الصفحة 1
الصفحة 1
Normal Development of Voice in Children : Advances in Evidence-Based Standards
With updated acoustical measures of voice profiles (phonetograms, the audiogram of the voice) and the fundamental frequency of the tone range, new standards have been reached . In particular, the comparison to normal pediatric and hormonal development highlights the statistical scientific validity of voice parameters. The relation to hormones and the predictive values for voice development open new and interesting perspectives for experts. This book offers valuable insight into acoustical, physiological and biological measures that compare boys and girls and are based on prospective and stratified studies.
Hormones and the brain
Peripheral hormones have a major impact on the brain: they are able to interfere with its development, to affect release of neurotransmitters and concentrations of receptors, to trigger growth factors involved in lesion repair. These multiple actions account for their capacity to modulate a number of physiological parameters, from reproductive functions to memory, behaviour and aging. Depending upon intensity and duration of exposure, they can be either neuroprotective or neurotoxic, for instance by affecting production of free radicals. This book, based on contributions of pioneer investigators in the field, outlines the ambiguous actions of gonadal steroids (estradiol, progesterone, testosterone, inhibin and activin) and of neurosteroids, related moieties produced in the brain itself. After summarizing their multiple mechanisms of action, which involve both direct effects on neuronal membranes and activation of genes coding for specific proteins in neurons or glial cells, the book outlines the role of hormones in pathogenic processes such as mental disturbances or neurodegenerative diseases.
Early puberty in female
Over the past 20 years, a clear secular trend toward the earlier onset of puberty has been described. A better knowledge should help clinicians attempting to define both precocious and delayed puberty. The definition of precocious puberty for girls is the appearance of secondary sex characteristics development before the age of 8 years, while pubertal delay is based on the absence of the larche at the age of 13 years. Regarding precocious puberty, one should clinically distinguish between true precocious puberty, i.e. complete or central precocious puberty, and incomplete precocious puberty, which refers to premature the larche, premature pubarche and isolated menarche...
