In medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

, pronator drift (also known as pyramidal drift) refers to a pathologic sign seen during a neurological examination

Neurological examination

A neurological examination is the assessment of sensory neuron and motor responses, especially reflexes, to determine whether the nervous system is impaired...

. Jean Alexandre Barré

Jean Alexandre Barré

Jean Alexandre Barré , French neurologist, worked in 1916 on the identification of the Guillain-Barré syndrome....

 is credited with having first described it thus it is sometimes known as the Barré test. A positive result indicates spasticity

Spasticity

Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...

. This sign can appear due to an upper motor neuron lesion or various other conditions (including inborn errors of metabolism) which include spasticity as a symptom.

Description

The person is asked to flex the upper limb 90 degrees at the shoulders, supinate his forearms, close his eyes and hold the position. If they are unable to maintain the position the result is positive. Tapping on the palm of the out stretched hands can accentuate the effect.

Interpretation

If a forearm pronates then the person is said to have pronator drift on that side reflecting a contra-lateral pyramidal tract lesion. A lesion in the cerebellum

Cerebellum

The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

produces a drift upwards.

External links

• Picture of pronator drift test position - pediatricneurology.com.