Tactile discrimination
One of the most well known and most researched is two-point discrimination, the ability to differentiate between two different tactile stimuli which are relatively close together.
[3] Tactile discrimination is something that can be stronger or weaker in different people and two major conditions, chronic pain and blindness, can affect it greatly.
Blindness increases tactile discrimination abilities which is extremely helpful for tasks like reading braille.
[5] One other major application of tactile discrimination is in new prosthetics and robotics which attempt to mimic the abilities of the human hand.
This section of the brain tracks what the muscles are doing at all times so any potential damage to this area can greatly affect one's senses.
[7] There are many types of receptors in the somatosensory pathway including: Stereognosis (Tactile Gnosis) is defined as the ability to tell the difference and identify objects via touch in the absence of visual or auditory contact.
The subject will need to be able to recognize temperature, spatial properties, texture, and size to reach an accurate conclusion to what the object is.
The purpose of this form of tactile discrimination is to detect any defects in the Central nervous system such as lesions in the Brainstem, Spinal cord, Thalamus, or Sensory cortex.
In order for this test to be carried out successfully, it is imperative that the subject's primary sensations be fully functional.
It is also important that the practitioner and the patient communicate ahead of time about the orientation of the characters, as well as where on the body the figures are to be drawn (usually on the palms of the hand).
[16] Two-point discrimination (2PD) is a neurological examination in which two sharp points are applied to the surface of a part of the body in order to see if the patient recognizes them as two discrete sensations.
[17] By conducting this form of tactile discrimination, it is believed that practitioners will be able to discern the relative amount of nerves in the tested location.
Research studies have shown that the 2PD test does a poor job of determining the degree to which the nerves regain their function after damage, as well as determining the sensory failures in the first place, owing to this form of tactile discrimination's simplicity, crudeness, and dependence on anecdotal evidence.
Braille allows the blind to be able to use their sense of touch to feel the roughness, and distance of various patterns to be used as a form of language.
Essentially, the occipital cortex allows one to effectively make judgements on the distance of braille patterns, which is related to spatial discrimination.
[4] Meanwhile, the somatosensory cortex allows one to effectively make judgements on the roughness of braille patterns, which is related to two-point discrimination.
[21] Some non-neuropathic chronic pain conditions have been shown to decrease tactile acuity, the ability to precisely detect touch.
[5] As robots and prosthetic limbs become more complex the need for sensors capable of detecting touch with high tactile acuity becomes more and more necessary.
[6] These sensors can be placed meaningfully throughout the surface of a prosthetic or a robot to give it the ability to sense touch in similar, if not better, ways than the human counterpart.
