Romberg's sign: swaying of the body or falling when a patient's eyes are closed while standing with the feet close together; observed in tabes dorsalis.
It is a neurological test of joint position sense (proprioception), positive in patients with sensory ataxia. More properly it is a test for loss of position sense (proprioception and semi-circular canals in the middle ear) or sensory ataxia in the legs, and
not a test for cerebellar ataxia.
Romberg's sign is said to be positive in patients with sensory ataxia and negative in cerebellar ataxia. In practise Romberg's sign has a low specificity.
Cerebellar ataxia is a disorder of coordination due to a lesion that affects the cerebellum.
Symptoms
- Disturbance of gait is the commonest presenting feature. The patient may be unable to walk in a straight line or bump into things and it is often worse in the dark.
- Clumsiness carrying objects often precedes deterioration of handwriting. Midline lesions tend to cause problems of gait whilst lesions of the hemispheres cause ipsilateral incoordination.
- Dysarthria is staccato in nature.
- Vomiting or headache suggests a posterior fossa mass. An acute history suggests a cerebellar haemorrhage but a slower onset suggests a tumour or abscess. Vertigo is less common in the degenerative diseases.
Signs
- The patient may enter the room with a broad-based gait. A tandem walk (heel to toe) will demonstrate the problem. About 40% of patients with vermis lesions do not have limb ataxia but disturbance of gait.
- Limb ataxia can be demonstrated by getting the patient to touch his nose then your finger about 40cms away and repeated. An intention tremor overshoots or undershoots the target. Dysdiadochokinesis is demonstrated by getting the patient to tap the back of his hand rapidly or to pronate and supinate the hand rapidly.
- Nystagmus is demonstrated by holding the patient's head still and getting him to follow your finger, about 50cms away, to left and right without going too far to the extreme. The eyes drift slowly back to the centre followed by a rapid correction. Acute or subacute presentation with disordered eye movements should lead to suspicion of Wernicke's encephalopathy and requires urgent treatment with thiamine.
- Cerebellar dysfunction in an infant is easily overlooked. Intrauterine insults may not present with incoordination until the second year of life.
- An intention tremor occurs only on movement unlike the fine tremor at rest in essential tremor or thyrotoxicosis or the pill-rolling of Parkinson's disease.
Cerebellum is involved in the coordination of voluntary motor movement, balance and equilibrium and muscle tone.
Damage to the cerebellum can lead to:
- loss of coordination of motor movement (asynergia)
- the inability to judge distance and when to stop (dysmetria)
- the inability to perform rapid alternating movements (adiadochokinesia)
- movement tremors (intention tremor)
- staggering, wide based walking (ataxic gait)
- tendency toward falling
- weak muscles (hypotonia)
- slurred speech (ataxic dysarthria)
- abnormal eye movements (nystagmus)
Linear Mode
