Lesser Known Disorders
Each issue of this series contains at least three lesser known disorders. Some of these disorders may contain subtypes which will also be presented. You will also notice that each disorder has a code. These codes represent the coding system for all disabilities and disorders listed in the Educator’s Diagnostic Manual(EDM) Wiley Publications.
Disorders in this issue:
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Tactile Defensiveness Sensory Integration Disorder (Immature Tactile Type)
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Proprioceptive Perceptual Sensory Integration Disorder
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Auditory Agnosia
LD 10.01-Tactile Defensiveness Sensory Integration Disorder (Immature Tactile Type)
Disability Category – LD
Definition
A type of sensory integration disorder specifically associated with difficulties in being touched because of an immature tactile system (Sensory processing disorder.com). Tactile defensiveness refers to a pattern of observable behavioral and emotional responses, which are aversive, negative and out of proportion, to certain types of tactile stimuli that most people would find to be non-painful (Chu, 2000).
Explanation
The tactile system is our sense of touch through different sensory receptors in our skin. We say that a child is “tactile defensive” when he or she is extremely sensitive to light touch.
One important role of our tactile system is its protective function that alerts us when something is unpleasant or dangerous. For some children, this function of the tactile system is not working normally. They may perceive most touch sensations to be uncomfortable or scary and react with a flight-or-flight response (Chu, 2000).
Theoretically, when the tactile system is immature and working improperly, abnormal neural signals are sent to the cortex in the brain which can interfere with other brain processes. This, in turn, causes the brain to be overly stimulated and may lead to excessive brain activity, which can neither be turned off nor organized. This type of over-stimulation in the brain can make it difficult for an individual to organize one’s behavior and concentrate and may lead to a negative emotional response to touch sensations Hatch-Rasmussen, 2001).
Often, children with tactile defensiveness will avoid touching the following (Sensory processing disorder.com):
- textured materials/items
- “messy” things
- vibrating toys, etc.
They may also be significantly bothered by, and avoid the following:
- a hug
- a kiss
- certain clothing textures
- seams on socks
- tags on shirts
- light touch or
- their hands being dirty
LD 10.02- Proprioceptive Perceptual Sensory Integration Disorder
Disability Category-LD
Definition
A type of sensory integration disorder specifically associated with difficulties knowing where one is in space. It is the sense of the position of our body parts in relation to our own bodies (Learning Disabilities Association, 2005; Hatch-Rasmussen, 2001)
Explanation
The proprioceptive sense is the sense of the position of our body parts in relation to our own bodies. This information is essential to coordinate and integrate movement because it allows us to know where we are in space. According to Hatch-Rasmussen (2001), the proprioceptive sense is responsible for providing the body with the necessary signals to allow us to sit properly in a chair or to step off a curb smoothly. Some common signs of proprioceptive dysfunction are:
- a lack of awareness of body position in space
- a tendency to fall
- clumsiness
- difficulty manipulating small objects
- eating in a sloppy manner
- minimal crawling when young
- odd body posturing
- resistance to new motor movement activities (Hatch-Rasmussen, 2001).
HI 1.01-Auditory Agnosia
Disability Category – Hearing Impairment
Definition
Auditory Agnosia refers to the inability to recognize specific sounds in the context of intact hearing. There is a distinction in this syndrome between pure word deafness, that is considered an agnosia for auditory/verbal information, and auditory agnosia, that involves an agnosia for environmental, nonverbal sounds. Cortical deafness is also a term applied to patients who essentially do not respond to any auditory information even when hearing is intact. Finally, receptive amusia is a term that refers to agnosia for music (National Academy of Neuropsychology, 2000).
Explanation
Agnosia is a rare disorder characterized by an inability to recognize and identify objects or persons despite having knowledge of the characteristics of the objects or persons. People with agnosia may have difficulty recognizing the geometric features of an object or face or may be able to perceive the geometric features but not know what the object is used for or whether a face is familiar or not.
Agnosia can be limited to one sensory modality such as vision or hearing. For example, a person may have difficulty in recognizing an object as a cup or identifying a sound as a cough. Agnosia can result from strokes, dementia, or other neurological disorders. It typically results from damage to specific brain areas in the occipital or parietal lobes of the brain. People with agnosia may retain their cognitive abilities in other areas (National Institute of Neurological Disorders and Stroke, 2005b).
HI 1.01a-Auditory/verbal information Agnosia
A type of auditory agnosia characterized by an inability to hear words.
HI 1.01b-Cortical deafness
A type of auditory agnosia characterized by an inability to respond to any auditory information even when hearing is intact.
HI 1.01c-Non verbal Auditory Agnosia
Non verbal Auditory Agnosia is the inability to hear environmental sounds such as a car starting or a dog barking.
HI 1.01d-Receptive Amusia
A type of auditory agnosia characterized by the inability to hear music.
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