Spatiotemporal organization of myoclonic twitching in sleeping human infants

Abstract

During the perinatal period in mammals when active sleep predominates, skeletal muscles twitch throughout the body. We have hypothesized that myoclonic twitches provide unique insight into the functional status of the human infant's nervous system. However, assessments of the rate and patterning of twitching have largely been restricted to infant rodents. Thus, here we analyze twitching in human infants over the first seven postnatal months. Using videography and behavioral measures of twitching during bouts of daytime sleep, we find at all ages that twitching across the body occurs predominantly in bursts at intervals of 10 s or less. We also find that twitching is expressed differentially across the body and with age. For example, twitching of the face and head is most prevalent shortly after birth and decreases over the first several months. In addition, twitching of the hands and feet occurs at a consistently higher rate than does twitching elsewhere in the body. Finally, the patterning of twitching becomes more structured with age, with twitches of the left and right hands and feet exhibiting the strongest coupling. Altogether, these findings support the notion that twitches can provide a unique source of information about typical and atypical sensorimotor development.

Twitches emerge postnatally during quiet sleep in human infants and are synchronized with sleep spindles

“…Twitches were coded using methods developed and described previously (1). Two coders independently coded 100% of the video records for twitches.…”

“…Inter-observer reliability was assessed as described previously (1). Briefly, we determined the time of occurrence of twitches detected by the two coders across all movement categories, applying a 0.5 s duration to each twitch.…”

“…In humans and other mammals, the stillness of sleep is punctuated by bursts of rapid eye movements (REMs) and myoclonic twitches of the limbs (1). Contrary to the common notion that twitches are mere by-products of dreams, sensory feedback arising from twitching limbs provides a rich and unique source of activation to the developing sensorimotor system (2).…”

“…We recorded infants' sleep during the daytime in the laboratory. In all sessions, infants slept in a supine, semi-reclined position, as described previously (8). Infants were fitted with a high-density electrode cap for measurement of EEG and movements were recorded using a video camera from a frontal view.…”

Long-range temporal organisation of limb movement kinematics in human neonates

“…unilateral progressing to bilateral), predicts positive sensorimotor outcomes ( Prechtl et al, 1997 , Einspieler et al, 2008 ). Recent work has demonstrated temporal-spatial organisation at the level of seconds for isolated limb movements also ( Sokoloff et al, 2020 ). However, the macro -organisation of the full repertoire of neonatal motor activity, at the level of many minutes to hours, is unknown.…”