What is included in a motor function exam for hypoxic-ischemic encephalopathy (HIE), and what are the typical findings?

Updated: Jul 18, 2018
  • Author: Santina A Zanelli, MD; Chief Editor: Dharmendra J Nimavat, MD, FAAP  more...
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Begin the motor examination of an infant with suspected HIE by qualitatively and quantitatively observing his or her posture and spontaneous movements. Asymmetry in the amount of movement and posture is a subtle sign of hemiparesis, but it may be the only focal feature of the examination. Slight stimulation (eg, gently touching the patient) can increase motor activity in the term neonate and may be helpful in demonstrating asymmetrical hemiparesis.

Eliciting the Moro reflex may be an excessive stimulus and mask a subtle asymmetry in limb movement. Asymmetry in the Moro reflex is seen in peripheral lesions (eg, those due to brachial plexus injury).

Total absence or paucity of spontaneous movements, especially if associated with no reaction to painful stimuli and generalized hypotonia, indicates brainstem dysfunction or severe, diffuse, or multifocal cortical damage.

Specific patterns of motor weakness indicate cerebral injury patterns. Patients with borderzone parasagittal injury (ulegyria) tend to have proximal greater than distal weakness and upper extremity more than lower extremity weakness (man-in-the-barrel). A unilateral, focal infarct, especially one involving the middle cerebral artery, causes contralateral hemiparesis and focal seizures. Patients with selective neuronal necrosis may have severe hypotonia, stupor, and coma.

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