A third core feature is that the learning difficulties are readily apparent in the early school years in most individuals (Criterion C). However, in others, the learning difficulties may not manifest fully until later school years, by which time learning demands have in- creased and exceed the individual’s limited capacities.
Another key diagnostic feature is that the learning difficulties are considered ”spe- cific,” for four reasons. First, they are not attributable to intellectual disabilities (intellec- hearing or vision disorders, or neurological or motor disorders) (Criterion D). Specific els of intellectual functioning (generally estimated by an IQ score of greater than about 70 [:5 points allowing for measurement error]). The phrase ”unexpected academic under- achievement” is often cited as the defining characteristic of specific learning disorder in that the specific learning disabilities are not part of a more general learning difficulty as manifested in intellectual disability or global developmental delay. Specific learning dis- order may also occur in individuals identified as intellectually "gifted." These individuals may be able to sustain apparently adequate academic functioning by using compensatory strategies, extraordinarily high effort, or support, until the learning demands or assess- ment procedures (e.g., timed tests) pose barriers to their demonstrating their learning or accomplishing required tasks. Second, the learning difficulty cannot be attributed to more general external factors, such as economic or environmental disadvantage, chronic absen- teeism, or lack of education as typically provided in the individual’s community context.
Third, the learning difficulty cannot be attributed to a neurological (e.g., pediatric stroke) or motor disorders or to vision or hearing disorders, which are often associated with prob- lems learning academic skills but are distinguishable by presence of neurological signs.
Finally, the learning difficulty may be restricted to one academic skill or domain (e.g., read- ing single words, retrieving or calculating number facts).
Comprehensive assessment is required. Specific learning disorder can only be diagnosed after formal education starts but can be diagnosed at any point afterward in children, adoles- cents, or adults, providing there is evidence of onset during the years of formal schooling (i.e., the developmental period). No single data source is sufficient for a diagnosis of specific leam- ing disorder. Rather, specific learning disorder is a clinical diagnosis based on a synthesis of the individual’s medical, developmental, educational, and family history; the history of the learning difficulty, including its previous and current manifestation; the impact of the diffi- culty on academic, occupational, or social functioning; previous or current school reports; portfolios of work requiring academic skills; curriculum-based assessments; and previous or current scores from individual standardized tests of academic achievement. If an intellectual, sensory, neurological, or motor disorder is suspected, then the clinical assessment for specific learning disorder should also include methods appropriate for these disorders. Thus, compre- hensive assessment will involve professionals with expertise in specific learning disorder and psychological/cognitive assessment. Since specific learning disorder typically persists into adulthood, reassessment is rarely necessary, unless indicated by marked changes in the leam- ing difficulties (amelioration or worsening) or requested for specific purposes.