Excessive problems generating text is a sign of a written expression disorder, but it does not apply to spelling disorder. Refer to Table 38.1 for a list of signs indicating disorders in written expression or spelling.

Dyslexia is one of several distinct learning disabilities. It is a language-based disorder characterized by difficulties in single-word decoding, usually reflecting insufficient phonological processing. These difficulties are unexpected in relation to age and other cognitive and academic abilities. The difficulties are not the result of generalized developmental disability or of sensory impairment. Dyslexia is manifested by variable difficulty with different forms of language, often (not rarely) including problems with reading, writing, and spelling. This recently proposed definition reflects two important advances. First, instead of defining reading disorders generally, it focuses on one type of reading disorder. Second, it localizes the difficulty associated with dyslexia at the single-word level and pinpoints the cause as insufficient phonological processing. Although this definition has not gained universal acceptance, it represents a significant step forward in addressing some of the previous confusion and disagreement surrounding previous definitions of learning disabilities.

A diagnosis of disorder of written expression is not usually made before the child is at least 8 years old because normal difficulties in motor, spelling, and handwriting skills in younger children (e.g., letter reversals, invented spelling, inability to copy printed material) cannot be reliably differentiated from atypical problems. Mental retardation, impaired fine motor coordination, impaired vision or hearing, communication disorders, and attention-deficit/hyperactivity disorder (ADHD) are all associated with difficulties in various aspects of written expression. In a child with mental retardation, disorder of written expression may only be diagnosed if the child’s writing skills are significantly below those expected of children with that level of general intellectual functioning. Impaired vision and hearing can be ruled out through screening tests. Impaired motor coordination, arising from developmental coordination disorder or neurological damage, may produce illegible handwriting, but in the absence of additional impairments in spelling and expression of thought in writing, a disorder of written expression is ruled out. ADHD is frequently associated with difficulties in producing written work. A concurrent diagnosis is permissible, but caution is needed to determine whether the symptoms of ADHD have arisen de novo in the intermediate grades and are restricted to writing situations only, in which case a diagnosis of ADHD may be ruled out. Conversely, in the presence of a confirmed diagnosis of ADHD, caution is needed to determine whether the writing problems are reflected solely by careless spelling or punctuation errors and messy handwriting (as opposed to disordered handwriting), in which case a disorder of written expression may be ruled out. Language disorders frequently precede or may co-occur with a disorder of written expression.