Cerebellar Pathology Flashcards
Cerebellum has direct influence of ________, posture, muscle tone and _____________.
(1) Equilibrium
(2) initiation and force of movement
Cerebellar Ataxia
Describes loss of muscle coordination (as result of cerebellar pathology) and affects (1) gait (2) posture and (3) patterns of movement and is linked to difficulty initiating movement as well as errors in the rate, rhythm and timing of responses.
Injury to the midline (vermis, paleocerebellum) which underlie what deficits ?
titubation, truncal ataxia, orthostatic tremor, and gait imbalance
Injury to the hemisphere (neocerebellum—right controlling the R side of body and Left controlling left side) contribute to ?
Limb ataxia (eg dysdiadochokinesia, dysmetria, and kinetic tremor), dysarthria, and hypotonia
Injury to the posterior cerebellum (flocculonodular lobe, archicerebellum) influence posture and gait as well as eye movement disorders and cause what deficits?
Nystagmus, vestibular-ocular reflex disruption
Asthenia
Generalized muscle weakness associated with cerebellar lesions
Dysarthria
Disorder of the motor component of speech articulation.
Referred to as scanning speak (one-word-at-a-time quality)
Speech pattern typically : slow, may be slurred, hesistant with prolonged syllables and inappropriate pauses.
Word selection and grammar remain intact, but the melodic quality of speech is altered
Dysdiadokinesia
Impaired ability to perform rapid alternating movements.
Observed in movements such as rapid alternation bt pronation and supination of the forearms.
Movements are irregular, with rapid loss of range and rhythm especially as speed is increased
Dysmetria
An ability to judge the distance of range of a movement.
May be manifested by an overestimation (hypermetria) or an underestimation (hypometria) of the required range needed to reach an object or goal
Dyssynergia (movement decomposition)
describes a movement performed in a sequence of component parts rather than as a single, smooth activity.
I.e.—patient asked to touch nose: patient will first flex the elbow, and then adjust the position of the wrist and fingers, and further flex the elbow, and final flex the shoulder
Asynergia
Loss of ability to associate muscles together for complex movments
Gait ataxia
Involves ambulatory patterns that typically demonstrate a broad BOS. Gait pattern typically instead (postural instability), irregular, and staggering with deviations from an intended forward line of progression (veering to one side; swaying or pitching in different directions)
Upright stance stability is often poor and the arms may be held away from the body to improve balance (high guard position)
Stepping patterns are irregular in direction and distance. Initiation of forward progression of a LE may start slowly and then the extermity may unexpectedly be flung rapidly and forcefullly Forward and audibly hit the floor.
Hypotonia
Decrease in muscle tone.
Believed to be disruption of afferent input form the stretch receptors and/or lack of cerebellum’s facilitatory efferent influence on the fusimotor system
What may happen in a patient with a cerebellar pathology when test L4 DTR?
Instead of the knee returning immediately to resting position, it may oscillate 6-8 times before returning to rest.
Nystagmus
Rhythmic, quick, oscillatory, back and forth movement of the eyes that causes difficulty with accurate fixation and vision and is believed linked to the cerebellum’s influence on synergy and tone of the extraocular muscles.
Typicall apparent as the eyes move away from midline ot fix on an objec in either the Medial or lateral field (ie extremes of temporal or nasal vision)
