Page 1 of 9 Next Page

NLD and Asperger's Disorder

Joe Palombo

Nonverbal Learning Disabilities, Chapter 11, pages 205-218

Controversy exists as to the relationship between NLD and Asperger's disorder. Some believe that at a minimum, children with Asperger's disorder have NLD but that few children with NLD have Asperger's disorder. An additional confound to diagnostic clarity is introduced by the concept of autistic spectrum disorder (ASDs). This disorder, along with diagnoses of pervasive developmental disorder (PDD) and PDD-NOS (not otherwise specified), blur the distinction between individuals with autism and those with higher-functioning autism, Asperger's Disorder, or NLD. Furthermore, in a critical review of the construct of Asperger's disorder Klin and Volkmar (2003) found that, in their research, investigators' have either modified the DSM-IV (American Psychiatric Association, 1994) criteria by treating Asperger's disorder and high functioning autism interchangeably or used altogether different criteria for their definition of the condition. They conclude the Anosologic status of AS [Asperger~ disorder] is, therefore, extremely problematic, given that studies cannot be necessarily compared because of the adoption of different diagnostic definitions, and there has been no comparison across different diagnostic schemes with regard to the relative usefulness of each of the schemes (p. 8). Finally, confusion exists because the term Asperger's disorder rather that Asperger disorder is used in many publications (e.g., Klin, 1994; 2004; Volkmar &: Klin, 1998,2000), the terms appear to be interchangeable. In this work, I use the term Asperger's disorder in conformity with the DSM-IV designation (American Psychiatric Association, 1994) except when I refer to investigators who use the term Asperger's syndrome instead.

If differentiations are to be drawn between NLD and Asperger's disorder, they must be made at the level of the three perspectives that we have discussed: the neurobehavioral, the social, and the intrapersonal. Although we may find an overlap among the neuropsychological deficits of both conditions, major demarcations exist between the social features and the intrapersonal dynamics of each.

We face several obstacles in our effort to differentiate NLD from Asperger's disorder. The first problem relates to the fact that different disciplines use different criteria in making a diagnosis. NLD is a diagnosis made by neuropsychologists but not by psychiatrists. On the other hand, both psychiatrists and neuropsychologists make the diagnosis of Asperger's disorder, which is included in DSM-IV (American Psychiatric Association, 1994). Neuropsychologists and psychiatrists use different theoretical frameworks to arrive at their decisions. Each discipline considers different aspects of children's functioning to be diagnostically significant. Psychiatrists and psychotherapists are often unfamiliar with the diagnosis of NLD. Similarly, neuropsychologists often take little notice of motivational or psychodynamic issues in their assessment of a child's difficulties. Consequently, comparing diagnoses made by different disciplines is fraught with difficulties.

A second problem is fueled by the absence of agreement among researchers as to the core deficits that define each disorder. The issue centers on whether the neuropsychological deficits or the social impairments define the disorder. This viewpoint has led to the suggestion that we create a distinct label, such as SELD (social-emotional learning disability), to distinguish the problems of those children from children who have specific neurocognitive impairments. Current research on the neurobiology of{social cognition may provide answers to these diagnostic problems. Borrowing from social and cognitive psychology, neuropsychologists and neurologists rely on constructs such as social cognition to identify domains of psychological function. The issue remains unresolved.

A third problem is that the use of a dimensional approach encourages the blurring of boundaries in an effort to underscore the fact that the children present with heterogeneous symptoms that vary in number, type, age of onset, and severity: The limits of this approach are reached when the disSimilarity between specific phenotypes raises questions as to whether two disorders belong within the same continuum. The choices as to which set of features is necessary for inclusion within the disorder, the level of severity of the symptoms, the level of cognitive impairment, and the age at which the diagnosis is made-all contribute to the inaccuracy of the diagnostic process.

The final obstacle is that of overcoming the limits of the perspective that each discipline brings to the diagnostic process. In this work I have advocated the use of multiple perspectives that are integrated to provide a developmental viewpoint that specifies the way in which each child's mental processes organize and integrate his or her experiences into a coherent whole.

The question we confront is whether NLD is a disorder that is distinct from Asperger's disorder, with its own social features, or whether it belongs within the autistic spectrum along with Asperger's disorder? I argue that NLD is distinct from Asperger's disorder and does not belong in the autistic spectrum. A further question relates to the construct of SELD, which encompasses many of the developmental deficits currently included under the diagnosis of PDD, and would include NLD. It does not appear wise to dismiss that construct at this time because researchers have not pursued it sufficiently. Eventually, it may have some value in making important differentiations.