Although NLD is often being promoted as a rather new term within the broader area of 'learning disabilities', in reality the notion of a nonverbal learning disability has been considered since the earliest days of LD diagnosis. In essence, a nonverbal learning disability describes a situation in which the underlying cause of a student's learning difficulties is believed to be a generalized weakness in the ability to cognitively process nonverbal information. Typically, such a student performs quite well verbally (both receptively or 'listening' and expressively or 'speaking') but struggles to understand or remember information which is presented visually. This is not due to poor vision but is related to an assumed weakness in the brain's ability to fully or efficiently process nonverbal information.
In the early days of LD diagnosis and treatment, evaluators would frequently look at differences between Verbal and Nonverbal (Performance) IQ scores in order to diagnose learning disabilities. A relatively low Performance (or nonverbal) IQ score suggested underlying visual or perceptual processing difficulties which were believed to be the cause of the student's learning difficulties. As our professional understanding of cognitive processing broadened, it became apparent that there was much more to most learning disabilities than simply a difference between verbal and nonverbal abilities. Ultimately, it was found that many students who were formerly believed to have visual or perceptual processing weakness were more accurately diagnosed through other processing models. As a result, the visual/auditory or verbal/nonverbal comparison lost favor as a diagnostic process.
So why has the NLD term made such a dramatic comeback in recent years? Well, as with many other educational theories which lose favor and then are later resurrected, it seems that psychologists and other educational diagnosticians have found reason to believe that certain subgroups of LD students not only demonstrate the old 'verbal vs. nonverbal' discrepancy but also frequently demonstrate other social and behavioral characteristics which set them apart from other LD students. These characteristics frequently include difficulty accurately perceiving social situations, confusion with nonverbal communication, and generalized social disinterest or avoidance.
Because of the rather unique cluster of behaviors and cognitive skills found with these NLD students, some professionals have even suggested the need for a separate NLD special education category. Other educational professionals are skeptical of the need or appropriateness of such a classification and note that this same pattern of behavioral and cognitive skills is found in many students who have been identified within the category of Autism Spectrum Disorder (ASD) and more specifically, Asperger's Disorder (formerly known as 'high functioning autism'). In fact, it has been suggested by some that many of the students who are currently being given the NLD diagnosis may more appropriately be identified within the ASD special education category.
In any case, the primary factor in diagnosing a true nonverbal learning disability is the documentation of a generalized weakness in nonverbal or visually-based information processing skills. This continues to be most accurately evaluated though formal cognitive assessment by an instrument (or battery of instruments) which evaluates both verbal and nonverbal abilities and provides broad cluster scores in both of these areas. Students with nonverbal processing weakness will typically struggle most with academic tasks which involve complex or abstract visual displays (charts, graphs, maps, etc.) and which provide limited verbal or auditory information. These students will generally have most difficulty in the areas of math and spelling (due to poor visualization) but may also struggle with hands-on activities (science labs, etc.). Reading and creative writing skills will probably be relatively strong.
When students are found to demonstrate both nonverbal learning difficulties and also rather significant and unusual social/behavioral characteristics, the possibility of an underlying Autism Spectrum Disorder should not be overlooked.
Although CAPD has recently been promoted as a rather new term within the broader area of 'learning disabilities', in reality the notion of an auditory or language-based learning disability has been considered since the earliest days of LD diagnosis. In essence, a Central Auditory Processing Disorder describes a situation in which the underlying cause of a student's learning difficulties is believed to be a generalized weakness in the ability to cognitively process verbal or 'auditory' information. Typically, such a student performs quite well nonverbally (with visual or 'hands-on' activities) but struggles to understand or remember information which is presented verbally. This is not due to poor hearing but is related to an assumed weakness in the brain's ability to fully or efficiently process auditory information.
In the early days of LD diagnosis and treatment, evaluators would frequently look at differences between Verbal and Nonverbal (Performance) IQ scores in order to diagnose learning disabilities. A relatively low Verbal IQ score suggested underlying auditory or language-based processing difficulties which were believed to be the cause of the student's learning difficulties. As our professional understanding of cognitive processing broadened, it became apparent that there was much more to most learning disabilities than simply a difference between verbal and nonverbal abilities. Ultimately, it was found that many students who were formerly believed to have verbal or auditory processing weakness were more accurately diagnosed through other processing models. As a result, the visual/auditory or verbal/nonverbal comparison lost favor as a diagnostic process.
So why has the CAPD term made such a dramatic comeback in recent years? Well, as with many other educational theories which lose favor and then are later resurrected, it seems that psychologists and other educational diagnosticians have found reason to believe that certain subgroups of LD students not only demonstrate the old 'verbal vs. nonverbal' discrepancy but also often demonstrate other characteristics which set them apart from typical LD students. These characteristics frequently include difficulty maintaining attention, difficulty with detailed memorization, and generalized difficulty with planning or organizational skills.
