Neurosensory Hearing Impairment Research Articles

General anesthesia influence on cochlear implant intraoperative testing

In this article, we consider the influence of combined general anesthesia on the results of electrically-involved stapedial reflex threshold (esrt) registration. We pay a special attention to the anesthesia to exclude its influence on the esrt. This study included 52 patients with bilateral chronic neurosensory hearing impairment. We conducted a retrospective (from 2014 to 2016) and prospective (from 2017 to 2018) analysis of anesthesia protocols. Even though the inhaled anesthesia (sevoflurane in this case) has a depressive effect on esrt registration (the higher the minimal alveolar concentration of anesthetic agent, the higher the reflex threshold), our study shows a possibility of using it in an extended anesthesia monitoring. Inclusion of myorelaxants in cochlear implantation anesthesia protocol not only provides a safe anesthesia, but also does not prevent a timely intraoperative cochlear implant testing.

Use of nouns and verbs in the oral narrative of individuals with hearing impairment and normal hearing between 5 and 11 years of age.

Nouns and verbs indicate actions in oral communication. However, hearing impairment can compromise the acquisition of oral language to such an extent that appropriate use of these can be challenging. The objective of this study was to compare the use of nouns and verbs in the oral narrative of hearing-impaired and hearing children. Analytical cross-sectional study at the Department of Speech-Language and Hearing Sciences, Universidade Federal de São Paulo. Twenty-one children with moderate to profound bilateral neurosensory hearing impairment and twenty-one with normal hearing (controls) were matched according to sex, school year and school type. A board showing pictures was presented to each child, to elicit a narrative and measure their performance in producing nouns and verbs. Twenty-two (52.4%) of the subjects were males. The mean age was 8 years (standard deviation, SD = 1.5). Comparing averages between the groups of boys and girls, we did not find any significant difference in their use of nouns, but among verbs, there was a significant difference regarding use of the imperative (P = 0.041): more frequent among boys (mean = 2.91). There was no significant difference in the use of nouns and verbs between deaf children and hearers, in relation to school type. Regarding use of the indicative, there was a nearly significant trend (P = 0.058). Among oralized hearing-impaired children who underwent speech therapy, their performance regarding verbs and noun use was similar to that of their hearing counterparts.

Maternally-inherited diabetes with deafness (MIDD) and hyporeninemic hypoaldosteronism

Maternally-inherited diabetes with deafness (MIDD) is a rare form of monogenic diabetes that results, in most cases, from an A-to-G transition at position 3243 of mitochondrial DNA (m.3243A>G) in the mitochondrial-encoded tRNA leucine (UUA/G) gene. As the name suggests, this condition is characterized by maternally-inherited diabetes and bilateral neurosensory hearing impairment. A characteristic of mitochondrial cytopathies is the progressive multisystemic involvement with the development of more symptoms during the course of the disease. We report here the case of a patient with MIDD who developed hyporeninemic hypoaldosteronism.

Prenatal diagnosis and prenatal imaging features of fetal monosomy 1p36

Deletion of the distal end of the short arm of chromosome 1 (1p36) is thought to be a common terminal chromosomal deletion. However, few cases prospectively diagnosed prenatally have been reported. In this case, prenatal ultrasound at 21 weeks of gestation noted the fetus to have mild ventriculomegaly (Vhanterior = 11 mm and Vhposterior = 12 mm) and increased nuchal edema (6 mm). Maternal serum alpha-fetoprotein was normal unlike in a majority of previously described cases. The prenatal ultrasound features were further clarified with fetal MRI. Chromosome analysis following amniocentesis demonstrated a 1p36 deletion, which was confirmed by fluorescence in situ hybridization (FISH). The syndrome associated with 1p36 deletion is well described in infants and is characterized by typical facial features (prominent forehead, straight eyebrows. deep-set eyes, flat nasal bridge and a pointed chin). Other associated features are neurodevelopmental delay, seizures, cardiomyopathy and neurosensory hearing impairment. This case supplements our knowledge of the prenatal features of 1p36. Identification of this deletion by direct chromosomal analysis can be technically difficult and vigilance is required to improve diagnosis. FISH analysis is an important diagnostic adjunct where the diagnosis is suspected following classical G-banding techniques. However, in this chromosomal anomaly there remain few characteristic prenatal signs that are readily diagnosed with prenatal imaging.

