6 Cerebellar Dysfunction Flashcards
Cerebellum connection to brainstem
- superior cerebellar peduncle- attach to midbrain, contains cerebellar efferent fibers
- middle cerebellar peduncle- to pons, afferent fibers from cerebral cortex
- inferior cerebellar peduncle- to medulla, afferent from brainstem and spinal cord, efferent to vestibular and reticular nuclei in brainstem
Cerebellum inputs and outputs
- inputs- mossy fibers (information); climbing fibers (timing)
- outputs- Purkinje cells
Vestibulocerebellum
- regulates equilibrium
- involves vestibular nuclei, superior colliculus, reticulospinal system, primary motor cortex
- deep nucleus- fastigial
Spinocerebellum
- regulates gross limb movements
- involves spinocerebellar tracts, vestibulospinal and reticulospinal tracts, motor cortex, red nucleus
- deep nuclei- emboliform and globose
Cerebrocerebellum
- regulates distal limb voluntary movements
- motor planning
- timing/rhythm
- involves cerebral cortex via pontine nuclei, motor and pre-motor cortices via thalamus, red nucleus to activate rubrospinal tract
- deep nucleus- dentate
Stroke location leading to cerebellar dysfunction
- basilar artery branching to superior cerebellar artery, AICA
- vertebral artery branching to PICA, posterior spinal artery
Tumors to cerebellum
- can affect cerebellum, pons, medulla, and/or fourth ventricle
- most common primary posterior fossa tumors- medulloblastoma, astrocytoma
- most common primary sites of posterior fossa metastases- lung (50%), breast, kidney, melanoma
Toxicity to cerebellum
- cerebellar cortex and Purkinje neurons especially vulnerable to intoxication and poisoning
- most common is alcohol-related- Wernicke-Korsakoff syndrome, vitamin B1/thiamine deficiency
- anti-convulsants, anti-neoplasticism, lithium salts
- cocaine, heroin
- mercury, lead, manganese
Infection to cerebellum
- post-viral cerebellar ataxia, acute cerebellar ataxia, acute cerebellitis
- most common in children who had chickenpox
- most make complete recovery
Endocrine effects on cerebellum
- hypothyroidism-induced ataxia is reversible with thyroid replacement therapy
- Hasimoto’s/autoimmune thyroiditis not response to replacement therapy
Multiple sclerosis affecting cerebellum
- ataxia, tremor
- large-amplitude, postural tremors most commonly affect arms (sometimes head, neck, vocal cords, trunk)
Nutrition affecting cerebellum
-gluten ataxia most common cause of sporadic idiopathic ataxia
Spinocerebellar ataxia
- degenerative genetic condition
- multiple types, varying severity and age of onset
Friedrich’s ataxia
- early-onset hereditary spinal ataxia (8-15 y/o)
- progressive condition, initially clumsiness of gait
- scoliosis and foot deformities common
- cause of death usually heart failure
Chiari malformation
- herniation of part of cerebellum and/or brainstem through foramen magnum to upper spinal canal
- often congenital
- may be asymptomatic until adolescence or adulthood
Dandy-walker syndrome
- congenital malformation of enlargement of fourth ventricle and partial or complete absence of cerebellar vermis
- varying degrees of physical and intellectual impairment
- hydrocephalus and progressive skull enlargement common
Hypoplasia
- small or under-developed cerebellum
- associated with several congenital conditions
- developmental delays, ataxia, hypotonia, and nystagmus common
Types of ataxia
- cerebellar- Romberg’s imbalance with eyes open and closed
- sensory- loss of proprioception, Romberg’s imbalance with eyes closed only
- vestibular- imbalance when forced to relay on vestibular cues or with head turns, also nausea, dizziness, etc.
Dysdiadochokinesia
-impairments in rapid alternating movements
Dyssynergia
-impairments in coordinating multi-joint movements
Decomposition of movement
-breaking down movement into series of smaller, single-joint motions
Dysmetria
-impairments in ability to judge and scale movement distances
Cerebellar tremor
-action or intention tremor, not resting
Cerebellar ataxic gait
-wide BOS, variable step length and limb trajectories, path deviations, decomposition of movement