Brainstem/ Cerebellar Flashcards
3 parts of brain stem
Midbrain
Pons
Medulla oblongata
Midbrain contains
Cerebellar peduncles (motor tracts to SC)
Super and inferior colliculi
Red nucleus
Midbrain nerves
III and IV
Inc ICP = dysfunction of nerve III -
Abnormal pupil size, poor reactivity to light
Pons has
Two resp. Centers in dorsal pons. Work w/ principle resp center in medulla
Reticular formation controls
Consciousness and attention
(Asleep, awake, alert, attending)
Also relays in an ascending pathway to thalamus, limbic, cerebral cortex
Medulla oblongata regulates
Cardiac
Vascular
Resp function
Medulla coordinates
Swallowing
Vomiting
Coughing
Sneezing
Medulla is decussation for
Dorsal column and CST
CN in medulla
Part of VIII IX X XI XII
______ of the 12 CN pairs originate from nuclie in _______
10 of the 12 CN pairs originate from nuclie in brainstem
“If you have CN involvement, you know you are in the BS”
Initial BS dysfunction
Gait distubrance Diplopia Focal weakness HA Vomit Facial numb/weak
Dorsal midbrain involvement
Parinaud syndrome
Parinaud syndrome characterized by
Loss of upward gaze
Pupillary areflexia to light
Loss of convergence
Reticular formation involvement
Apnea
Hypoventilation or hyper
Orthostatic hypotension
Syncope
BS involvement management
Equipment/orthotic evaluation – Functional training • Bed mobility, transfers, wheelchair – Gait training – Balance and coordination training – Family training
Cerebellum connects to rest of brain by
Superior, middle, inferior cerebellar peduncles
Inferior cerebellar peduncle
Carries afferent fibers coming mainly from SC
Middle cerebellar peduncles
Contains afferent fibers from the contralateral pontine nuclei
Superior cerebellar peduncle
Carries efferent fibers leaving cerebellum. Crossed afferent fibers from ventral spinocerebellar tract
There are a large number of axons projecting to cerebellum carying _____
Vestibular and proprioceptive info
Cerebellar nuclei
Dentate nucleus
Interposed nuclei
Fastigial nuclei
Biggest part of cerebellum formed by
Lateral hemisphere
Info from cerebullum goes to cortex. Used to
Plan and program voluntary movement, especially skilled, learned movement
Cerebellum:
SOS DEFTT
Smooth
Orderly
Sequencing
Direction Extent Force Timing Tone
Vestibulospinal and reticulospinal tracts
Influence spinal motor pathways and influence posture and stereotyped movements which are regulated by BG
Flocculonodular lobe receives info from
Vestibulocerebellum
vestibular nuclei
Flocculonodular lobe primary role
Regulate balance, influencing eye movement needed for visual tracking
BG PASS
Basal Ganglia
Postural
Adaptation
Semivoluntary
Semiautomatic
Cerebellum and feedback control
Comparator and error detection mechanism
Controls onset, level, rate of force production of muscles
Peripheral feedback during motor repsonse given by
Muscle spindle GTO Joint Cutaneous receptors Vestibular apparatus External info through eyes and ears
Closed loop
Feedback used as references for correctness, compilation of error and subsequent correction in order to maintain desired state
Feed forward
Predictive compensatory modifications
- cerebellum programs voluntary movement skill based on memory of previous sensory input and motor output
- vital to anticipatory muscle activity
Stereotyped movements and rapid short duration movements
Controlled by open loop
Open loop system
Control system w/ preprogrammed instructions to effector that does not use feedback info and error detection processes
-control from motor program memory/preprogrammed pattern of info for controlled movement
If cerebellum is damaged
Learned motor program cannot be used
-movement guided by feedback systems
-movement is slow and uncoordinated
Inability to adapt to minor changes
Cerebellum - disturbed balance
Difficulty maintaining upright posture
Visual compensation not effective
Cerebellum hypotonicity
DTR normal
-decreased excitation from deep cerebellar nuclei to regions of brain that excite alpha and gamma motor neuron
Dysmetria
Deficit in reaching target
Inability to judge distance or ROM
Over or under shooting (hyper/hypo metric)
Disdiadochokinesia
Inability to perform rapidly alternating movements
-movements are irregular w/ rapid loss of range and rhythm esp as speed is increased
Movement decomposition (dyssynergia)
Movement performed in its component parts instead of one coordinated movement
Asynergia
Inability to associate muscle groups together for complex movements
Ataxia most often associated w/
UE/LE/trunk/head/mouth/trunk
*Gait disturbances
Wide BOS, steps irregular in direction and distance
Ataxia initation of LE movement
May start slow then extremity may unexpectedly be rapidly flung to hit floor
- arms held out to improve balance
- gait is generally instead, irregular, staggering
Asthenia
Generalized muscle weakness associated w/ cerebellar lesion
Muscle strength on involved side can be reduced by 50%
Intention tremor
Occur during voluntarily movement and ted to increase as extremity reaches its intended goal
Speech disturbances (dysarthria)
Rhythm of speech is changed. Syllables are slow, accents misplaced.
Grammar and word selection not involved
Cerebellar involvement: control of eye movement and gaze
Deviate toward contralateral side, inability to move accurately to target in periphery
- saccades either too large or too small
- nystagmus is rhythmic, quick oscillatory movement of eyes
BS stroke AICA
Pontomedullary syndrome
Pontomedullary syndrome
Severe vertigo Dysarthria Altered precaution of vertical Ataxia *Loss of pain/temp ipsi face, contra body Oculomotor abnorm *Unilateral hearing loss
BS stroke PICA
Lateral medullary syndrome
Lateral medullary syndrome
Severe vertigo Dysarthria Altered perception of vertical Ataxia Loss of paintemp ipsi face, contra body Oculomotor abnormal *horners syndrome
Friedreich’s ataxia
Eti
Genemutation —> mitochondrial function
Autosomal recessive
Friedreich’s ataxia characteristics
Gait unsteadiness: 5-15yo
- UE ataxia, dysrarthirai, paresis (esp LE)
- mental function decline
- reflexes, vibration, position sense lost
- clubfoot, scoliosis, progressive cardiomyopathy
Friedreich’s ataxia prognosis
- by late 20s, pt may be confined to W/C
- death , arrhythmia or heart failure, usually by middle age
Spinocerebellar ataxias (SCA)
Autosomal dominant
Most common affect multiple areas in CNS and ONS: neuropathy, pyramidal signs, restless leg syndrome, ataxia
Some SCA only cause cerebellar ataxia
SCA type 3/ machado-Jospeh disease
Most common inherited SCA worldwide
Ataxia, Parkinsonism, possibly dystopia, facial twitching, ophthalmoplegia, bulging eyes
AOA 1
Ataxia oculomotor apraxia
Autosomal recessive
Aprataxin
Onset folder-adolescent
AOA 1 S/s
Horizontal and vertical oculomotor apraxia
DTR disappear early
Axonal neuropathy —> distal muscle wasting
Dysarthria develops, choreoathetosis frequnent
Possible pyramidal signs
AOA2
Autosomal recessive
Senataxin
Onset pre and early teens
Progressive cerebellar ataxia followed by oculomotor apraxia and sensorimotor neuropathy