Because of the rather unique cluster of behaviors and cognitive skills found with these CAPD students, some professionals have even suggested the need for a separate CAPD special education category. Other educational professionals are skeptical of the need for such a classification and note that this same pattern of behavioral and cognitive skills is found in many students who have been identified with generalized sequential processing difficulty or some form of attention deficit disorder (ADD or ADHD).
Clearly, the primary factor in diagnosing a true auditory processing learning disability (such as CAPD) is the documentation of a generalized weakness in verbal or language-based information processing skills. This continues to be most accurately evaluated though formal cognitive assessment by an instrument (or battery of instruments) which evaluates both verbal and nonverbal abilities and provides broad cluster scores in both of these areas. If problems are also being identified in nonverbal areas (such as the Coding subtest of a Wechsler IQ test) the CAPD diagnosis may not be appropriate. Students with real auditory processing weakness will typically struggle most with academic tasks which involve lectures or written instruction and which provide limited visual or nonverbal information. These students will generally have most difficulty in the areas of reading and writing due to difficulty processing or expressing language-based information. Math will probably be relatively strong.
When the CAPD diagnosis is being considered it is very important not to overlook the possibility of generalized sequential processing weakness and/or an underlying attention deficit disorder.
The term 'Severe Discrepancy' refers to one of the primary components of most State and/or local guidelines for determining if a student is eligible for special education services related to a specific learning disability. Although the real basis of a learning disability is an assumed information processing weakness, 'severe discrepancy' between ability and achievement is the standard method used to determine how much impact the processing problem has on a student's actual achievement. 'Discrepancy' is a measure of underachievement (the difference between ability and achievement) and 'severe' refers to how much underachievement is required by a given State or district before a student will qualify for special education services. Each State establishes its own criteria for determining a severe discrepancy.
In the 'old days' a standard 'rule of thumb' for establishing significant underachievement (and even for identifying a learning disability) was the determination of 'two years below grade level' in any of the basic academic skill areas (reading, math, or writing). Unfortunately, using that criteria, very few students below the 4th grade and over 25% of those above the 8th grade would qualify for service simply based upon that level of discrepancy. Over time much more sophisticated and statistically sound methods have been established to provide a more 'fair and accurate' measure of severe discrepancy across grades and ages of individual students.
Currently, the process of establishing a severe discrepancy typically involves the administration of individualized ability (IQ) and academic (achievement) tests and a direct comparison of obtained standard scores (generally based upon a student's age rather than grade placement). Standard scores typically are on a scale with a mean (or average score) of 100 and an average range extending roughly from 90 to 110. The obtained IQ and achievement scores are then compared in order to determine if a severe discrepancy exists.
Some States use a simple discrepancy criteria which establishes a standard score difference (for example, 20 points) between overall IQ score (usually the Full Scale IQ) and specific areas of achievement. Other States use a much more complex 'regression formula' to determine how significant a discrepancy is between ability and achievement. A regression formula is generally considered more accurate because it takes into consideration the correlation between ability and achievement tests and also the phenomenon of 'regression toward the mean' in which it is been found that students tend to achieve at a level a bit closer to the mean (100) than their IQ score would otherwise predict. In other words, a student with an IQ score of 85 is expected to have an achievement score somewhat higher than 85. The main thing to remember about a regression formula is that the number of points required for a 'severe discrepancy' is different depending upon how far the obtained IQ score is from the 'mean' of the test (100). For virtually all States or districts, the possible areas of severe discrepancy established by Federal guidelines include:
Another thing to note about discrepancy calculations is that most States highly recommend (if not require) that a 'global' or 'Full Scale' IQ score be used when comparing a student's intellectual ability and achievement.
The term 'Special Education' or 'Special Ed' refers to specialized instruction, modifications, and accommodations which are 'necessary' in order for a student to receive a 'free and appropriate public education'.
Return to the LDinfo Web Site to find out about any of the following topics (and more):
Learning disabilities - what is a learning disability (LD or SLD)?
Dyslexia: Dyslexia is a reading disability or reading disorder
Dysgraphia Dysgraphia is a writing disability or disorder
Dyscalculia Dyscalculia is a math disability or disorder
What is an attention deficit disorder (ADD, AD/HD, ADHD)?
Gifted LD: Can a student be gifted and LD?
Emotional/Behavioral issues and LD: Do LD students experience behavior problems or depression?
Section 504: What is a Section 504 plan?
What is special education?
What is processing?
What is a severe discrepancy?
What is a nonverbal learning disability (nonverbal LD or NLD)?
What is a central auditory processing disorder (CAPD)?