(An earlier version of this article appeared in the New Zealand TS Support Group’s March ’99 newsletter.)

I heard that Learning Disability (LD) was a possible complication for people with TS when I first learned about Turner’s. However, I didn’t hear the term ‘Nonverbal Learning Disability syndrome’ (NLD) until some time later. NLD is the type of learning difference that can be a part of Turner’s Syndrome. I’d heard the phrase, ‘visual spatial processing difficulties’ and I’d heard that because of these difficulties, a few people with Turner’s don’t drive, and that many will have trouble learning math. But over the last year I’ve learned more about NLD. As a teacher, a parent and a student, I bring my particular bias to this learning: that is, that each learner is different, regardless of which label best fits with the testing. I believe people with LD can perform at a level equal with others, if the education adjusts for individual differences.

Luckily, my first source of information on NLD happened to be a book edited by Byron Rourke. In that book, (Rourke, 1995) notes that NLD consists of, ‘tactile-perceptual, psycho-motor, and visual-perceptual deficits . . . ’. In general terms, these deficits impact most on ability to manage novel situations, on complex motor tasks, and on conceptual math, and social skills. They leave simple motor, auditory perception, rote memorization, verbal and reading skills largely unaffected. In chapter 13, on Turner’s Syndrome, Joanne Rovet notes that ‘ . . . 55% of these subjects have a learning disability, compared with 26% of controls . . .’ and that, ‘ . . . there is considerable variability among adults with TS, including excellent adjustment and adaptation . . . ’. Later, Rourke looks at the degree to which the learning style of the different disorders discussed in the book fit into the NLD model. Rourke then places Turner’s Syndrome at level 2, in which ‘A considerable majority’, (but not ‘virtually all’), ‘ . . . of the NLD assets and deficits are evident.’

Perhaps the most important thing I’ve learned about NLD is that it is an invisible disability. We believe in what we can see. When we see a child is very short, we can deduce that this will create a barrier to hanging up her coat on a high hook, because we see the difference in height. We see a need to use a help like a step stool, or to have a separate hook entirely. But when we look at a staircase and perceive that one end is high and the other low, we presume, if the next person is not blind, that they see the same. If we find that a young child is afraid of heights, we may wonder if he is phobic. But we are unlikely to guess that he does not distinguish how high the steps are, and so can’t tell how to use them safely. If a clearly bright child, sitting at the top of a long flight of steps, announces proudly that she is going to do a somersault, we will make the most obvious guess, that this is a reckless child, perhaps even hyperactive. It is not clear to us that an otherwise precocious preschooler might take no meaning from their visual environment. If the child was dull-witted that might be our first guess, but it does not occur to us with a youngster of average or even superior intelligence.

This past November, the Turners Society in the US hosted Dr. Allan Reiss at the XI Annual Conference. Professor Reiss, Director of the Division of Child & Adolescent Psychiatry and Child Development at Stanford University School of Medicine, appeared as a keynote speaker, giving a talk entitled Ability, Brain Development & Function in TS. In his talk Reiss emphasized that even when there are learning disabilities, children and adults with T.S. nearly always have normal total IQ scores. He stressed that deficits, when present, will be relative weakness, with Verbal intelligence (VIQ) greater than performance intelligence (PIQ). Reiss discussed his 1995 study of 30 girls with TS and a control group of 30 age-matched girls. That study revealed differences, with the girls with TS having a smaller proportion of brain tissue (grey and white matter) in both the right and left parietal regions, an area involved in performing visuo-spatial tasks. Reiss also discussed his 1993 twin study, of otherwise identical sisters, only one of whom has TS. Reiss’s study showed structural differences in neuroanatomy with a decrease in grey matter in some areas in the sister with Turner’s, and a corresponding 25% increase in cerebrospinal fluid (CSF). Both girls had total IQ scores showing intelligence in the superior range, but the twin with TS differed from her non-Turner sister in her performance score, which was lower than her (typically developing) twin by 18 points. The twin with TS had a verbal score higher than her performance IQ by 15 points. Sue Thomson, an educator who writes about practical interventions and advocacy in NLD, states that a split (of even) 10 points in favor of verbal IQ should be a red flag alerting us to a possible need for intervention.

While Dr. Reiss noted that these cognitive deficits represent relative weakness only, he nonetheless observes that many aspects of success in daily living are related to brain function. He stressed that, "we must optimize genetic potential with the appropriate environment" and that to do so we must define the paths of influence and understand them. In discussing his research, Reiss observed that when you understand the biological basis of LD, that can lead to an improved understanding of the interaction of age, environment, and other potentially contributing factors. While Dr. Reiss was speaking in general terms, this appears to hold equally true on an individual basis. More than any overall diagnosis, individual differences matter if we wish to assist individuals. If we presume a child’s difficulty signifies a behavioral issue, when in fact behavioral problems are secondary to primary difficulties with sensory processing, we can create as many problems as we solve. NLD is an invisible disability, but like the child with a physical difference, the child with NLD may need to learn things in a separate way entirely. It is up to us to see that our children get the help that is right for them.