Since the first description of nonverbal learning disorder (NLD) was published in 1967, much research has been conducted elucidating its key features, its neuroanatomical associations, and the assessment procedures essential to establishing a diagnosis and treatment plan. Although there is theoretical and empirical evidence supporting the validity of NLD, awareness of this disorder is lacking, arguably in large part due to its absence in any formal classification system. This chapter reviews the scientific literature that has given rise to our current conceptualization of NLD. Clinical practice considerations are discussed as related to its assessment, diagnosis, treatment, and prognosis. These considerations are illustrated by a case study. The chapter continues with a discussion of issues in need of further research and the benefits of considering NLD in the context of the World Health Organization's classification system for describing health and health-related conditions. The chapter ends with a proposed definition of NLD.
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An “enigma.” That was the word used by her mother to describe Natalie. Prior to her first neuropsychological assessment, her parents had not been given a definite diagnosis or satisfactory guidance on how to best help her. During Natalie’s preschool and primary school years, she was given several diagnoses, including mild cerebral palsy, sensory integration dysfunction, and receptive language disorder. Another clinician advised that most times there is no answer. At 10 years of age, the gap between Natalie and her peers was noticeably widening, socially and academically. She still had difficulty finding her way around the small one-level school she had attended since kindergarten. At the time of her referral for a neuropsychological evaluation, the primary concerns revolved around her social functioning, her adaptive skills, her visual-spatial abilities, and her academic achievement.
Delays in Natalie’s development, however, were noted early on and resulted in her receiving several assessments and interventions that date back prior to the age of 2 years. Interventions prior to her neuropsychological assessment included occupational therapy, speech-language therapy, physical therapy, and special education. Psychoeducational assessments completed when she was 7 and 9 years of age indicated better verbal than nonverbal skills and abilities. Academic achievement testing at 9 years of age indicated average range scores on tests of word recognition, reading comprehension, written spelling, and listening comprehension, as well as a considerable weakness in her computation skills (less than the 1st percentile). Her first neuropsychological assessment at 10 years of age led to the diagnosis of nonverbal learning disorder (NLD).
Natalie’s history and assessment results, described below, are consistent with the features described often in the literature, especially in regard to children who present with the developmental or idiopathic form of NLD, which will be the focus of the present chapter. Natalie’s case illustrates several important points relevant to the assessment, diagnosis, and treatment of NLD. Prior to describing Natalie’s case in more detail, however, a selective review of the foundational knowledge leading to our current conceptualization of NLD is presented that will form the basis for understanding her clinical presentation. This is followed by a description of the sources of information needed to make a diagnosis of NLD, as well as a description of the typical early developmental history and the key clinical features of NLD as summarized from the literature. Following a presentation of Natalie’s case is a discussion of the current issues related to the conceptualization, assessment, diagnosis, and treatment of NLD. The chapter ends with a proposed description and definition of NLD.