Wednesday, April 17, 2013

Disability seen with Reasoning: NVLD

Nonverbal Learning Disability (NVLD)
                Nonverbal Learning Disabilities affect many children, but can be difficult to diagnose early in a child’s life. These individuals usually have above average abilities when it comes to language. For example; they normally have very strong reading, writing, and vocabulary skills. The deficits occur in spatial processing and reasoning. Children with Nonverbal Learning Disabilities catch every detail when it comes to learning, but rather than being able to put all the details together, they miss the “big picture.” 

They also have problems socially. They do not pick up the nonverbal/social cues such as; gestures (body language), facial expressions, and tone of voice. These cues are primarily spatially based. Individuals with a Nonverbal Language Disorder may have difficulty in social situations because of their problems with spatial reasoning. These individuals also have trouble generalizing information they have, to new situations. Their ability to “carry – over” is impaired. All of the problems described above would be of major concern to a speech – language pathologist and how one would go about treatment. 

                There are three major areas that include specific symptoms associated with a Nonverbal Learning Disability (NVLD).

                The three areas are:

1.       Neuropsychological Deficits
a.       Includes difficulties with tactile and visual perception, psychomotor coordination, tactile and visual attention, nonverbal memory, reasoning, executive functions, and specific aspects of speech and language.

2.       Academic Deficits
a.       Includes math calculations, mathematical reasoning, reading comprehension, specific aspects of written language and handwriting (part of spatial reasoning).

3.       Social – Emotional Deficits
a.       Includes problems with social perception and social interaction.

For the purposes of this blog, we will focus on the Neuropsychological Deficits

·         Primary Neuropsychological Deficits:
o   Tactile perception
o   Visual Perception
o   Motor Coordination

·         Secondary Neuropsychological Deficits
o   Modality – specific aspects of attention
o   Extent to which children actively explore their environment.

·         Tertiary Neuropsychological Deficits
o   Abstract Reasoning
o   Spatial Reasoning
o   Executive Functions
o   Specific aspects of speech and language.
Prefrontal Cortex

Executive Functioning is one of the primary impairments in individuals with NVLD. Executive function describes the processes the brain uses to create, organize, and follow plans. These functions include higher level abilities, such as:
·         Abstract Reasoning
·         Logical Analysis
·         Hypothesis Testing
·         The ability to change from one thought to another mentally.

Executive functioning, reasoning, and abstract thinking are all cognitive functions of the prefrontal cortex, which is shown in the picture above. Even though this deficit in executive functioning, which includes abstract and spatial reasoning, may not be seen in all individuals with a Nonverbal Learning Disorder; it is thought that this deficit is a problem with subcortical white matter. The deficit in the subcortical white matter is responsible for the symptoms seen in NVLD. Whether it is directly related to right hemisphere systems (which was the first assumption) or the inability to access these right hemisphere systems due to deficits in white matter (which is the present assumption), it is believed to result in this disorder. These deficits are usually more common in cases of severe NVLD. (Rourke, 1995).
Some conditions that can lead to white matter areas of the brain being affected are:

·         Callosal Agenesis: congenital disorder where there is a partial or complete absence of the corpus callosum.

·         Hydrocephalus: too much fluid in the skill that can lead to brain damage.

·         Multiple Sclerosis: disease that attacks the Central Nervous System that destroys connects from
                                 the brain to the rest of the body.

·         Certain types of TBI: Traumatic brain injuries. 

The symptoms of a Nonverbal Learning Disorder may be similar to symptoms someone might see in other disorders. For example, individuals with:

·         Right Hemisphere Dysfunction:
o   This would be differentiated from NVLD by more severe speech prosody deficits, more pronounced deficits with planning and organization, and more severe tactile – spatial deficits.

·         Asperger’s Syndrome:
o   This would be differentiated from NVLD based on the degree of functioning an individual has.
o   For low functioning individuals, they may be more properly diagnosed with autism.
o   For high functioning individuals who have been diagnosed with Asperger’s syndrome, they may have been misdiagnosed and actually have a NVLD.

·         Central Processing Disorders

Even though the symptoms for the above disorders may overlap with Nonverbal Learning Disabilities, they can be differentiated by proper assessments. Some of the tests that may be administered to assess problems of executive functioning are:
·         The Wisconsin Card Sorting Test
·         The Trail Making Test
·         The Progressive Figures and Color Form Test
·         Assessments that also test working memory and attention might also be used to assess this problem.

·         There is no cure to reduce symptoms of NVLD. It is important for the intervention to focus on helping individuals compensate for the deficits that they do have. This depends on proper diagnosis. If an individual is experiencing any of these deficits they need to have a neuropsychological evaluation to figure out their strengths and weaknesses with this disorder. 



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