Sensory ataxia is both a

symptom Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

and a

sign A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or me ...

in neurology. It is a form of

ataxia Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in e ...

(loss of

coordination Coordination may refer to: * Coordination (linguistics), a compound grammatical construction * Coordination complex, consisting of a central atom or ion and a surrounding array of bound molecules or ions ** A chemical reaction to form a coordinati ...

) caused not by

cerebellar The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or e ...

dysfunction but by loss of sensory input into the control of movement. Sensory ataxia is distinguished from

cerebellar ataxia Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias. Cerebellar ataxia can occur as a result of many diseases and may present with symptoms ...

by the presence of near-normal coordination when the movement is visually observed by the patient, but marked worsening of coordination when the eyes are shut, indicating a positive

Romberg's sign Romberg's test, Romberg's sign, or the Romberg maneuver is a test used in an exam of neurological function for balance. The exam is based on the premise that a person requires at least two of the three following senses to maintain balance whil ...

. Sensory ataxia also lacks the associated features of cerebellar ataxia such as pendular tendon

reflexes In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a Stimulus (physiology), stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous s ...

, scanning

dysarthria Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. It is a condition in which problems effectively occur with the ...

nystagmus Nystagmus is a condition of involuntary (or voluntary, in some cases) Eye movement (sensory), eye movement. People can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in visual impairment, re ...

and broken pursuit eye movements. Patients with sensory ataxia often demonstrate pseudoathetosis and

. They usually complain of loss of balance in the dark, typically when closing their eyes in the shower or removing clothing over the head. __TOC__

Causes

Sensory ataxia can be a manifestation of sensory large fiber peripheral neuropathies and conditions causing dysfunction of the

dorsal columns The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the lo ...

of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

due to a variety of disorders: infectious, auto-immune, metabolic, toxic, vascular and hereditary diseases.

Causes

References

Further reading