Palmomental reflex

Palmomental reflex

The palmomental reflex (PMR) is an example of a primitive reflex. As such it is present in infancy, disappears during maturation of the brain during childhood but may reappear due to processes that disrupt the normal cortical inhibitory pathways.

Marinesco and Radivici in their seminal paper hypothesize that both the afferent (receptive) and efferent (motor) arms of the reflex are on the same side (ipsilateral) to the hand stimulated; [cite journal|author=Marinesco G, Radovici A|title=Sur un reflexe cutane nouveau: reflexe palmo-mentonnier|journal=Rev Neurol|year=1920|volume=27|pages=237–40] however this hypothesis remains unsubstantiated.cite journal |author=Owen G, Mulley GP |title=The palmomental reflex: a useful clinical sign? |journal=J. Neurol. Neurosurg. Psychiatr. |volume=73 |issue=2 |pages=113–5 |year=2002 |pmid=12122165 |doi=]

The PMR has been found to be present more frequently in various neurological conditions both localized and diffuse. These include congenital conditions such as Down's syndrome where it is unclear whether the reflex persists throughout life or disappears and then re-appears in association with the onset of Alzheimer's disease pathology. The reflex is common in the elderly population and should not be taken as indicative of a dementing process.cite journal |author=Owen G, Mulley GP |title=The palmomental reflex: a useful clinical sign? |journal=J. Neurol. Neurosurg. Psychiatr. |volume=73 |issue=2 |pages=113–5 |year=2002 |pmid=12122165 |doi=]

Eliciting and Observing response

The thenar eminence is stroked briskly with a thin stick, from proximal(edge of wrist) to distal (base of thumb) using moderate pressure. A positive response is considered if there is a single visible twitch of the ipsilateral mentalis muscle (chin muscle on the same side as the hand tested).

Localizing value

A study set in a neurosurgical in-patient population showed there is no significant association between the side of the reflex and the side of the hemispheric lesion in patients with unilateral (one-sided) reflexes and unilateral (one-sided) lesions.cite journal |author=Gotkine M, Haggiag S, Abramsky O, Biran I |title=Lack of hemispheric localizing value of the palmomental reflex |journal=Neurology |volume=64 |issue=9 |pages=1656 |year=2005 |pmid=15883341 |doi=10.1212/01.WNL.0000160525.50482.C7]
Primitive reflexes such as the PMR were classically viewed as signs of disorders that affect the frontal lobes, however this traditional view is questionable as the reflex has been noted for example in cases of one-sided temporal lobe pathology.

References

External links

[http://www.asktheneurologist.com/primitive-reflexes.html Eliciting and observing the palmomental reflex (video)]


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Reflex — A reaction that is involuntary. The corneal reflex is the blink that occurs with irritation of the eye. The nasal reflex is a sneeze. * * * 1. An involuntary reaction in response to a stimulus applied to the periphery and transmitted to the… …   Medical dictionary

  • palm-chin reflex — palmomental reflex twitching of the chin produced by stimulating (scratching) the palm; called also Marinesco Radovici r. and Radovici sign …   Medical dictionary

  • Snout reflex — The Snout reflex is a pouting or pursing of the lips that is elicited by light tapping of the closed lips near the midline. The contraction of the muscles causes the mouth to resemble a snout.This reflex is tested in a neurological exam and if… …   Wikipedia

  • Palmomentaler Reflex — Der Palmomentalreflex (Syn. Radovici Zeichen) ist ein Reflex, der sowohl bei gesunden, als auch bei Patienten mit einer neurologischen Erkrankung auftreten kann. Der diagnostische Wert ist umstritten. Er wird durch kräftiges Bestreichen der… …   Deutsch Wikipedia

  • Frontal release sign — Frontal release signs are primitive reflexes traditionally held to be a sign of disorders that affect the frontal lobes. The appearance of such signs reflects the area of brain dysfunction rather than a specific disorder which may be diffuse such …   Wikipedia

  • Primitive reflexes — are reflex actions originating in the central nervous system that are exhibited by normal infants but not neurologically intact adults, in response to particular stimuli. These reflexes disappear or are inhibited by the frontal lobes as a child… …   Wikipedia

  • List of anatomical topics — This page aims to list articles related to anatomy. This list is not necessarily complete or up to date if you see an article that should be here but isn t (or one that shouldn t be here but is), please update the page accordingly. NOTOC A… …   Wikipedia

  • Frontotemporal dementia — Infobox Disease Name = PAGENAME Caption = A human brain showing frontotemporal lobar degeneration causing frontotemporal dementia. DiseasesDB = 10034 ICD10 = ICD9 = ICD9|331.19 ICDO = OMIM = 600274 MedlinePlus = eMedicineSubj = eMedicineTopic =… …   Wikipedia

  • Thenar eminence — Infobox Muscle Name = PAGENAME Latin = eminentia thenaris GraySubject = 126 GrayPage = 546 Caption = The mucous sheaths of the tendons on the front of the wrist and digits. Caption2 = Transverse section across the wrist and digits. (Muscles of… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”