement
Hypokinesia
- Poverty of movement
- Mostly related to Parkinson’s disorders (3)
- Festinating gait – Marked by very small rapid steps and occurs in persons with Parkinson’s disease when the posture of the head and trunk involuntarily lean forward ahead of the feet, moving the center of gravity forward. Rather than taking a large step to correct the imbalance, several hurried small steps increasing gait velocity occurs, resulting in running or “chasing” one’s center of gravity, which remains in front of the feet.
- Bradykinesia – Slowness or poverty of body movement
Hyperkinesia
- Rhythmic or nonrhythmic excessive movement
- Rhythmic: regular alternating or oscillatory
- At rest (resting tremor)
- During attempted movement (intention tremor)
Tardive Dyskinesia
– (side effect of neuroleptic drugs)
-involuntary movement disorder most often characterized by puckering of the lips and tongue and/or writhing of the arms and legs.
Tics
– nonrhythmic, rapid, suppressible movements that are simple or complex, idiosyncratic, repetitive, and done almost unconsciously.
- They can be suppressed only for brief periods and with conscious effort.
Tourettes Syndrome
– hereditary tic disorder that begins in childhood.
-Symptoms include simple, complex, and vocal tics.
Fibrillations
– brief contractions of single muscle fibers (not visible)
Chorea
– nonrhythjmic, jerky, rapid, nonsuppressible movement that involves mostly distal muscles or the face
- movements may merge imperceptibly into purposeful or semipurposeful acts that mask the involuntary movement.
- Caused by dopaminergic overactivity in the basal ganglia.
Huntington’s chorea
– Degenerative disease of the basal ganglia in the brain.
- characterized by abnormalities in postural reactions, trunk rotation, distribution of tone, and extraneous movements.
Athetosis
– nonrhythmic, slow writhing, sinuous movements, predominantly in distal muscle
- alternating postures of the proximal limbs often blend continuously to produce a flowing stream of movement.
- Athetosis often occurs with chorea as choreoathetosis.
- Caused by dopaminergic overactivity in the basal ganglia.
Hemiballismus
– (ballistic movement) nonrhythmic, rapid, nonsuppressible movement characterized usually by unilateral, violent, flinging movements of the proximal arm.
-Caused by a lesion, usually an infarct, around the contralateral subthalamic nucleus.
Dystonias
– sustained involuntary muscle contractions, often distorting body posture.
- Distorted positioning of limbs, neck, or trunk held for few seconds, then released.
-Generalized dystonia – rare, progressive and characterized by movements that result in sustained, often bizarre postures. Often hereditary.
Focal dystonias
– affect a single body part.
- Can be periodic, random or progressive
- Meige’s Disease – involuntary blinking, jaw grinding, and grimacing (3)
- Spasmodic Torticollis – begins with a pulling sensation followed by sustained torsion and deviation of the head and neck
- Hemifacial spasm – unilateral painless, irregular contractions of the facial muscles due to impairment of the 7th cranial (facial) nerve.
- Dystonic Writer’s cramp – (Occupational dystonia) focal dystonic spasms initiated by performing skilled acts (eg. Writer’s or typists’s cramp)
BASAL GANGLIA
- Caudate nucleus,
- Putamen,
- Globus Pallidus
- Subthalamus (diencephalon),
- Substantia nigra (midbrain)
Lenticular nucleus
Putamen & GP
Corpus striatum
Caudate & Putamen
OUTPUT NUCLEI
Sn Reticularis + GP (medial/internus)
Basal Ganglia functions
Planning
Execution
Voluntary Movement
Automatic learned movement
PLANNING AND EXECUTION
-Computes what motor response is appropriate for the environment, cognitive demands, and emotional situation
Generate output -Globus pallidus -Substantia nigra Project to the Thalamus -Ventral lateral nucleus -Ventral anterior nucleus
FUNCTIONAL REGIONS OF CEREBELLUM
-Receives inputs from Vestibular system, SC & Brainstem
3 functional regions:
- Vestibulocerebellum: Equilibrium
- Spinocerebellum: Gross limb mvmts
- Cerebrocerebellum: Fine distal limb mvmt
Cerebellum assists with:
Planning of movement
Coordination of movement
Timing of movement
Postural control
AMBULATION
- Cortex: Goal orientation + Ankle control
- BG: Force generation
- Cerebellum: Timing, coordination + error correction
- SC: Spinal pattern generation
- Somatosensory cortex: Sensory info for adaptation
Medulla / Pons
- regulate function of vital organs Four D’s: -Dysarthria -Dysphagia -Dysmetria -Diplopia
- Disordered consciousness
- Locked in syndrome
- Vegetative state
Vestibulocerebellum (flocculonodular lobe) and vermis lesions:
- Disturbances in balance
- Swaying & postural instability
- Wide gait
- Titubation in trunk (swaying, shaking of trunk)
- Nystagmus
- Vomiting
Vermis syndrome:
- bilateral signs,
- head and trunk, and falling forward or backward
Lateral portions of the cerebellum (spinocerebellum and cerebrocerebellum):
- Ataxia of limbs (dysmetria, dysdiadochokinesis……..)
