Nonverbal learning disability – is it possible to define it in terms of CHC theory? Part two.

  

Is it possible to define NVLD in terms of CHC?

(I recommend reading part one, the previous post, before reading this one).

In order to define NVLD in terms of CHC, we'll look at the steps of learning disability definition according to Flanagan's model, using CHC theory.  Since I haven't found literature dealing directly with this subject, I'll try to use the information presented in the previous post.

Step 1: Significantly low achievement in reading/ reading comprehension/writing/written expression/mathematics.  It's probable that NVLD children will have significantly poor achievement in math and maybe also in reading comprehension and written expression.  But as stated in the previous post, this criterion is not always met in NVLD children.  When it's not met, the child is not learning disabled.  Mammarella &  Cornoldi  write, that contrary to other learning disabled children, the academic weaknesses of children with NVLD may be moderate and not dramatic.  So it's possible, according to these authors, that the label NVLD is not correct (at least in these cases).  The authors suggest the name "specific nonverbal disorder" or "specific visuospatial disorder".  In case the child meets the first step, it's possible to move on to the next step:

Step 2: One (or more) cognitive ability is significantly below average.  NVLD children may have poor Visuospatial Processing , Processing Speed, and maybe lowered Fluid ability.   They also may have poor Working Memory.  As for Long Term Storage and Retrieval, NVLD children may poor Free Recall (of visual stimuli, for instance in the RCFT).  Probably not all these abilities will be lowered simultaneously in each NVLD child.  In the 2012 CHC model (see the first presentation in the series "Intelligence and Cognitive Abilities" in the right hand column of this blog), there are more cognitive abilities that are likely to be lowered in NVLD children: Psychomotor Speed, Psychomotor Ability, Tactile Ability and Kinesthetic Ability.

Step 3:  There is a logical or an empirical connection between the poor academic achievement and the low cognitive abilities.  This criterion may be met in an NVLD child having mathematics difficulties that can be explained by poor Visuospatial Ability.   Reading comprehension difficulties can be related to poor Fluid Ability (in the aspect of integration of parts into a whole and understanding implicit meaning in texts).

 

Step 4: Most cognitive abilities are intact.    NVLD children are likely to have intact Comprehension Knowledge and Auditory Processing, as well as intact  Memory Span.  As for Long Term Storage and Retrieval,  most narrow abilities are likely to be intact (Free Recall of auditory stimuli, Naming Facility, Ideational and Word fluency, Meaningful Memory).  It's possible that Fluid Ability will also be intact, especially if assessed with nonvisual tests.  When the lowered abilities are Visuospatial Processing and  Processing Speed and the other cognitive abilities are intact, this criterion is met.   

Step 5: Exclusionary factors (insufficient instruction, immigration, emotional difficulties etc.) are not the main reasons for the poor academic achievement.  It's possible that NVLD children will have emotional and social difficulties that are secondary to the cognitive disabilities and are not a main reason for the poor academic performance.

To summarize, there certainly will be children with symptoms of NVLD that we can diagnose as learning disabled using this definition, within CHC theory.  Other children, presenting most symptoms but without significantly poor achievement in reading, writing and/or math, will not be diagnosed as learning disabled, not according to the CHC definition, nor according to any other learning disability definition.