RESUMEN
This study aimed to compare preterm (PT) and full-term (FT) infants' adaptive behavior and functional cortical response to tactile stimulus, as measured by Test of Sensory Functions in Infants and functional Near-Infrared Spectroscopy (fNIRS). Outcome measures were taken at 6 (PT = 26/FT = 21 infants) and 12 months (PT = 15/FT = 14 infants). At 6 months, poorer tactile reactivity was observed in PT, but not confirmed at 12 months. At 6 months, cortical response to tactile stimulus was found in the primary sensorimotor cortex and differences between groups did not reach significance. At 12 months, cortical response was found in the primary sensorimotor cortex and premotor area and in the somatosensory associative area, with significant less frequent response in premotor area in PT. The findings reinforce fNIRS as a tool to complement the knowledge of tactile adaptive behaviors in PT in early life.
Asunto(s)
Recien Nacido Prematuro , Tacto , Recién Nacido , Humanos , Lactante , Proyectos Piloto , Recien Nacido Prematuro/fisiología , Espectroscopía Infrarroja CortaRESUMEN
Congenital toxoplasmosis (CT) is a known cause of hearing loss directly caused by Toxoplasma gondii. Hearing loss might result from sensory, neural, or sensorineural lesions. Early treated infants rarely develop hearing loss, but retinochoroidal lesions, intracranial calcifications and hydrocephalus are common. In this study, we aimed to evaluate the brain evoked hemodynamic responses of CT and healthy infants during four auditory stimuli: mother infant directed speech, researcher infant directed speech, mother reading and researcher recorded. Children underwent Transitionally Evoked Otoacoustic Emission Auditory Testing and Automated Brainstem Auditory Response tests with normal auditory results, but with a tendency for greater latencies in the CT group compared to the control group. We assessed brain hemodynamics with functional near-infrared spectroscopy (fNIRS) measurements from 61 infants, and we present fNIRS results as frequency maps of activation and deactivation for each stimulus. By evaluating infants in the three first months of life, we observed an individual heterogeneous brain activation pattern in response to all auditory stimuli for both groups. Each channel was activated or deactivated in less than 30% of children for all stimuli. There is a need of prospective studies to evaluate if the neurologic or auditory changes course with compromise of children outcomes.
Asunto(s)
Encéfalo/fisiopatología , Pérdida Auditiva/diagnóstico , Pérdida Auditiva/etiología , Espectroscopía Infrarroja Corta/métodos , Toxoplasmosis Congénita/complicaciones , Estudios de Casos y Controles , Femenino , Pruebas Auditivas , Humanos , Lactante , Recién Nacido , MasculinoRESUMEN
As functional near-infrared spectroscopy (fNIRS) is developed as a neuroimaging technique and becomes an option to study a variety of populations and tasks, the reproducibility of the fNIRS signal is still subject of debate. By performing test-retest protocols over different functional tasks, several studies agree that the fNIRS signal is reproducible over group analysis, but the inter-subject and within-subject reproducibility is poor. The high variability at the first statistical level is often attributed to global systemic physiology. In the present work, we revisited the reproducibility of the fNIRS signal during a finger-tapping task across multiple sessions on the same and different days. We expanded on previous studies by hypothesizing that the lack of spatial information of the optodes contributes to the low reproducibility in fNIRS, and we incorporated a real-time neuronavigation protocol to provide accurate cortical localization of the optodes. Our proposed approach was validated in 10 healthy volunteers, and our results suggest that the addition of neuronavigation can increase the within-subject reproducibility of the fNIRS data, particularly in the region of interest. Unlike traditional approaches to positioning the optodes, in which low intra-subject reproducibility has been found, we were able to obtain consistent and robust activation of the contralateral primary motor cortex at the intra-subject level using a neuronavigation protocol. Overall, our findings support the hypothesis that at least part of the variability in fNIRS cannot be only attributed to global systemic physiology. The use of neuronavigation to guide probe positioning, as proposed in this work, has impacts to longitudinal protocols performed with fNIRS.