Cerebellum Patho Flashcards
Cerebellar nuclie w/in each cerebellar hemisphere
Denate nucleus
Interposed nuclei - emboliform, globase
Fastigial nuclei
Info from the cerebellum is used to
Plan and program voluntary movement, skilled learned movement
Cerebellum anatomy and function
Integrated structure critical for environmental adaptations
Compares ongoing movement w/ motor command from cortex
Flocculonodular lobe received most of its info from
vestibular nuclei
Flocculonodular lobe primary role
Regulate balance, influence eye movements needed for visual tracking
Peripheral feedback to cerebellum by
Muscle spindles GTO Joint and cutaneous receptors Vestibular apparatus Eyes and ears
Closed loop system
Control system employing feedback which is used as a reference for correctness, a computation of error and subsequent correction in order to maintain a desired state
Cerebellum is also Feed forward control
Program voluntary movements based on memory
Performs predictive compensatory modifications of reflexes in preparation for movement w/ input from basal ganglia
Vital to anticipatory muscle activity
Cerebellum as Open loop system
Preprogrammed instructrtions to effector that does not use feedback info and error detection processes
Stereotyped movement and rapid short duration - do not allow sufficient time for feeedback and are controlled by open loop system
Originates from motor program, memory or preprogrammed pattern of info
If cerebellum is damaged
Learned motor program cannot be used —> movement guided by feedback systems through the cerebrum similar to learning a new skill —> slow and uncoordinated —> inability to adapt to minor changes
Cerebellar - disturbed balanced/equilibrium
Difficulty maintaining upright posture
Visual compensation is not effective
Cerebellum - hypotonicity
Decrease in excitation from deep cerebellar nuclei to regions of the brain that excite alpha and gamma motor neurons
DTRs typically normal
Cerebellum - dysmetria
Inability to judge distance or range of movement
Deficit in reaching a target effectively
Dysdiadochokinesia
Inability to perform rapidly alternating movements
Movements are irregular w/ a rapid loss of range and rhythm, esp as speed is increased
Cerebellar 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
Lack of order- uncoordinated movement
Most often associated w/ disturbances of gait, wide BOS, steps are irregular in direction and distance
Initiation of LE movement may start slowly then extremity may unexpectedly be rapidly flung to hit floor
Arms usually head outward to improve balance in high garud position
Asthenia
Generalized muscle weakness can be associated w/ cerebellar lesions
Muscle strength on involved side can be reduced by 50%
Tremor
Involuntary oscillatory movement resulting alternating contractions of opposing muscle groups
Intention tremor
Occur during voluntary movements, tend to increase as extremity reaches its intended goal
Cerebellar dysfunctions - speech disturbances
Rhythm of speech is changed
Syllables are slow and accents mistplaced
Grammar and word selection are not involved
Cerebellar dysfunction - control of eye movements and gaze
Inability to move eyes accurately to a target in the periphery, including overshooting and undershooting the eyes when attempting look at a target
Saccades are either too large or too small
Systagmus is rhythmic, quick oscillatory movement of eyes
Cerebellar dysfunction management
Equipment/ orthotic eval Functional training Gait training Balance and coordination training Family training
