Hearing loss and brain disorders: A review of multiple pathologies

Several causative factors are associated with hearing loss (HL) and brain disorders. However, there are many unidentified disease modifiers in these conditions. Our study summarised the most common brain disorders associated with HL and highlighted mechanisms of pathologies. We searched the literature for published articles on HL and brain disorders. Alzheimer’s disease/dementia, Parkinson’s disease, cognitive impairment, autism spectrum disorder, ataxia, epilepsy, stroke, and hypoxic-ischaemic encephalopathy majorly co-interact with HL. The estimated incidence rate was 113 per 10,000 person-years. Genetic, epigenetic, early life/neonatal stress, hypoxia, inflammation, nitric oxide infiltration, endoplasmic reticulum stress, and excess glutamate were the distinguished modifiers identified. Various mechanisms like adhesion molecules, transport proteins, hair cell apoptosis, and neurodegeneration have been implicated in these conditions and are serving as potential targets for therapies. To improve the quality of life of patients, these understandings will improve clinical diagnoses and management of HL and brain disorders.

The Hurst Exponent of Heart Rate Variability in Neonatal Stress, Based on a Mean-Reverting Fractional Lévy Stable Motion

We aim at detecting stress in newborns by observing heart rate variability (HRV). The HRV features nonlinearities. Fractal dynamics is a usual way to model them and the Hurst exponent summarizes the fractal information. In our framework, we have observations of short duration, for which usual estimators of the Hurst exponent, like detrended fluctuation analysis (DFA), are not adapted. Moreover, we observe that the Hurst exponent does not vary much between stress and rest phases, but its decomposition in memory and underlying properties of the probability distribution leads to satisfactory diagnostic tools. This decomposition of the Hurst exponent is in addition embedded in a mean-reverting model. The resulting model is a mean-reverting fractional Lévy stable motion (FLSM). We estimate it and use its parameters as diagnostic tools of neonatal stress. Indeed, the value of the speed of reversion parameter is a significant indicator of stress. The evolution of both parameters in which the Hurst exponent is decomposed provides us with significant indicators as well. On the contrary, the Hurst exponent itself does not bear useful information.

Shake It Baby

Every neonate undergoes normal physiologic hypoglycemia within the first few hours of birth given the unique transition between glucose sources. In utero, the mother is the primary source of glucose while, after birth, the newborn slowly transitions to gluconeogenesis, glycogenolysis, and oral feeds to help maintain blood sugar. Though determination of physiologic and pathologic hypoglycemia necessitating treatment may be difficult within the first few hours of life, it is an important one. There are numerous causes of hypoglycemia including maternal diabetes, congenital adrenal hyperplasia, and neonatal stress, among others. It is important to determine the etiology of hypoglycemia, as the prevention of recurrent hypoglycemia is important for neurologic development. Symptoms of hypoglycemia are nonspecific and can be indicative of other disease pathology such as sepsis. Symptoms include high pitched cry, poor suck, lethargy, coma, irritability, and inconsolability, among others. Long-term sequelae for babies with recurrent hypoglycemia and symptomatic hypoglycemia are mainly neurodevelopmental in nature. It is therefore of utmost importance to ensure that proper treatment is initiated to infants necessitating treatment.