Static ataxia
In the former the ataxia is not influenced by closing the eyes; in the latter (the sensory impulses going up the posterior columns and medial fillet to the thalamus and post central cortex) shutting out visual afferent impulses going to the brain aggravates or brings out the ataxia. From a clinical study or postural body reflexes, I have concluded that the Rom berg sign may on occasion be interpreted as a loss of optic righting reflexes.
Static ataxia is elicited by having the patient touch alternately, slowly and rapidly, the tip of one of his fingers. An ataxic tremor may also become evident. Touching one index finger with another in front of the body, buttoning one’s coat, and touching alternately all the fingers with the thumb, will further bring out the ataxia. At the same time dis symmetric (in ability to measure distance) may be demonstrated, although this can be elicited by asking the patient to raise his arms and bring them quickly to a stop at the horizontal level, requiring correction. Both ataxia and dis symmetric may be brought out by asking the patient to lift a glass of water to his lips. In cerebellar ataxia one frequently observes decomposition of movement; that is instead of carrying out one steady, well time movement with the limb, there is irregularity in the successive flexion or extension at the various joints. May also be demonstrated by having the patient performs rapidly successive antagonistic movement such as probations or sup nation. When positive it is known as in effect it is a disturbance of reciprocal innervations. The rebound phenomenon of Steward and Holmes illustrates the loss of cerebral check or synergy movement: if attempt is made by the examiner to extend the flexed forearm against resistance and him suddenly let’s go the hand or first flies unchecked against the mouth or shoulder.