L14 Cerebellar Ataxia Flashcards
where does the word cerebellum come from
the latin for “little brain”
what percentage of brain neurons does the cerebellum contain
80%
what is the motor role of the cerebellum
- linked to voluntary motor coordination
- does not initiate muscular activities
- coordinate motor activities initiated elsewhere in the CNS
- partly responsible for motor learning
how does the cerebellum coordinate movement
- Compares expected movement (from motor cortex) with actual movement (proprioceptive feedback).
- Corrects movement errors in real time.
what does voluntary movement in the absence of the cerebellum look like
clumsy and disorganised
does the cerebellum work ipsilaterally or contralaterally
ipsilaterally
does the cerebrum work ipsilaterally or contralaterally
contralaterally
what nonmotor areas does is the cerebellum involved in
- Memory
- Cognition
- Language
- Social behavior (Possible links to Autism Spectrum Disorder (ASD) and schizophrenia).
is cognitive impairment in cerebellar damage mild, moderate or severe
- chronic cerebellar lesions reveal mild cognitive impairment
- impairment may be more prominent in acute cerebellar damage
what is ataxia
lack of coordination caused by cerebellar damage
clinical signs of ataxia
- Finger-nose-finger test (past-pointing): Inability to judge distances.
- Dysdiadochokinesis: Jerky, inaccurate rapid alternating movements.
- Cerebellar rebound.
- Heel-knee-shin test.
causes of ataxia
- inherited
- Identified cause
- Idiopathic
examples of inherited ataxias
- Friedreich’s ataxia
- spinocerebllar ataxias
examples of identified causes on aquired ataxia
- stroke
- tumour
features of cerebellar disorders
- Ataxia.
- Decomposition of movement.
- Dysmetria (inability to judge distances).
- Dysdiadochokinesis (difficulty with rapid alternating movements).
- Rebound phenomenon.
- Hypotonia (reduced muscle tone).
- Tremor.
- Nystagmus (involuntary eye movements).
- Disturbance of posture and gait.
- Ataxic Dysarthria.
- Scanning Speech.
aetiology of cerebellar disorder
- Inherited
- Congenital
- Trauma.
- Infections
- Inflammatory conditions
- Vascular causes
- Neoplastic
- Metabolic
- Toxic/Drug-induced
- Degenerative diseases
example of a congenital cerebellar disorder
Arnold-Chiari Malformation
example of infections causing cerebellar damage
- abscess
- post-viral
example of an inflammatory condition causing cerebellar damage
MS
example of a vascular cause of cerebellar damage
- infarction
- hemorrhage
example of neoplastic causes of cerebellar damage
- paraneoplastic
- metastases
metabolic causes of cerebellar damag e
hypothyroidism
examples of toxic/drug induced causes of cerebellar damage
- alcohol
- phenytoin
example of a degenerative disease causing cerebellar damage
Multiple systems atrophy
what are spino-cerebellar ataxias (SCAs)
- Group of neurodegenerative disorders.
- Typically autosomal dominant inheritance.
how many classified types of SCAs are there
more than 30
what are the most two most common forms of SCA
- SCA3
- SCA6
what is another name for SCA3
Machado-Joseph Disease
onset of SCA3
middle-age onset
what systems does SCA3 affect
- cerebellar
- pyramidal
- extrapyramidal
- autonomic
onset of SCA6
late onset
which systems does SCA6 affect
primarily cerebellar involvement
two subtypes of cerebellar disorders
- midline cerebellar syndromes
- hemispheric cerebellar syndromes
features of midline cerebellar syndromes
- Imbalance/unsteady.
- Unable to stand in Romberg with eyes open or close.
- Trunkal ataxia → syndrome where a person cannot sit on their bed without steadying themselves.
- Titubation → bobbing motion of the head or trunk.
- Nystagmus, ocular dysmetria and poor pursuit.
features of hemispheric cerebellar syndromes
- Incoordination of the limbs.
- Decomposition of movement, dysmetria and rebound.
- Dysdiadochokinesis.
- Intention tremours.
- Finger to nose and heel to knee tests are classic tests of hemispheric cerebellar dysfunction.
- Speech may be dysarthric, scanning or have irregular emphasis on syllables.
how is cerebellar damage diagnosed
- family history
- imaging (MRI)
- genetic testing
what rating scale is used for ataxia
Scale for the Assessment and Rating of Ataxia (SARA)
what are the items on the SARA
- Gate
- Stance
- Sitting
- Speech disturbance
- Finger chase
- Nose-finger test
- Fast alternating hand movements
- Heel-shin slide
subsystems impacted in ataxic dysarthria
- respiration
- phonation
- articulation
- prosody
respiration features of ataxic dysarthria
reduced breath support for speech
phonation features of ataxic dysarthria
harsh voice quality.
articulation features of ataxic dysarthria
- imprecise consonants
- distorted vowels
- poorly coordinated and irregular articulatory movements
- improper formation and separation of individual syllables.
prosody features of ataxic dysarthria
- abnormal stress
- slow rate
- variable pitch
- impaired loudness control
respiration management in ataxic dysarthria
- Speak immediately on exhalation.
- Stop phonation early (before speaking on residual air).
- Determine optimum breath group (how many syllables to speak before taking another breath).
articulation management in ataxic dysarthria
- Intelligibility drills.
- Over-articulation.
- Minimal contrast drills.
prosody (rate) management in ataxic dysarthria
- slow rate.
- Finger or hand tapping to set the pace for syllable production.
- Cued readings (finger pointing or marking pauses).
prosody (intonation and stress) management in ataxic dysarthria
- Contrastive stress drills.
- Intonational drills using printed material with pitch markings.
- Chunking information into syntactic units (using marked inhalation cues in written passages).
swallowing difficulties in cerebellar disease
- Poor oral control of bolus.
- Penetration/aspiration risk.
- Weak cough response.
issues which contribute to swallow difficulties in cerebellar disease
- Poor posture for feeding.
- Impaired feeding ability (due to tremor, dysmetria).
- Poor volume control.
what areas of language might the cerebellum have involvement in
- Verbal fluency.
- Word retrieval.
- Syntax.
- Reading & writing.
- Metalinguistic abilities.
what is Freidrich’s Ataxia
- rare autosomal recessive disorder
- causes progressive ataxia
onset in Friedrich’s ataxia
usually before age 25 (often adolescence)
characteristics of Friedrich’s ataxia
- Ataxic gait.
- Tendon areflexia.
- Upgoing plantar reflexes.
- Skeletal deformities:
- Kyphoscoliosis.
- Pes cavus (high-arched foot deformity).
- Electrocardiographic abnormalities (indicative of cardiomyopathy, common cause of early death).
- Optic atrophy.
- Nystagmus.
- Dysarthria.
- Dysphagia.
prevalence of freidrich’s ataxia
2 per 100,000
progression of freidrich’s ataxia
- Gait difficulties bring the patient to medical attention.
- Ambulation lost within 9-15 years of onset.
treatment for Freidrich’s ataxia
- No cure.
- Symptomatic management.
- Multidisciplinary care (focus on mobility, dysarthria, dysphagia).
- Counseling.