- Vomiting
- Nystagmus
- Balance disturbances
- Unilateral lesions-ipsilateral signs (especially arms)
- Falling on side of lesion
Most common signs of Cerebellar Disorders
Hypotonicity Ataxia No paralysis or atrophy Dysdiadochokinesis Dysmetria Intention tremor Decomposition of movement Asthenia Rebound phenomenon Speech dysarthria Fall to the side vs. forward or backwards
Huntington’s Chorea
-Autosomal dominant hereditary, progressive neurological degeneration in many areas of the brain, most prominently in the striatum and cerebral cortex.
-Characterized by choriform movements.
Intellectual deterioration.
-Age, gender, and race.
-Typically after age 30
-M/F usually affected same
-Usually more in African American
Pathology:
-degeneration of the basal ganglia
-(cognition, coordination, voluntary mvmt)
-decrease in the production of GABA
-degeneration of the cerebral cortex
Huntington’s treatment
- Administration of cholinergic drugs.
- Anti-epileptic medications
- Increase GABA? (not shown effective)
- Medications to control hallucinations, anxiety, & irritability.
- Rehabilitation services:
- Maintain quality of Life.
- Address self-care, & cognitive problems
Muscular Dystrophy (MD)
- A group of genetic, hereditary skeletal muscle metabolism disorder.
- Leads to progressive atrophy/hypertrophy of muscles, muscle paresis, and paralysis.
MD Signs & Symptoms
Muscle weakness Lumbar lordosis & scoliosis Waddling gait Droopy eyelids Open mouth Dysphagia Cardiomyopothy Fatigability Low tone in facial muscles Difficulty rising to stand (Gower’s sign)
Pseudohypertrophic (Duchenne’s) MD
Most common type. X-linked (female carriers) See in males Onset age 3-6 years. Weakness. Cardiac involvement (95%). Pseudohypertrophy. Rapid course. Shorter lifespan
Fascioscapularhumeral MD
- Autosomal and dominant.
- Males & females affected equally.
- Onset age 7-12 years.
- Characterized by weakness in face, shoulder girdle/scapula, and triceps & biceps before pelvis.
- Minimal disability.
- Live close to life expectancy.
Limb Girdle (Erb’s) MD
- Autosomal recessive.
- Onset age 5-10 years.
- Pelvis & shoulder girdle primarily involved.
- Diverse group of disorders with 20% having hypertrophy.
- Weakness is generally symmetric, proximal, and slowly progressive, cardiomyopathy.
- Severe disability mid-life.
- Shorter life span.
MD Interventions
- Family support;
- Prevention of secondary contractures;
- Use of assistive devices;
- OT/PT encourage developmental activities and maintain optimal functioning level;
- Avoidance of obesity.
Parkinson’s Disease (PD)
- Lack of dopamine production by the substantia nigra.
- Results in an increase in involuntary movements (shaking palsy).
- Etiology:
- viruses
- infections
- encephalitis
- tumors
- psychotropic drugs
- Familial tendency to develop the disease.
Clinical signs of PD
Rigidity:
- Leadpipe rigidity
- Uniform resistance to mvmt
- Cogwheel rigidity
- Tense, relax, tense, relax
- Bradykinesia
- Resting Tremor
- Posture
- Hunched, stoop, no arm swing, lack of affect
- Gait Problems:
- Festinating gait ,
- Poor equilibrium
- Loss of reciprocal arm swing
- Other Signs:
- Masked face
- Monotonous speech
- Dysphagia & drooling
- Decreased eye blink
PD Interventions
L-Dopa
DBS (Deep Brain Stimulation)
- Subthalamic Nucleus
- Globus Pallidus Interna
Put small electrodes in brain to stimulate.
Good success rate
“Off” phase – no medication
“On” phase – with medication
