Sensory Ataxia

ATAXIA is a general term used to describe the combined influence of cerebellar and sensory dysfunction on gait, posture, and patterns of movement.

Ataxia due to sensory impairment.

• CAUSES:
• Peripheral nerve: Peripheral neuropathy (especially Diabetic, Alcoholic and Nutritional), Peripheral neuritis.
• Posterior root: Tabes dorsalis.
• Posterior column: Subacute combined degeneration of the cord, Demyelination changes of the posterior column.

MECHANISM/ PATHOPHYSIOLOGY:

Damage to the posterior column -loss of connection between the cerebellum and spinal cord-lack of proprioceptive information-sensory ataxia

CLINICAL PRESENTATION:

KINETIC TREMORS: appear only on the closure of the eyes.

PSUEDOATHETOSIS: random finger movements seen on outstretched hands with eyes closed may occur in sensory neuronopathy affecting the upper limbs.

DEEP SENSORY LOSS- proprioception, kinesthetic awareness, vibration sense

HYPOTONIA

HYPOREFLEXIA

RHOMBERG'S TEST: when the patient stands with his feet close together & his eyes closed, his body sways & he may fall if not supported. The visual system can provide compensation information when the eyes are open, so the patient can remain upright and stable; Visual compensation would disappear when the eyes are closed, and patients will not be able to maintain upright stability.

SENSORY GAIT/HIGH STEPPING GAIT/FEET-SLAPPING GAIT

When a normal person walks, the sensory nerve would be stimulated when the sole touches the ground, then the relevant information is transmitted to indicate the position of the feet. Since the patients with sensory ataxia lose the input of the stimulus, to know the time and place the feet land, the patient would put his feet on the ground heavily. The key to this gait is that when patients can’t see their feet (e.g., in the dark), stepping will increase obviously. This gait is sometimes referred to as a stepping gait, because patients may lift their legs to a very high position.

heavy strike of the ground on walking due to lost deep sensation.

high-stepping gait due to associated motor weakness

feet-slapping gait - to assist with sound-induced sensory feedback. 

REFERENCES: 1. Ashizawa, Tetsuo, and Guangbin Xia. “Ataxia.” Continuum (Minneapolis, Minn.) vol. 22,4 Movement Disorders (2016): 1208-26. doi:10.1212/CON.00000000000003622. Lanska DJ. The Romberg sign and early instruments for measuring postural sway. Semin Neurol. 2002 Dec;22(4):409-18. doi: 10.1055/s-2002-36763. PMID: 12539062. 3. Missaoui, B., et al. "Balance and gait parameters in sensory ataxia; effects of a balance training program." Annals of Physical and Rehabilitation Medicine 56 (2013): e201. 4. Zhang, Qing et al. “Clinical Recognition of Sensory Ataxia and Cerebellar Ataxia.” Frontiers in human neuroscience vol. 15 639871. 1 Apr. 2021, doi:10.3389/fnhum.2021.639871