Sensory systems hearing

Sensory systems Hearing Hearing loss can occur after the use of opioids. In a retrospective case series review, bilateral rapidly progressive profound sensorineural deafness and macrocytosis were reported in association with codeine in 10 patients [37 ]. All had a history of long-term codeine use and abuse. The authors proposed that the presence of macrocytosis in all the cases suggested a vascular pathology. 

Sensory systems Hearing A 55-year-old man with confirmed murine typhus developed bilateral hearing loss 9 days after the onset of fever and after taking azithromycin 500mg/day for 3 days [75 ]. The authors postulated that the typhus infection had probably caused the deafness but could not exclude an adverse reaction to azithromycin. 

Sensory systems Hearing loss was attributed to high concentrations of gabapentin in a patient with renal insufficiency [117 ]. 

Two ears. Our ability to determine the direction from which a sound is coming is partly based on the difference in time at which our two ears detect the sound. Given the speed of sound (350 meter/second) and the separation between our ears (0.15 meter), what difference is expected in the times at which a sound arrives at our two ears How does this difference compare with the time resolution of the human hearing system Would a sensory system that utilized 7TM receptors and G proteins be capable of adequate time resolution ... 

Energy and information. The transmission of sensory information requires the input of free energy. For each sensory system (olfaction, gustation, vision, hearing, and touch), identify mechanisms for the input of free energy that allow the transmission of sensory information. 

Effects observed in humans following neurotoxic exposure include modification of motor and sensory activities, emotional states, integrative capabilities such as learning and memory, adverse effects on sensory systems (including sight, hearing, smell, touch, and pain sensation), behavior modification, sleep loss, speech impairment, delirium, hallucinations, convulsions, and deaths1-4 ... 

How do our sensory systems work How are the initial stimuli detected How are these initial biochemical events transformed into perceptions and experiences We have already encountered systems that sense and respond to chemical signals—namely, receptors that bind to growth factors and hormones. Our knowledge of these receptors and their associated signal-transduction pathways provides us with concepts and tools for unraveling some of the workings of sensory systems. For example, 7TM receptors (seven-transmembrane receptors. Section 14.1) play key roles in olfaction, taste, and vision. Ion channels that are sensitive to mechanical stress are essential for hearing and touch. 

Smell, taste, vision, hearing, and touch are based on signal-transduction pathways activated by signals from the environment. These sensory systems function similarly to the signal-transduction pathways for many hormones. "These intercellular signaling pathways appear to have been appropriated and modified to process environmental information. 

In this chapter, we shall focus on the five major sensory systems found in human beings and other mammals olfaction (the sense of smell i.e., the detection of small molecules in the air), taste or gustation (the detection of selected organic compounds and ions by the tongue), vision (the detection of light), hearing (the detection of sound, or... 

This chapter will consider methods and devices used to present visual, auditory, and tactual (touch) information to persons with sensory deficits. Sensory atigmentation systems such as eyeglasses and hearing aids enhance the existing capabilities of a functional human sensory system. Sensory substitution is the use of one human sense to receive information normally received by another sense. Braille and speech synthesizers are examples of systems that substitute touch and hearing, respectively, for information that is normally visual (printed or displayed text). 

Sensory systems Acute bilateral sensorineural hearing loss followed methadone overdose (75 mg) in an opioid-naiVe individual there was gradual improvement in hearing over 10 days [89 ]. 

Sensory systems Auditory and vestibular function In 93 patients with acute uncomplicated malaria auditory function was tested before and after a 3-day course of artesunate 4 mg/kg/day combined with mefloquine 25 mg/kg, using tympanometry, audiometry, and auditory brain stem response [26 ]. Hearing loss on day 0 was common (57%) and was associated with age only. However, no patient had a threshold change exceeding 10 decibels between day 0 and day 7 at any tested frequency, and none had a shift in wave III peak latency of more than 0.3 msec between baseline and day 7. Thus, there was no evidence of auditory toxicity in these patients 7 days after a course of artesunate and mefloquine. 

Sensory systems Auditory function Sensorineural hearing loss has been attributed to interferon plus ribavirin [25 ]. 

Sensory systems, ear Six cases of hearing impairment attributed to oral terbinafine intake were reported to the Netherlands Pharmacovigilance Centre Lareb [4 ]. Both male and female were involved and the latency between terbinafine use and hearing impairment was from 2 days to 6 months. Outcomes for two cases were reported and the patients recovered after withdrawal of terbinafine. 

A second difficulty in studying the brain mechanisms of flavor is that the flavor modality is large and ill defined. One can appreciate this by considering other sensory systems. Visual perception is characterized by the specific attributes of a visual stimulus—wavelength, luminance, shape, orientation, motion. Similarly, hearing is characterized by the specific qualities of sound frequency, loudness, and frequency modulation. Touch is characterized by place, quality, and intensity. In all these cases what we may call the sensory space is clearly limited and clearly defined. 

Sensations interpreted as pain, including burning, aching, stinging, and soreness, are the most distinctive forms of sensory input to the central nervous system. Pain serves an important protective function because it causes awareness of actual or potential tissue damage. Furthermore, it stimulates an individual to react to remove or withdraw from the source of the pain. Unlike other forms of sensory input, such as vision, hearing, and smell, pain... 

Hair cells are the sensory cells of the auditory and vestibular systems. Hair cells are the sensory cells of the internal ear, essential for the senses of sound and balance. The hair cell s transduction apparatus, the molecular machinery that converts forces and displacements into electrical responses, can respond to mechanical stimuli of less than 1 nm in amplitude, and of tens or even hundreds of kilohertz in frequency. Indeed, our hearing is ultimately limited by Brownian motion of water molecules impinging on the transduction apparatus. 

The mechanosensory systems of fish, including the lateral line, are closely related to the mammalian hearing system [12]. Besides possessing the typical vertebrate inner ear, fish possess the lateral line organs that contain sensory hair cells. These analogies are most relevant in toxicology and dmg discovery and evaluation, as some of the pharmaceuticals already detected in aquatic ecosystems as emerging pollutants affect the auditory function in humans. 

Toxicity/symptoms nervous system, developmental effects include cerebral palsy-like symptoms with involvement of the visual, sensory, and auditory systems, tingling around lips and mouth, tingling in fingers and toes, vision and hearing loss... 

So it would appear that the brain alertness systems can either be cranked up to a hyperattentive level such that one hears voices and ascribes malevolent intentions to them, or cranked down to so low a level that intrinsic pseudo-sensory signals cause us to see and feel things that we cannot integrate cognitively because our short-term memory capacity is simultaneously disenabled. 

Central nervous system and neuromuscular junction. A remarkable number of alkaloids interfere with the metabolism and activity of neurotransmitters in the brain and nerve cells, a fact known to man for a thousand years (Table IV). The cellular interactions have been discussed above. Disturbance of neurotransmitter metabolism impairs sensory faculties, smell, vision, or hearing, or they may produce euphoric or hallucinogenic effects. 

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