Ataxia

related topics
{disease, patient, cell}
{@card@, make, design}

Ataxia (from Greek α- [used as a negative prefix] + -τάξις [order], meaning "lack of order") is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum. Several possible causes exist for these patterns of neurological dysfunction. The term "dystaxia" is a rarely-used synonym.

The International Ataxia Awareness Day is observed on September 25 each year.[1]

Contents

Types

Cerebellar

The term cerebellar ataxia is employed to indicate ataxia that is due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits, such as antagonist hypotonia, asynergy, dysmetria, dyschronometria, and dysdiadochokinesia. How and where these abnormalities manifest themselves depends on which cerebellar structures have been damaged, and whether the lesion is bilateral or unilateral.

  • Dysfunction of the vestibulocerebellum impairs the balance and the control of eye movements. This presents itself with postural instability, in which the person tends to separate his/her feet upon standing, in order to gain a wider base and to avoid bodily oscillations (especially forward-backward ones). The instability is therefore worsened when standing with the feet together, regardless of whether the eyes are open or closed. This is a negative Romberg's test, or more accurately, it denotes the individual's inability to carry out the test, because the individual feels unstable even with open eyes.
  • Dysfunction of the spinocerebellum presents itself with a wide-based "drunken sailor" gait, characterised by uncertain starts and stops, lateral deviations, and unequal steps. This part of the cerebellum regulates body and limb movements.
  • Dysfunction of the cerebrocerebellum presents with disturbances in carrying out voluntary, planned movements. These include:
    • intention tremor (coarse trembling, accentuated over the execution of voluntary movements, possibly involving the head and eyes as well as the limbs and torso);
    • peculiar writing abnormalities (large, unequal letters, irregular underlining);
    • a peculiar pattern of dysarthria (slurred speech, sometimes characterised by explosive variations in voice intensity despite a regular rhythm).

Full article ▸

related documents
Beta cell
Arteriovenous malformation
Temporal arteritis
Pituitary gland
Erysipelas
Antacid
Motor neuron
Mania
Pulse
Penicillin
Quinolone
Bradycardia
Iridology
Nephrology
Corticosteroid
Central venous catheter
Anandamide
Halothane
Dysentery
Alkaptonuria
Dendrite
Poliomyelitis
Priapism
Median lethal dose
Small intestine
Cardioversion
Larynx
Spleen
Tubal ligation
Large intestine