Pseudoathetosis
Encyclopedia
Pseudoathetosis is abnormal writhing movements, usually of the finger
s, caused by a failure of joint position sense (proprioception
) and indicates disruption of the proprioceptive pathway, from peripheral nerve to parietal cortex.
, however, these abnormal movements are relatively constant irrespective of whether the eyes are open or closed and occur in the absence of proprioceptive loss.
in the cervical spine or lower brainstem (medulla
) respectively.
Finger
A finger is a limb of the human body and a type of digit, an organ of manipulation and sensation found in the hands of humans and other primates....
s, caused by a failure of joint position sense (proprioception
Proprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
) and indicates disruption of the proprioceptive pathway, from peripheral nerve to parietal cortex.
Presentation
Analogous to Romberg's sign, the abnormal posturing is most pronounced when the eyes are closed as visual inputs are unavailable to guide corrective movements. Paradoxically, eye closure may decrease the amount of movement as the visual cues probably trigger corrective movements which return the limb to the desired "baseline" allowing a new phase of involuntary drift before a subsequent corrective phase occurs.Differential diagnosis
It may be mistaken for choreoathetosisChoreoathetosis
Choreoathetosis is the occurrence of involuntary movements in a combination of chorea and athetosis ....
, however, these abnormal movements are relatively constant irrespective of whether the eyes are open or closed and occur in the absence of proprioceptive loss.
Variants
Hemipseudaoathetosis refers to pseudoathetosis on one side of the body ,usually the upper limb and is most commonly caused by a lesion affecting the cuneate tract or cuneate nucleusCuneate nucleus
One of the dorsal column nuclei, the cuneate nucleus is a wedge-shaped nucleus in the closed part of the medulla oblongata. It contains cells that give rise to the cuneate tubercle, visible on the posterior aspect of the medulla...
in the cervical spine or lower brainstem (medulla
Medulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
) respectively.