Pseudoathetosis is abnormal writhing movements, usually of the

finger A finger is a prominent digit (anatomy), digit on the forelimbs of most tetrapod vertebrate animals, especially those with prehensile extremities (i.e. hands) such as humans and other primates. Most tetrapods have five digits (dactyly, pentadact ...

s, caused by a failure of joint position sense (

proprioception Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

) and indicates disruption of the proprioceptive pathway, from

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

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 informa ...

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. The exam is based on the premise that a person requires at least two of the three following senses to maintain balance whil ...

, 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 Cuneate means "wedge-shaped", and can apply to: * Cuneate leaf, a leaf shape * Cuneate nucleus, a part of the brainstem * Cuneate fasciculus Cuneate means "wedge-shaped", and can apply to: * Cuneate leaf, a leaf shape * Cuneate nucleus The ...

cuneate nucleus The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the l ...

in the

cervical spine In tetrapods, cervical vertebrae (: 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 sauro ...

or lower

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

(

medulla Medulla (Latin for "marrow") 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 ...

) 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 disease ...

; 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 ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

loss.

References

External links

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