Corticokinematic coherence as a new marker for somatosensory afference in newborns

Objective
Somatosensory evoked potentials have high prognostic value in neonatal intensive care, but their recording from infants is challenging. Here, we studied the possibility to elicit cortical responses in newborns by simple passive hand movements.

Methods
We examined 13 newborns (postnatal age 1–46 days) during clinically indicated 19-channel electroencephalography (EEG) recordings in the neonatal intensive care unit; EEG indications included birth asphyxia and suspected epileptic seizures. The experimenter moved the infant’s wrist or fingers at 1 or 2 Hz for 5–10 min, separately on both sides. We measured movement kinematics with an accelerometer attached to the infant’s hand and computed coherence between the EEG and acceleration signals (corticokinematic coherence, CKC).

Results
Statistically significant CKC (amplitude 0.020–0.511) with characteristic scalp topography was observed in all infants at twice the movement frequency. CKC was contralaterally dominant on the central scalp (median laterality index 0.48 for right-hand and −0.63 for left-hand movements).

Conclusions
Passive movements elicit cortical responses that can be readily observed in clinical EEG recordings from newborns in the intensive-care environment.

Significance
CKC is a novel, noninvasive marker for the somatosensory system. Its robustness and practical ease make it attractive for bedside assessment of neurologically compromised newborns.