Sensory Discrimination
Once the individual has registered and modulated sensory information coming in, he/she should be able to discriminate various aspects of the stimuli. Efficient sensory discrimination allows the individual to recognize the details both within the sensory input, and between different sensations (such as smell, taste, vision, and hearing). This is the “what is it” sense.
An individual can experience impairments in discriminating, or interpreting subtle qualities about, information from all of the sensory systems. The following examples may assist understanding the functional impact of deficits in discrimination of each sensory system:
External senses detect information from outside of the body (i.e. sounds, sights, touch, taste, and smells) and include:
Auditory Discrimination
Difficulty interpreting details of auditory information that is heard, including discernment of from where (direction and location) and from whom the sounds are coming
A skill which determines whether a person can attend, or become distracted, in a multisensory environment; and a skill that either enables or interferes with language development
i.e. the difference between “cat” and “cap”, who is talking, and where the sound is coming from
Visual Discrimination
Difficulty determining characteristics of sensory stimuli that are seen
i.e. ability to see the difference between “p” and “q”, recognize people’s faces, complete a puzzle, find a desired item/object among a complex background of other visual stimuli
Tactile Discrimination
Difficulty deciphering the qualities of sensory stimuli that are felt by touch, or on the skin
i.e. feeling the difference between rough/furry and smooth; feeling the difference between a quarter and a dime in your pocket; this also enables an individual to feel and locate where on the body that a stimuli was presented – i.e. elbow vs. forearm
Gustatory Discrimination
Difficulty discerning the characteristics of stimuli that are tasted (i.e. sour, sweet, spicy, etc.)
For children with these difficulties, feeding/mealtime routines are often impacted
Olfactory Discrimination
Difficulty interpreting the characteristics of stimuli that are smelled, as well as where the smell(s) is coming from
For children with these difficulties, mealtimes routines at home and school again may be impacted
Internal senses detect information from inside of the body (i.e. knowledge about gravity and movement) and include:
Vestibular Discrimination
Difficulty discriminating movement in space, and against gravity, with input from the inner ear. As the vestibular system provides information about the position and motion of our heads in relation to gravity, it also works simultaneously with the proprioceptive system to regulate muscle tone, develop postural control and balance, and provide a foundation for skill development in bilateral and eye-hand coordination
Deficits in discrimination therefore result in difficulty detecting the direction and/or speed of movement (whether falling to the side or backwards, and how fast the motion is), as well as the ability to efficiently use both sides of the body together and in isolation; all of which can hinder safety, catching one’s self upon tripping or falling, navigating various environments, ability to discriminate between right and left, and even development of hand preference
Proprioceptive Discrimination
Difficulty interpreting the characteristics of the stimuli sensed through the muscles and joint
Deficits therefore result in a distorted mental depiction of where the body is in space, joint instability, and grading of force; all of which allow us to discern how to pet a dog softly versus hammering a nail with force, how tightly to hold and utilize a writing utensil, walk into a familiar dark room without running into objects, and to climb stairs without having to consciously watch feet step up or down to subsequent steps