How Are LD’s Diagnosed?

LD diagnosis is a messy field – lacking in standardization or agreement between experts. There are many protocols, driven by distinct definitions, practiced by assorted professionals.

  • EARLY RECOGNITION: It’s important to recognize many children with LD’s were first identified with “developmental delays” of one sort or another during infancy, toddlerhood, or the preschool years. While the chance of “outgrowing” a developmental delay (weakness) in this young age group (or having it respond favorably to direct “therapy”) is much greater than it is at school age or beyond, many developmental delays in young children evolve into LD’s later in life. Thus, it can be said that many LD’s are first diagnosed by specialists who work with very young children: Early Intervention Programs, Speech Pathologists, and Nursery School teachers.
  • IQ TESTING: The oldest, simplest, most widely accepted way of diagnosing an LD is with an IQ test. Two criteria are commonly used – one being a discrepancy of more than 15 points between the Verbal and Performance IQ scores, the second being a great deal of “scatter” or discrepancy between individual subtest scores within either the Verbal or Performance sections. While either of these findings suggests LD, they can be found at times in people who are functioning normally. Therefore, one must add the criteria of an actual delay in learning to these IQ observations in order to fashion a rational diagnostic method. This approach is the one most commonly used by school systems in states other than Massachusetts, under the federal PL 94-142 and the Individuals with Disabilities Education Act (IDEA).
  • ACHIEVEMENT TESTING: A third, quite straightforward, way of diagnosing LD, popular in Massachusetts public schools, dispenses with IQ/abilities testing altogether. Instead it focuses on reading, writing and arithmetic. In this scenario, a detailed battery of Individual Achievement Testing is carried out. Some (arbitrary) cut-off point is established for the amount of delay in a particular subject that is considered acceptable. If a child is delayed beyond the cut-off point, they are considered disabled and are given services. If their delays are not that severe, they are not considered disabled. This approach is appealing to some school systems because it’s cheap to administer & easy to understand. It seems outwardly “fair”. It skirts the question of “why” the delay exists, which could be seen as either an advantage or a disadvantage. This approach can be criticized as avoiding making the diagnosis of LD altogether, but rather simply giving help to those who are behind regardless of cause.
  • UP TO POTENTIAL?: A slightly more sophisticated version of the previous approach compares achievement test results not to the grade expectations or cutoff, but rather to the subjective impression of the child’s “potential” in the opinion of teachers & parents. Thus, a 2-year delay in math might be considered more problematic in a child who seems “bright” than in a child who seems “average”. Carrying that logic one step further, however, one wants to objectify the impression of potential using something like an IQ or some other abilities test, which brings to the next method.
  • MULTIDISCIPLINARY ASSESSMENT: Many medical centers (and some school systems) combine the above approaches. They use Individual Achievement Testing alongside Abilities Testing – either an IQ test or Neurodevelopmental Examination. The latter is more often used in medical settings for two reasons: First, it allows better “teasing apart” of the various developmental strengths & weaknesses than an IQ test, so that one can be more specific about what the LD is based upon. Second, a physician (Neurologist or Developmental Pediatrician) usually administers the Neurodevelopmental, bringing valuable medical perspective to the team. In any case, it is necessary to find weaknesses in abilities along with concomitant delays in achievement, and to be able to reasonably connect the two, in order to make a diagnosis of LD under this model. While the achievement-abilities combo should be seen as a “minimal” multidisciplinary team protocol, other tests & specialties can be and often are added – for instance, projective psychological assessment to look for emotional problems, OT or Speech evaluation, etc. All these things add to the depth of any evaluation, and thus lead to a richer and more complete understanding of the child.
  • “NEUROPSYCH” TESTING:A final way of diagnosing LD’s is the “neuropsychological” or “neuropsychiatric” evaluation. This is a very detailed battery that combines multiple tests administered from a neurological point of view, often by a psychologist under the supervision of a neurologist or, alternatively, by a psychologist with specific neurological training and background. The tests used combine abilities tests, achievement tests, and some neurological assessment. Such evaluations are often very helpful in painting a detailed picture of the child’s strengths and weaknesses and can be particularly useful when “normal” SPED techniques have been tried and failed to help a particular child. For initial diagnosis, however, a full neuropsychological evaluation can sometimes be “overkill” and yield more information than is practically useful.