Hearing brain evaluated using near-infrared spectroscopy in congenital toxoplasmosis

Abstract

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.

Optical imaging and spectroscopy for the study of the human brain: status report

“…A common variant of the two-level model is to count the frequency of a particular response (or any other feature) observed across volunteers in the first level (i.e., within-subject), which is essentially a change of variables to the traditional approach. 132 , 251 – 253 This approach is mainly valuable for summarizing group responses when the inter-subject variability is high, such as in infants. 251 – 253 …”

“… 132 , 251 – 253 This approach is mainly valuable for summarizing group responses when the inter-subject variability is high, such as in infants. 251 – 253 …”

“…A common variant of the two-level model is to count the frequency of a particular response (or any other feature) observed across volunteers in the first level (i.e., within-subject), which is essentially a change of variables to the traditional approach. 132,[251][252][253] This approach is mainly valuable for summarizing group responses when the inter-subject variability is high, such as in infants. [251][252][253] The field is now exploring naturalistic settings that inherently introduce many confounding factors often not present in lab-controlled environments (e.g., the presence of distractors and additional extra-experimental stimuli).…”

“…132,[251][252][253] This approach is mainly valuable for summarizing group responses when the inter-subject variability is high, such as in infants. [251][252][253] The field is now exploring naturalistic settings that inherently introduce many confounding factors often not present in lab-controlled environments (e.g., the presence of distractors and additional extra-experimental stimuli). The demand for models dealing with large numbers of confounders propitiates the emergence of alternatives to classical regression, where modeling of the confounders is implicit.…”