A disorder that develops when nerve cells that perform a sensory function and conductors through which impulses are transmitted to the cerebral cortex are damaged. All sensitivity is divided into superficial and deep, while superficial sensitivity is divided into pain, temperature (cold and heat) and tactile. Disorders of the sensitive sphere are manifested by the following symptoms of irritation and prolapse:
1) pain, most pronounced when peripheral ditches, posterior roots, and optic nerve are involved in the process;
2) anesthesia is a complete loss of sensitivity or one of its types;
3) hypoesthesia – a decrease in the perception of all sensitivity or its individual types;
4) hyperesthesia – increased sensitivity to various types of stimuli;
5) hyperpathy – an extremely unpleasant painful sensation in response to even a slight irritation in combination with a prolonged aftereffect;
6) dysesthesia – a perverted perception of irritation, when touch is perceived as a prick, heat – as cold, etc.;
7) allocheiria – the irritating sensation appears not in the place of its application, but in the symmetrical half of the body;
8) polyesthesia – a single stimulus is perceived as multiple.