Incoordination

• Incoordination

  Disruption of spatial accuracy and temporal coordination of movement
• Control Circuits

  • Basal Grangua
  • Mator Cortex
  • Thalamus
  • Cerebellum
• Main arteries supplying the cerebellum

  • Vertebral artery
  • Basillar artery
  • Anterior superior cerebellar artery
  • Antenor inferior cerebellar artery
  • Pastenar inperior cerebellar artery
• Cerebellum requires a lot of O₂ as it is involved in so many functions, so blood flow is very important
• Sections of the cerebellum

  • Antenor Iobe
  • Posterior lobe
  • Floccular Nodular Lobe
  • Lateral part of hemisphere
  • Intermediate part of hemisphere
  • Vermis
• Cerebellum has high density due to its folds
• Feedback and feedforward roles of the cerebellum

  1. Feedforward - plans the movement and says "go"

  2. Feedback - compares actual motor output to intended movement and adjusts as required
• Cerebellar output

  Continuously adapts, develops and changes via mechanisms of synaptic connections
• Damage to the cerebellum

  • Disrupts spatial accuracy and temporal coordination of movement
  • Causes movements to become clumsy and uncoordinated
  • Impairs timing and force production of muscle contractions
  • Causes involuntary movements and tremor
  • Impairs balance and reduces muscle tone
  • Markedly impairs motor learning and some cognitive functions
• General signs and symptoms of cerebellar dysfunction

  • Ataxia
  • Gait ataxia
  • Fear of falling
  • Truncal ataxia
  • Limb ataxia
  • Dysmetria
  • Rebound phenomenon
  • Dysdiadochokinesia
  • Dysarthria-scanning speech
  • Changes in muscle tone, reflexes, nystagmus, writing, head posture, vomiting
• Symptoms of midline cerebellar lesions


  • Midline or equilibratory (gait) ataxia
  • Truncal instability
  • Gait ataxia - wide based, irregular, lateral veering
• Symptoms of flocculonodular lobe lesions

  • Nystagmus
  • Truncal instability
  • Truncal ataxia
  • Vertigo
  • Dizziness and balance issues
  • Vomiting
• Symptoms of cerebellar hemisphere lesions

  • Impaired limb coordination
  • Ataxia of extremities
  • Dysmetria
  • Dysdiodochokinesia
  • Intentional tremor
  • Rebound phenomenon
  • Pendular reflexes
  • Dysarthria
• Other causes of incoordination

  • Sensory dysfunction - loss of proprioception
  • Vestibular dysfunction - vertigo
  • Corticospinal tract - has UMN signs
• Causes of cerebellar disease in childhood

  • Infective - acute viral infection, abscess, CJD
  • Neoplastic - most common place
  • Degenerative - Friedreich's ataxia
  • Congenital - Arnold-Chiari malformation, Dandy-Walker syndrome, metabolic disorders
• Causes of cerebellar disease in adulthood

  • Vascular - infarction, haemorrhage
  • Neoplastic - tumours, metastases
  • Degenerative - demyelination, hereditary disorders
  • Congenital - aqueduct stenosis
  • Metabolic - loss of Purkinje cells
  • Always ask questions in regards to - alcohol, anticonvulsants, myxoedema, vitamin deficiencies
• Distinguishing hemisphere vs lower CNS deficits

  Presence of cortical deficits (mental state, mood, behaviour) and visual field deficits indicates a hemisphere lesion
• General functions of the cerebral hemispheres

  • Corpus callosum allows communication between hemispheres
  • Specific areas may be specialized for certain functions, but location is not always consistent between individuals
• Intracranial disorders


  • Cerebrovascular - haemorrhage, infarction, aneurysm, AVM, haematomas
  • Tumours - benign and malignant
  • Infections
  • Trauma - concussion
• Supratentorial vs posterior fossa lesions

  • Supratentorial lesions are more common in adults, may take time to cause raised ICP
  • Posterior fossa lesions are more common in children, smaller mass likely to cause earlier raised ICP
• Symptoms of raised intracranial pressure

  • Headache
  • Vomiting - worse in mornings, aggravated by stooping/bending
  • Papilloedema - medical emergency
• Symptoms of frontal lobe lesions

  • Loss of drive
  • Apathy
  • Disinhibition
  • Memory problems
  • Diminished intellect
  • Epilepsy
  • Focal motor seizures
  • Adversive eye movements
  • Status epilepticus
  • Weakness opposite side of body
  • Speech disturbance
  • Visual field and acuity changes
  • Grasp reflexes
  • Upper motor neuron signs
• Symptoms of parietal lobe lesions

  • Sensory seizures
  • Soft motor signs
  • Visual pathway disturbance
  • Impaired passive joint movement sense
  • Disturbed touch localisation and 2-point discrimination
  • Disturbed size and texture appreciation
  • Perceptual rivalry
  • Altered optokinetic nystagmus
• Symptoms of right frontal lobe lesions

  • Anosognosia - lack of awareness of opposite side
  • Dyspraxia - loss of acquired skills
• Symptoms of left frontal lobe lesions

  • Confusion of right and left
  • Difficulty distinguishing fingers
  • Disturbance of calculation
  • Disturbance of right-left writing
  • Dysphasia - loss of language production or comprehension
• Symptoms of temporal lobe lesions

  • Epileptic complex partial seizures
  • Complex autonomisms -e.g. Lipping, sucking, kissing, repeated fiddling with clothes
  • Altered consciousness but maintained motor dexterity
  • Prodromes before seizure - visual/auditory hallucinations, visceral sensations, déjà vu
  • Personality change
  • Memory loss
  • Visual pathway disturbance
  • Face and limb weakness
• Symptoms of occipital lobe lesions

  • Seizures with flashing lights/aura
  • Visual field defects
  • Dyslexia
  • Visual agnosia
• Spinocerebellar

  Receives afferent information through spinocerebellar tract = proprioception From trunk and limbs. Give info on balance and equilibrium.
• Where does information from the vermis and fastigial nucleus travel?

  To the medial descending systems
• Where does information from the intermediate part of the hemisphere and the interposed nuclei travel?

  To lateral descending systems
• What is the role of the medial and lateral descending systems?

  Motor execution
• Where does information from the vestibulocerebellum travel to?

  To the vestibular nuclei
• what is the role of the vestibular nuclei?

  Balance and eye movements
• where does information from the lateral hemisphere and dentate nucleus travel to?

  To motor and premotor cortices.
• what is the role of the motor and premotor cortices?

  Motor planning
• what does the lateral hemisphere store?

  motor programmes
• Lingula lesion

  • May extend into superior medullary velum
  • IV nerve palsies
  • Superior cerebellar peduncle - Severe hemiparesis of arm on same side
• Flocculonodular lesion may extend where?

  Floor of 4th ventricle
• What does adversive eyes mean in regards to epilepsy?

  Eyes move more laterally and stay in position for a short while when seizures occur
• what is status epilepticus?

  seizure on top of another = MEDICAL EMERGENCY