More than tempting, it may allow us to have a false sense of security, as happens when we deal with executive functions (García-Molina, 2018; Tirapu-Ustárroz, Molina, Lago, & Ardila, 2012). But, as is already known, in these performances, many of the connected functions are acting together in a rather well-synchronized manner. This synchronization, and how we make our functioning automatic, is achieved through neurodevelopment.

In neurodevelopment, there are disorders or difficulties well-known to all who work in the field of child neuropsychology, where ADHD undoubtedly stands out, a disorder that still generates a bitter debate about its existence and/or real prevalence. But in general, and while bearing ASD in mind (another of the best-known disorders), it is quite frequent to find diagnoses that indicate problems in the development of the left hemisphere such as SLI, dyslexia or dysgraphia. However, when we move to the right hemisphere, it is more difficult to find information about disorders that are based on the incorrect functioning of this hemisphere.

However, Johnson and Myklebust (1967) had already described almost 50 years ago a cognitive profile in children who, far from presenting difficulties in those typical or language-related learnings, exhibited other types of problems, which were ultimately more difficult to objectify, in what they called non-verbal learning disability (NLD).

Given the considerable lack of knowledge we have about it, the aim of this post is to describe NLD, and to reflect on the reasons for it, which really seems to be behind the generally problematic diagnosis of neurodevelopmental disorders and the very reason why NLD is not recognized as such in the diagnostic guide that is commonly used, the DSM-V.

Non-verbal learning (NLD)

As I was saying, Johnson and Myklebust (1967) identified a sample of children who presented problems in the visuospatial domain, motor coordination difficulties and trouble understanding the social context, all of them closely related to difficulties with interpreting gestures associated with non-verbal language, which the authors linked to the functioning of the right hemisphere. Of course, these difficulties can affect more than the manipulative and perceptive aspects which can result in decreased performances in subjects that are not so “relevant” to school curriculum (physical or arts education), which in fact tells us of an asymmetry also at the academic level, where those right hemisphere abilities play less of a role than the left ones (García-Nonell, Rigau-Ratera, & Pallarés, 2006).

Features

Harnadek and Rourke (1994) described the identifying features of NLD syndrome:

• Bilateral tactile-perceptual deficits, usually more marked on the left side of the body.
• Bilateral psychomotor coordination deficiencies, often more marked on the left side of the body.
• Deficiencies in visual-spatial-organizational abilities.
• Difficulty in dealing with novel material and adapting to new and complex situations.
• Deficits in non-verbal problem solving, concept formation, and hypothesis testing.
• Distorted sense of time.
• Very strong rote verbal abilities.
• Verbosity that is rote and repetitive, with deficits in the pragmatic dimensions of language.
• Deficiencies in mechanical arithmetic.
• Significant deficits in social perception, social judgment, and social interaction skills.

In a way, it could be said that these children have a verbal ability frequently superior to age norms which suggests the left hemisphere compensates for the difficulties of the right hemisphere, just the opposite of what happens in children with language problems, who visually compensate their understanding of the environment.

At this point, we are going to focus on the three dimensions that are considered to be “primary” in NLD syndrome:

Motor coordination

One of the most easily observed deficits has to do with the acquisition of motor skills. In this regard, there may be a large overlap with the diagnosis of developmental coordination disorder (DCD) which is included in the DSM-IV.

Based on this idea, children with non-verbal learning disabilities could have difficulties in motor coordination, dyspraxia and, in general, would be labeled as “clumsy” by others, leading them to avoid games that involve motor skills.

This pattern is so prevalent that even other authors (Crespo-Eguílaz & García, 2009) consider it to be a focal point of one of the NLD labels proposed: procedural learning disorder (PLD).

In this sense, while language automatization is impaired in SLI—what is also labeled as learning difficulties in reading or writing—in NLD, the achievement of motor milestones would be significantly slower and, in addition, children with NLD would take much longer to learn motor patterns and they would also have a greater difficulty doing so.

Tests commonly used to identify motor coordination difficulties are the Movement Assessment Battery for Children (MACB–2), some subtests included in the Nepsy-II or the Cumanin subscales, although it is not a bad idea to note that there are more aspects to consider and not just the score obtained in these tests as such.

Visual-spatial perception

In the visual-spatial dimension, children with NLD may have difficulties with perceptual integration, specifically with visual organization of incomplete figures, as well as problems with sense of direction, estimation of size, shape, and distance.

These deficits are quite difficult to identify at first, mainly due to the subjectivity of the perceptive experience, but they give rise to a significant difficulty in the interpretation of visual material, which subsequently affects the memorization of this type of material.

In fact, the right hemisphere, which is predominantly visual, also plays an important role in the global interpretation of the environment. This obviously has an impact on the understanding not only of visual aspects but also on the integration of non-verbal communication, something we will discuss below.

Non-verbal language

Another major problem associated with NLD is the inability to comprehend non-verbal information, which is essential for effective communication, often changing the meaning of the verbal message. Children with NLD have trouble with aspects such as prosody and double meanings, but also interpreting non-verbal communication, which directly affects social interaction with their peers.

This last aspect is what also prompts other authors (Crespo-Eguílaz & García, 2009) to propose this PLD label and generate more organized criteria to define this disability. Simply considering a syndrome that includes prosodic aspects—as mentioned above—as a non-verbal language disability sounds a little contradictory.

Emotional impact

It is important to note that all these deficits have an important emotional impact on the child, mainly because of the labels “clumsy” or “weird” that result from the impact their difficulties have on the social domain. The lack of an official DSM diagnosis and adequate knowledge of this syndrome leads to an idea of intentionality regarding the child’s behavior (i.e., lazy for failing classes regarded as “easy”), with the child very aware of their limitations and constantly running into them when not receiving appropriate adaptations. This is in stark contrast with other disorders that have a more frontal lobe symptomatology, as children with NLD make more internal attributions to their performance).

A brief final remark

To the lack of knowledge about non-verbal learning disability we can certainly add a lack of knowledge about how to deal with neurodevelopmental disorders. Not surprisingly, it seems that the work carried out in this area is aimed at fitting the child into one of the pre-existing labels and detecting behaviors without addressing the reason behind them.

Specifically, many children with NLD have deficits in attention though they are derived from the difficulty to correctly process visual aspects—or at least to automatize their processing—without having an attentional problem per se. This brings us back to the beginning of the post. Observable behavior is the result of the interaction of many processes that have been synchronized during neurodevelopment and it is hard not to feel as though we are not delving into the problem if we do not pay attention to how this process has taken place, to the history of the children themselves and, in short, to what causes this way of carrying out tasks.

Perhaps that is why it is more difficult to describe NLDs and see them within diagnostic manuals that try to create labels as “hermetic” as possible. And, why not say it, directed to quick “diagnoses.”

It is therefore important to say that, even when there are a number of signs for NLD, each child exhibits a different profile, both regarding the existing signs, their presentation (which also varies with age) and the impact it has for each child and their family in their daily lives. This analysis certainly leads to a better understanding of how to provide the necessary support for a better adaptation to the surrounding world, which in the end is usually the goal we pursue: to help.

Bibliography

• Crespo-Eguílaz, N., & García, J. N. (2009). Trastorno de aprendizaje procedimental: características neuropsicológicas. Revista de neurología, 49(8), 409-416.
• García-Molina, A. (2018). Evaluación de las funciones ejecutivas.
• García-Nonell, C., Rigau-Ratera, E., & Pallarés, J. A. (2006). Perfil neurocognitivo del trastorno de aprendizaje no verbal. Revista de neurología, 43(5), 268-274.
• Harnadek, M. C., & