Sensor Technology: Function, Tasks, Role & Diseases

In the medical field, the term sensory encompasses the totality of processes involved in sensory perception. Sensory perceptions include vision, hearing, taste, smell, and the sense of balance.

What is sensory perception?

In the medical field, the term sensory encompasses all the processes involved in sensory perception, such as smelling. Sensory science deals with the perception of stimuli from the sensory organs. The sensory organs in humans include the eye, the ear, the nose and the tongue. The ear accommodates two sensory organs. One is the vestibular organ, which is responsible for the sense of balance, and the other is the cochlea, the seat of the sense of hearing. The skin also belongs to the classical sense organs. However, the sense of touch is no longer part of the sensory system. It is assigned to the sensory stimuli. The entirety of the areas in the brain responsible for sensory perception is called the sensory projection centers. All sensory organs including the neurons responsible for stimulus transmission and processing are also called sensorium.

Function and task

The basic sensory process is very similar for all sensory organs. The sensory organ perceives a specific stimulus. This is then transmitted by various nerves either to the sensory brain area or to other structures of the central nervous system (CNS). The actual sensory impression is then produced there. This is also referred to as the primary sensory impression. In a second step, the primary impression is compared with data stored in the brain. This process is also called sensory integration. Only when this integration of the sensory stimulus has taken place in the responsible brain centers can objects be recognized or writing read, for example. Only the sum of all sensory perceptions finally results in a perception or sensory system. One model of sensory perception is the so-called chain of perception. The starting point in the perception chain is the stimulus. This is generated by an object. The stimulus can be in the form of sound or electromagnetic waves, for example. This stimulus then hits the corresponding sensory cell, for example, the ear perceives sound. The cells in the corresponding sensory organ receive the stimulus, are excited by it and transform it. The converted stimulus is then transmitted to nerve cells. Often, preprocessing of the stimulus already takes place in the sensory organ itself. However, the main processing takes place in the sensory projection centers of the brain. Filtering, inhibition, convergence, divergence, integration and so-called top-down processes take place in these brain areas. Processing is followed by perception, which means that this is where the stimulus becomes conscious. For example, sound becomes sound or electromagnetic radiation becomes light. What is perceived is now remembered, combined, recognized, assigned or judged in the brain. These processes take place on the basis of previous experiences. Recognition is the basis for a reaction to the perceived stimulus. Whether acting is really still part of sensory perception is debatable. At the very least, action has an influence on the next run through the perceptual chain. After all, the reaction to the stimulus is stored as an experience and in turn influences the processing of subsequent stimuli. Visual perception is used by humans to perceive visual stimuli such as colors, lines, shapes, and motion. The eye is responsible for visual perception. Auditory or acoustic sensory perception takes place in the ear, or more precisely in the cochlea, the bony cochlea of the ear. Auditory sensory perception enables the perception of tones, sounds and noises. Another part of the ear is responsible for vestibular perception, or the sense of balance. Smells and fragrances are perceived via the olfactory sensory system. Here, particularly strong processing often occurs in the sensory centers, since many emotions are associated with odors. The gustatory sensory system is used for the reception of gustatory qualities. The associated sensory organ is the tongue with the taste buds.

Diseases and ailments

Sensory disorders can arise in the sensory organs themselves as well as in the processing brain centers or in the afferent neural pathways. We speak of sensory disorders when the processing of sensory impressions in the central nervous system is disturbed.Tactile, kinesthetic, visual, auditory and vestibular perception disorders are classified according to the individual senses. Auditory perception disorders are manifested, for example, by the fact that those affected have difficulty filtering out background noises or cannot distinguish between similar-sounding sounds or syllables. Visual perception disorders may be manifested by double vision, slow and stumbling reading, clumsiness, or simply eye burning and eye redness. In vestibular sensory disorders, the sense of balance is disturbed. Affected individuals have difficulty maintaining balance, sway when walking, and have difficulty orienting themselves in space. Children with a vestibular sensory disorder may stand out because they are extremely reluctant to swing. Only rarely do the perceptual disorders exclusively affect one area of the sensory system. Most often, a combined disorder is present. There are many causes of sensory dysfunction. The disorders can arise from congenital defects, as a result of developmental disorders, or due to deficits in hearing or vision. Of course, sensory function is also disturbed when there is impairment in the sensory organs themselves. In the eye, nearsightedness or farsightedness or diseases such as cataracts or retinal detachment impair sensory function. Diseases of the inner ear such as Meniére’s disease affect vestibular sensory function. Inflammation in the middle ear such as otitis media can affect hearing. Simple rhinitis, or a cold, is enough to negatively affect the olfactory process. A complete loss of olfactory sensory perception is called anosmia. A disturbance of olfactory perception also directly affects taste perception.