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Questions and Answers
Questions and Answers
Question # 17
Is NLD is being "over-diagnosed"?
There are some indications that NLD is being "over-diagnosed." The reason for this probably involves a multitude of factors, not all of which can be discussed here. What we can focus on are some of the attributes that lead to misdiagnosis or, as I would prefer to call it, "misclassification." Perhaps the following examples of some recent events in our clinic/laboratory will help to clarify some of the relevant issues.
Over the past few months, we have seen three youngsters who carried a diagnosis of NLD. They were so classified by apparently well-meaning practitioners. However, none of the three met our criteria for definite or probable NLD.
The common presenting characteristic of these three youngsters (11 years, 13 years, and 15 years of age) was a Verbal IQ > Performance IQ discrepancy of some 15 to 20 points. Furthermore, all had academic achievement scores in arithmetic calculation well below their scores on single-word reading.
On these bases, the diagnosis of NLD was formulated and conveyed. Of course, the parents wanted to know more about NLD. After investigating various sources of information, they determined that their children were probably misdiagnosed, but they wanted to have a comprehensive neuropsychological examination to confirm this impression.
The three youngsters in question had remarkably similar profiles. All exhibited the following:
(1) No evidence of any significant problems in somatosensory (tactile/haptic) skills.
(2) Normal to superior levels of performance on almost all measures of visual-perceptual-organizational skills.
(3) No evidence of problems in speeded eye-hand coordination. All exhibited well developed, even advanced, athletic skills, especially in basketball. (All reported being able to dribble a basketball behind their back and between their legs.)
(4) Much interest in new experiences, especially those of a challenging nature.
(5) Normal to superior levels of performance on tests of complex problem-solving, concept-formation, and hypothesis-testing. All exhibited formal operational thought at levels commensurate with their ages.
(6) Well-developed capacities for sustained attention to visual and auditory stimuli.
(7) No difficulty on tests for visual and auditory memory.
(8) Adequate development of the linguistic dimensions of form, content, and function.
(9) Involvement in the study of mathematics at an advanced-for-age level.
(10) Made appropriate eye-contact with the examiner throughout the day-long examination.
(11) Reported having many friendships that had been developed and sustained over several years.
It should be clear that these characteristics (with the exception of auditory attention and memory and well-developed linguistic form) are quite atypical in youngsters of these ages who exhibit NLD. Indeed, virtually none of them is ever encountered in older children with NLD.
In all three cases, the parents were somewhat dumbfounded by the diagnosis of NLD. When they looked into the principal characteristics of NLD and the rules of classification, they arrived at the conclusion that either they or the professionals who made the original diagnosis were sadly mistaken.
This was especially disconcerting to the parents because many, if not most, of the elements of the treatment program that we have generated for youngsters with NLD were highly recommended to them. For example, social skill groups and experiences, assistance within the classroom with visual-spatial material, and eye-hand coordination exercises were recommended in two of the three cases.
These three sets of parents (and, possibly, their children) experienced quite needless anxiety and foreboding about the future. All of the parents were very eager to confirm the diagnosis or to receive an explanation about why it had been applied in the first instance. All of them were also concerned that their children might exhibit a comorbid diagnosis of Attention Deficit Disorder. Of course, none did. It was clear that the lack of attention that these youngsters paid to many dimensions of scholastic activity could be explained easily in terms of their boredom with, and lack of interest in, rather pedestrian and mundane pursuits.
One important conclusion to be taken from this discussion relates to the use of a limited number of criteria for the formulation of classification decisions. For example, when a diagnosis of NLD is based primarily on a VIQ>PIQ discrepancy, there is a high probability of misdiagnosis. See Question #11, where we report that in our studies of 9- to 15-year-old children, a significant VIQ>PIQ discrepancy was evident for only 27% of those who were classified as definite or probable NLD.
Summary and Conclusions. It is somewhat gratifying to see that practitioners are becoming more sensitive to NLD. That said, it is quite regrettable that a more complete (i.e., adequate) picture of NLD appears to have eluded some of them. This is an unfortunate example of "a little knowledge turning out to be a bad thing." In this particular instance, the problem extends well beyond a purely intellectual exercise. Indeed, it is one that can have--and, in the cases cited, did have--a severe negative impact on these families.
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