Sensory ataxia
Encyclopedia
Sensory ataxia is both a symptom
and a sign
in neurology. It is a form of ataxia
(loss of coordination) caused not by cerebellar
dysfunction but by loss of sensory input into the control of movement.
Sensory ataxia is distinguished from cerebellar ataxia
by the presence of near-normal coordination when the movement in question is visually observed by the patient, but marked worsening of coordination when the eyes are closed.
Sensory ataxia also lacks the associated features of cerebellar ataxia such as pendular tendon reflexes, scanning dysarthria
, nystagmus and broken pursuit eye movements.
Patients with sensory ataxia often demonstrate pseudoathetosis
and Romberg's sign. They usually complain of loss of balance in the dark, typically when closing their eyes in the shower or removing clothing over the head.
such as tabes dorsalis
.
The cause can also be genetic.
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
and a sign
Medical sign
A medical sign is an objective indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....
in neurology. It is a form of ataxia
Ataxia
Ataxia 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...
(loss of coordination) caused not by cerebellar
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
dysfunction but by loss of sensory input into the control of movement.
Sensory ataxia is distinguished from cerebellar ataxia
Ataxia
Ataxia 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...
by the presence of near-normal coordination when the movement in question is visually observed by the patient, but marked worsening of coordination when the eyes are closed.
Sensory ataxia also lacks the associated features of cerebellar ataxia such as pendular tendon reflexes, scanning dysarthria
Dysarthria
Dysarthria is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech system and is characterized by poor articulation of phonemes...
, nystagmus and broken pursuit eye movements.
Patients with sensory ataxia often demonstrate pseudoathetosis
Pseudoathetosis
Pseudoathetosis is abnormal writhing movements, usually of the fingers, caused by a failure of joint position sense and indicates disruption of the proprioceptive pathway, from peripheral nerve to parietal cortex.-Presentation:...
and Romberg's sign. They usually complain of loss of balance in the dark, typically when closing their eyes in the shower or removing clothing over the head.
Causes
Sensory ataxia is present in sensory peripheral neuropathies and conditions causing dysfunction of the dorsal columns of the spinal cordSpinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
such as tabes dorsalis
Tabes dorsalis
Tabes dorsalis is a slow degeneration of the sensory neurons that carry afferent information. The degenerating nerves are in the dorsal columns of the spinal cord and carry information that help maintain a person's sense of position , vibration, and discriminative touch.-Cause:Tabes dorsalis is...
.
The cause can also be genetic.