dysmetria

Dysmetria (Greek: "difficult to measure") is a difficulty in accurately performing intentional movements. It is exhibited by patients after cerebellar injury or injury to proprioceptive nerves (nerves that carry information about the position of joints and extremities).

More specifically, the term "hypermetria" can be used to describe the overshoot, and "hypometria" can be used to describe the undershoot.^[1]

Mechanism

One of the functions of the cerebellum is to integrate position of the limbs with movement intention, resulting in a necessary constant fine-tuning of movements. A person exhibiting dysmetria is unable to make such adjustments and has difficulty with many manual tasks.

Causes

An upper motor lesion may cause dysmetria. Dysmetria may also be caused by lesions to the Cerebrocerebellum (Neocerebellum); the hemispheres of the Cerebellum. These lesions cause changes in rate, rhythm, force of movement and fine coordination. It is often part of limb ataxia, or dyssynergia, along with dysdiadochokinesia (the inability to perform rapid alternating movements, such as winding up a watch).

See also

• Intention tremor
• Ocular dysmetria

References

1. ^ Manto MU, Jacquy J, Legros B, Bosse P (2002). "Shift from hypermetria to hypometria in multiple system atrophy: analysis of distal and proximal movements". Neurol. Res. 24 (3): 249-58. PMID 11958418. 

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