Hemodynamic response to visual stimulation in newborn infants using functional near‐infrared spectroscopy

Abstract

Brain activity is associated with physiological changes, which alter the optical properties of tissue. These changes can be detected by near-infrared spectroscopy (NIRS). Aim of the study was to determine changes in cerebral oxygenation in response to stimulation in the visual cortex in newborn infants during spontaneous sleep in the first days of life. We used an in-house developed multichannel NIRS imaging instrument, the MCP-II, to measure changes in concentration of oxyhemoglobin (O(2)Hb) and deoxyhemoglobin (HHb) in specific brain areas. In 10 out of 15 subjects, a significant increase in O(2)Hb and/or a significant decrease in HHb were found in one or more channels over the occipital cortex. During stimulation, O(2)Hb increased by a mean of 0.98 mumol/l, HHb decreased by a mean 0.17 mumol/l, and total-Hb increased by a mean of 0.81 mumol/l. The hemodynamic response to visual stimulation in the occipital cortex in newborn infants is similar to adults. The increase in O(2)Hb and the simultaneous decrease in HHb during stimulation suggest an increase in cerebral blood flow (CBF) that overcompensates for the increased oxygen consumption (CMRO(2)) in the activated cortical area.

Precision of cerebral oxygenation and hemoglobin concentration measurements in neonates measured by near-infrared spectroscopy

“…6,7 There is even the possibility to perform functional brain activity measurements. 16 In a clinical setting, for NIRS devices it is important to feature a sufficient precision allowing distinguishing normal from pathological conditions. There are several NIRS devices commercially available based on different technologies, with individual strengths and limitations.…”

Near infrared spectroscopy to study the brain: an overview

“…A typical examples of an ensemble average is displayed in Fig. 3 [68]. In contrast to the findings in adults, the HHb concentration increases in the majority of the infants (90% in Ref.…”

“…There are few reports in the literature on hemodynamic effects in neonates, visual cortex [66][67][68], auditory cortex [69][70][71][72], speech frontal cortex [73], olfactory stimulation [74,75], pain [76][77][78], and motor cortex [14]. Bartocci's [75] findings during the presentation of unpleasant smells to infants are highly particular, because a decrease in O 2 Hb concentration was observed, while the HHb concentration remained approximately constant.…”

“…Optical imaging techniques in neonates clearly demonstrate a diagnostic potential [68,69,72,[80][81][82][83], while optical tomography [14], although promising and fascinating, still needs development.…”

Functional Lateralization of Sensorimotor Cortex in Infants Measured Using Multichannel Near-Infrared Spectroscopy

“…In newborn infants, NIRS has been used to assess the activities of the visual cortex (8 -10), frontal cortex (11), temporal cortex (7,12), and olfactory cortex (13) after repeated light simulation, music stimulation, verbal stimulation, and odor stimulation, respectively. Especially, NIRS has been used to mainly asses the activation of the visual cortex induced by checkerboard or flashlight stimulation in awake (8,14) and sleeping (9,10,(15)(16)(17) and at different ages ranging from 32 wk of gestation to 4 mo. However, only a few studies have been conducted on the somatosensory cortex in infants under passive motor stimulation (1,2).…”