Functional Near Infra-Red Spectroscopic Study of Central Auditory System Cortical Functional Reorganization (SUN)

Functional Near Infra-Red Spectroscopic Study of Central Auditory System Cortical Functional Reorganization

Functional Near Infra-Red Spectroscopic Study of Central Auditory System Cortical Functional Reorganization in Unilateral Deaf Children

This study aims to compare the auditory cortical activity in response to monaural and binaural stimuli, measured by functional Near-Infrared Spectroscopy (fNIRS) between Single-sided Deaf (SSD) Children, and Normal-Hearing (NH) children from 5 to 16 years. Binaural audiological performance, speech skills and quality of life (QoL) will be compared between the 2 groups and links to with the cortical activity will be assessed.

Binaural hearing allows strengthening of speech intelligibility in noise and sound localization. It is well known that single-sided (SSD) and bilateral asymmetric deafness lead to socio-behavioral consequences and, in children, inducing impairments in learning acquisitions. In adults, SSD is associated with a reduction of inter-hemispheric functional asymmetry of auditory cortex on functional Magnetic Resonance Imaging. Moreover, in children with bilateral profound deafness who got one cochlear implant (inducing a form of asymmetric hearing), these clinical and functional anomalies cannot be overcome in case of a late (>1,5year) secondary implantation. This shows that once the loss of asymmetry is installed, it is difficult to recover from it. No data about SSD in children and its cortical representation exists. In this study, the investigators hypothesized that SSD modifies the auditory cortical activation profile, linked with a deterioration of the binaural auditory skills, the global development and the quality of life If this hypothesis is confirmed, systematic and individualized rehabilitation will be needed to reduce patient's handicap and to prevent long term consequences. The investigators will then measure the auditory cortical activity using fNIRS in 5 to 16 year-old SSD and NH children. The fNIRS system will use a sensor-bearing cap, measuring cortical activity through the scalp. Binaural hearing (speech in noise and localisation), speech assessments (global and speech development), and QoL will also be measured. Children will undergo 2 sessions of 1 to 2 hours tests, each spaced up to 3 months apart. As they are children regularly seen in our ear-nose-throat department, a once-a-year follow-up will be proposed, on the child and his family convenience. As it is a non-interventional study, no follow-up would be needed.

The auditory cortical imaging will be performed by fNIRS measures. This non-invasive functional imaging technique relies on the use of a sensor-bearing cap, measuring cortical activity through scalp, during auditory stimulation. As head movement does not alter measurement that much, fNIRS is well adapted to children.

Speech intelligibility will be evaluated with French sentences comprehension in noise, from the Common Test or Adaptive Auditive Speech Test before 6 years, from the Common Test or Hearing in Noise Test for Children (Hint-C) from 7 to 11 years, and from the Hint-C or Marginal Benefit of Acoustic Amplification after 11 years, both with a Signal over Noise Ratio of +10 decibel at 65 decibel

Sound localisation will be evaluated with a left-right discrimination test before 7 years and a 12 loudspeakers sound localisation test after 7 years.

Speech assessments will be performed by dedicated speech therapists, with child age specific tests, and 2 global speech scores: the Category of Auditory Performances scale - second edition, and the Speech Intelligibility Rating scale.

Quality of Life (QoL) evaluation will be based on the generic QoL scale, and the Speech Spatial and Qualities of hearing (SSQ) deafness specific scale. Each scale exists in age specific modalities.

Oxyhemoglobin (O2Hb) rates measured on the auditory cortex of each cerebral hemisphere during an auditory stimulus.

Deoxyhemoglobin (HHb) rates measured on the auditory cortex of each cerebral hemisphere during an auditory stimulus.

Hearing perception thanks to Category of Auditory Performances - Nottingham Early Assessment Package 4 and speech intelligibility thanks to the Speech Intelligibility Rating - Nottingham Early Assessment Package 5

Quality of Life (QoL) evaluation will be based on the KindLR generic QoL scale. This scale exists in age specific modalities.

Quality of Life (QoL) evaluation will be based on scale, and the Speech Spatial and Qualities of hearing (SSQ) deafness specific scale. This scale exists in age specific modalities.

Inclusion Criteria : For both groups: 5 to 16 year-old children, Absence of pregnancy Affiliation to Social Security, and children and their parents signed consents will be necessary. Participation agreement of the protocol and signature of the consent form by the person having parental authority and the child For Single-sided Deafness subjects: - shall present with moderate to profound unilateral hearing loss, with a hearing loss of 40 decibel(minimal thresholds), assessed on tonal, vocal audiometry, Auditory Brainstem Responses, For Normal hearing subjects: - shall have normal hearing, demonstrated by air thresholds below 20 decibel by an audiometric control before inclusion , matched in gender and age to children in the experimental group Exclusion Criteria: For both groups: Antecedents of Psycho-neurological diseases, Other sensorineural or motor deficiency, Familial bilingualism, Medications affecting vigilance. pregnancy or breastfeeding