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Biomedical subjects

Benoit Godey

Publications and source records attributed to Benoit Godey.

5 recordsLinked to original sources

Cochlear size variation in a large-scale international multicentre cohort.

AIM: This study aims to (1) review the literature on cochlear size, measured by the A-value, to assess reported variation across studies, and (2) consolidate cochlear parameters-specifically basal turn diameter (A-value) and width (B-value)-measured using the standardized DICOM viewer OTOPLAN®, and compare these with published data. METHODS: A scoping literature review was conducted using the search term "diameter of cochlear basal turn" to identify studies reporting A-value measurements. To complement this, cochlear measurements obtained with OTOPLAN® were collected from clinical collaborators across multiple international centres. The ratio of B- to A-values, which defines the cochlear basal turn shape, was calculated as previously described by Khurayzi et al. (2021). RESULTS: The literature review identified 38 studies comprising 5,206 A-value measurements (average: 9.08 mm; range: 8.01-10.03 mm). Additionally, 5,580 OTOPLAN® measurements were collected from 43 clinics across 25 countries (mean: 9.07 mm; range: 6.67-11.45 mm). Overall, 68.7% of cochleae exhibited an elliptical basal turn shape. CONCLUSION: Using a large, international multicentre dataset and a standardized measurement tool, this study demonstrates substantial variation in cochlear size and shape across clinical cohorts from different regions. The mean A-value (9.07 mm) is consistent with previously published literature, while the wider observed range highlights greater anatomical variability within a multicentre clinical population than previously reported. The majority of cochleae demonstrate an elliptical basal turn configuration.

Humans↗

Long-term data on children implanted with a short electrode array.

Ossification and cochlear malformations are no longer seen as a contra-indication to cochlear implantation. The MED-EL COMBI 40+ short electrode was designed specifically for cases where major ossification has occurred, or where full insertion of an electrode may not be possible due to abnormal structure of the cochlea. This study investigates outcomes of 18 children implanted with the short electrode array. These children were assessed using the EARS test battery pre-operatively and at a number of intervals thereafter. Results show a consistent improvement in time on most tests; these results appear to be independent of aetiology. Data from these children were compared to 18 matched pairs implanted with the standard COMBI 40+ electrode array. The short electrode children do not perform as well as the standard children initially, but do tend to catch-up at later test intervals. Results indicate the benefit of using a short electrode when complete insertion of the standard electrode is not viable.

Adolescent↗

Functional organization of squirrel monkey primary auditory cortex: responses to frequency-modulation sweeps.

The squirrel monkey twitter call is an exemplar of a broad class of species-specific vocalizations that contain naturally voiced frequency-modulated (FM) sweeps. To investigate how this prominent communication call element is represented in primary auditory cortex (AI), neuronal receptive field properties to pure-tone and synthetic, logarithmically spaced FM-sweep stimuli in 3 barbiturate-anesthetized squirrel monkeys are studied. Responses to pure tones are assessed by using standard measures of frequency response areas, whereas responses to FM sweeps are classified according to direction selectivity, best speed, and speed tuning preferences. Most neuronal clusters respond to FM sweeps in both directions and over a range of FM speeds. Center frequencies calculated from the average of high and low trigger frequency edges of FM response profiles are highly correlated with pure-tone characteristic frequencies (CFs). However, bandwidth estimates are only weakly correlated with their pure-tone counterparts. CF and direction selectivity are negatively correlated. Best speed maps reveal idiosyncratically positioned spatial aggregation of similar values. In contrast, direction selectivity maps show unambiguous spatial organization. Neuronal clusters selective for upward-directed FM sweeps are located in ventral-caudal AI, where CFs range from 0.5 to 1 kHz. Combinations of pure-tone and FM response parameters form 2 significant factors to account for response variations. These results are interpreted in the context of earlier FM investigations and neuronal encoding of dynamic sounds.

Acoustic Stimulation↗

Spatial organization of frequency response areas and rate/level functions in the developing AI.

The current study was conducted to extend our understanding of changes in spatial organization and response properties of cortical neurons in the developing mammalian forebrain. Extracellular multiunit responses to tones were recorded from a dense array of penetrations covering entire isofrequency contours in the primary auditory cortex (AI) of pentobarbital anesthetized kittens. Ages ranged from postnatal day 14 (P14), shortly after acquisition of normal auditory response thresholds, through postnatal day 111 (P111), when the kittens were largely mature. Spatial organization of the AI was tonotopically ordered by P14. The tonotopic gradient decreased with chronological maturation. At P14 the gradient was about 3.5 kHz/mm. By P111 it had declined to about 2.5 kHz/mm, so that the cortical region encompassing a fixed 3- to 15-kHz frequency range enlarged along its posterior-anterior dimension. Response properties of developing AI neurons changed in both frequency selectivity and intensity selectivity. The mean frequency tuning bandwidth increased with age. Initially, tuning bandwidths were narrow throughout the entire AI. With progressive maturation, broader bandwidths were observed in areas dorsal and ventral to a central region in which neurons remained narrowly tuned. The resulting spatial organization of tuning bandwidth was similar to that reported in adult cats. The majority of recording sites manifested nonmonotonic rate/level functions at all ages. However, the proportion of sites with monotonic rate/level functions increased with age. No spatial organization of rate/level functions (monotonic and nonmonotonic) was observed through P111. The relatively late development of bandwidth tuning in the AI compared with the early presence of tonotopic organization suggests that different developmental processes are responsible for structuring these two dimensions of acoustic selectivity.

Acoustic Stimulation↗

Complete cervical tracheal rupture in children after closed trauma.

The authors report the case of a 5-year-old boy who received a blow from a heavy metallic bar on the front of the neck and presented with a complete rupture of the cervical trachea. Such a rupture is exceptional in children because of the consistency of the cartilage but can occur when the neck is in extension and the glottis is closed. A rigid endoscopy allowed the rupture to be diagnosed, to restore the airway, to prepare the cervicotomy, and the suturing of the trachea. He presented with a stenosis 50 days after the suturing which was treated by dilatation.

Amoxicillin↗