Genetic analysis of GJB2 in a Chinese family with nonsyndromic hearing impairment

Nonsyndromic neurosensory hearing impairment (NSHI) is the most common human sensory disorder. Approximately one in a thousand children is born with prelingual hearing loss. Mutations of the GJB2 gene, which encodes Connexin 26, are the most common cause of hereditary NSHI in many ethnic populations, and are responsible for 50% of cases of autosomal recessive NSHI. In this study, we recruited a complex NSHI pedigree from Jiangsu province of China. Linkage analysis of microsatellite markers flanking all known arNSHI genes linked the causative gene in the family to the polymorphic macrosatellite marker D13S175. Direct DNA sequencing of the whole coding region of GJB2 revealed that a common homozygous mutation 235delC was responsible for most of the affected members in the NSHI family.

Monogenic forms of obesity and diabetes mellitus.

Great progress has been made in identifying several genes and in understanding the molecular pathogenesis of inherited syndromes of obesity and diabetes mellitus (DM). In humans, mutations in leptin, leptin receptor, proopiomelanocortin (POMC), melanocortin-4 receptor (MC4R) and prohormone convertase 1 (PC1) have been described in patients with severe obesity. Most of these obesity disorders, with the exception of the MC4R mutations, exhibit recessive inheritance and a distinct phenotype with varying degrees of hypothalamic dysfunction, and they unravel the critical role of the central leptin and melanocortin pathways in human appetite control and energy homeostasis. Maturity onset diabetes of the young (MODY) is a genetically and clinically heterogeneous subtype of type 2 DM with early onset autosomal dominant inheritance and a primary defect in insulin secretion. To date, six MODY genes have been identified, the glucokinase gene and five beta cell-specific transcription factor genes, hepatocyte nuclear factor-1alpha (HNF-1alpha), HNF-1beta, HNF-4alpha, insulin promoter factor-1 (IPF-1) and NeuroD1/BETA2. Mitochondrial DNA mutations cause another form of DM with an insulin secretory defect that is commonly associated with neurosensory hearing impairment, and has strict maternal inheritance. At the other end of the spectrum are the inherited syndromes of insulin resistance that are caused by mutations in the insulin receptor gene and in the adipocyte-specific transcription factor PPARgamma. The advances in our knowledge of the phenotypic manifestations and underlying molecular mechanisms of genetic syndromes of obesity and DM raise expectations for molecular diagnosis, as well as for more etiological therapies and better prevention of the continuously increasing prevalence of obesity and DM in our modern societies.

Mapping recessive ophthalmic diseases: Linkage of the locus for Usher syndrome type II to a DNA marker on chromosome 1q

Usher syndrome is a heterogeneous group of autosomal recessive disorders that combines variably severe congenital neurosensory hearing impairment with progressive nightblindness and visual loss similar to that in retinitis pigmentosa. Usher syndrome type I is distinguished by profound congenital (preverbal) deafness and retinal disease with onset in the first decade of life. Usher syndrome type II is characterized by partial hearing impairment and retinal dystrophy that occurs in late adolescence or early adulthood. The chromosomal assignment and the regional localization of the genetic mutation(s) causing the Usher syndromes are unknown. We analyzed a panel of polymorphic genomic markers for linkage to the disease gene among six families with Usher syndrome type I and 22 families with Usher syndrome type II. Significant linkage was established between Usher syndrome type II and the DNA marker locus THH33 (D1S81), which maps to chromosome 1q. The most likely location of the disease gene is at a map distance of 9 cM from THH33 (lod score 6.5). The same marker failed to show linkage in families segregating an allele for Usher syndrome type I. These data confirm the provisional assignment of the locus for Usher syndrome type II to the distal end of chromosome 1q and demonstrate that the clinical heterogeneity between Usher types I and II is caused by mutational events at different genetic loci. Regional localization has the potential to improve carrier detection and to provide antenatal diagnosis in families at risk for the disease.