Audiology and hearing health professionals in developed and developing countries (2002), Lyn et al. (1998), and Swart et al. (1995), impacted cerumen is one of the most common ear diseases and causes of hearing loss, with prevalence rate between 7.4% and 63%. Additionally, otoscopy does not require a great deal of expertise beyond basic training and is useful to refer a child when the tympanic membrane cannot be visualized due to occlusion of the external auditory meatus by cerumen. Pure-tone audiometry screening, in which there is typically no attempt to find threshold, has been found to accurately assess hearing status in children six years and older, when trained health workers
Substance P concept studies have not yet been persuasively elucidated. Substance P has been associated with the regulation of mood disorders, anxiety, stress, reinforcement, neurogenesis, respiratory rhythm, neurotoxicity, pain, and nociception. In 2014, it was found that substance P played a role in male fruit fly aggression. The vomiting center in the medulla called the Area Postrema, contains high concentrations of substance P and its receptor, in addition to other neurotransmitters such as choline, histamine, dopamine, serotonin, and opioids. Their activation stimulates the vomiting reflex. Different emetic pathways exist, and substance P/NK1R appears to be within the final common pathway to regulate