Disorders Of Cerebellum (handout based) Flashcards
Consists of the vermis of the anterior lobe, the pyramids, the uvula, and the paraflocculus
Paleocerebellum
Plays a role in the control of muscle tone and the axial and limb movements
Paleocerebellum
Consists of the middle portion of the vermis and most of the cerebellar hemispheres
Neocerebellum
Projects fibers to the cerebral cortex through the thalamus
Neocerebellum
Plays a role in the planning and initiation of movements, as well as regulation of fine limb movements
Neocerebellum
Receives input from areas of the brain concerned with eye movements
Archicerebellum
Plays a role in the control of body equilibrium and eye movements
Archicerebellum
Composed of stellate cells, basket cells
Molecular layer of the gray mater of cerebellum
Composed of Purkinje cells, which are large Golgi type 1 neurons
Purkinje cell layer of the gray mater of cerebellum
Composed of granule cells (fibers of which form parallel fibers), neuroglial cells, Golgi cells
Granular layer of the gray matter of cerebellum
connect different regions WITHIN the cerebellum (ex: folium-folium; hemisphere-hemisphere)
Intrinsic fibers of the white matter of cerebellum
form the greater part of the white matter, PROCEED to the cerebellar cortex; enter though the INFERIOR and MIDDLE cerebellar peduncles
Afferent fibers of the white matter of cerebellum
constitute the OUTPUT of the cerebellum; commence as the axons of the Purkinje cells, which synapse with the neurons of the cerebellar nuclei; exit mainly through the SUPERIOR and INFERIOR cerebellar peduncle
Efferent fibers of the white matter of cerebellum
connects to the medulla oblongata; restiform body
Inferior Cerebellar Peduncle
connects to the pons; brachium pontis
Middle cerebellar peduncle
connects to the midbrain; brachium conjunctivum
Superior cerebellar peduncle
“Cerebellar sign par excellence”
Ataxia or dystaxia
lack of synergy of the various muscle components in performing more complex movements so that movements are disjointed and clumsy and broken up into isolated successive parts
Asynergia
Abnormalities in the rate, range and force of movement
Dysmetria
abnormality in the rhythm of rapid alternating movements
Adiodochokinesis; Dysdiadochokinesis
It is related to a depression of gamma and alpha motor neuron activity
Hypotonia
The least evident of the cerebellar abnormalities
Hypotonia
More apparent with acute than with chronic lesion
Hypotonia
Failure to check a movement -a closely related phenomenon (impairment of the check reflex)
Hypotonia
overshooting the target
Hypermetria
A rhythmic tremor of the head or upper trunk (three to four per second)
Titubation
variable intonation (prosody) and abnormalities in articulation; described also as staccato, explosive, hesitant, slow altered accent, and garbled speech
Scanning dysarthria
Speech production is often labored with excessive facial grimacing; Thought to be a result of generalized hypotonia
Cerebellar dysarthria
usually gaze-evoked, upbeat, rebound with abnormal kinetic nystagmus if with midline cerebellar lesions; periodic alternating nystagmus with lesions of the uvula, nodulus; downbeat nystagmus with posterior midline lesions
Nystagmus
Wide-based stance with increased trunk sway, irregular stepping with a tendency to stagger as if intoxicated
Disorders of equilibrium and gait
Kind of cerebellar syndrome that has incoordination of ipsilateral appendicular movements
Hemispheric syndrome
Usual etiologies of this syndrome are infarcts, neoplasms, abscesses
Hemispheric syndrome
Kind of cerebellar syndrome that has a wide-based stance and titubating gait
Rostral vermis syndrome
Kind of cerebellar syndrome that is described to having ataxia of gait & with proportionally little ataxia on the heel-to-shin maneuver with the patient lying down
Rostral vermis syndrome
Kind of cerebellar syndrome that is described to having axial disequilibrium or truncal ataxia and staggering gait
Caudal vermis syndrome
Kind of cerebellar syndrome that is characterized as having little or no limb ataxia ; Sometimes spontaneous nystagmus and rotated postures of the head
Caudal vermis syndrome
Kind of cerebellar syndrome that has bilateral signs of cerebellar dysfunction affecting the trunk, limbs, and cranial musculature
Pancerebellar syndrome
Etiologies of this syndrome are infectious and parainfectious processes, hypoglycemia, hyperthermia, paraneoplastic cerebellar degeneration associated with small cell lung cancer (anti-Hu antibodies), breast and ovarian carcinomas (anti-Yo antibodies), or Hodgkin’s lymphoma (Tr antibodies); Toxic processes
Pancerebellar syndrome
Arises in the posterior part of the vermis and neuroepithelial roof of the fourth ventricle
Medulloblastoma
Arises from the lining in the walls of the ventricles ; 70% originate from the 4th ventricle
Ependymoma and Papilloma of the 4thventricle
May occur anywhere in the neuraxis
Astrocytoma
Occur most often in association with von HippelLindau disease; May have an associated retinal angioma, or hepatic and pancreatic cysts
Hemagioblastoma
Tendency to develop malignant renal or adrenal tumors ; Patients may have polycythemia due to elaboration of erythropoietic factor
Hemangioblastoma
Congenital anomalies at the base of the brain, consisting of: 1.Extension of a tongue of cerebellar tissue into the cervical canal 2.Displacement of the medulla into the cervical canal
Arnold- chiari syndrome
Hydomyelia, syringomyelia are common associated findings
Arnold -Chiari syndrome
Almost always secondary to a purulent focus elsewhere in the body ; 40% are related to diseases of the paranasal sinuses, middle ear, mastoid cells
Brain abcesses
1/3 lie in the anterolateral part of the cerebellar hemisphere;the remainder occur in the middle and inferior parts of the temporal lobe
Brain abcesses
Result from thrombotic or embolic occlusion of a cerebellar vessel
Cerebellar infarction
Prominent signs: limb and gait ataxia, dysarthria, nystagmus, altered mental status
Symptoms: vertigo, dizziness, nausea, vomiting, gait unsteadiness, limb clumsiness, headache, dysarthria, diplopia and decreased level of alertness
Cerebellar infarction
Most common sites of cerebellar hemorrhage
- Putamen and adjacent internal capsule
- Central white matter of temporal, parietal, or frontal lobes
- Thalamus
- Cerebellar hemisphere
- Pons
