Pseudoathetosis is abnormal writhing movements, usually of the

finger A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...

s, caused by a failure of joint position sense (

proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...

) and indicates disruption of the proprioceptive pathway, from nerve to

parietal cortex The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory inform ...

Presentation

Analogous to

Romberg's sign Romberg's test, Romberg's sign, or the Romberg maneuver is a test used in an exam of neurological function for balance, and also as a test for driving under the influence of an intoxicant. The exam is based on the premise that a person requires ...

, 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.

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 nucleus In neuroanatomy, the dorsal column nuclei are a pair of nuclei in the dorsal columns in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are present at the bottom of the medulla oblongata. Both nucl ...

in the

cervical spine In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sau ...

or lower brainstem (

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of t ...

) respectively.

Diagnosis

Differential diagnosis

It may be mistaken for

choreoathetosis Choreoathetosis is the occurrence of involuntary movements in a combination of chorea (irregular migrating contractions) and athetosis (twisting and writhing). It is caused by many different diseases and agents. It is a symptom of several diseases ...

; but these abnormal movements are relatively constant irrespective of whether the eyes are open or closed, and they occur in the absence of

proprioceptive Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...

loss.

References

External links

{{Medical resources , DiseasesDB = 30711 , ICD10 = , ICD9 = , ICDO = , OMIM = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = , SNOMED CT = 299952008 Medical signs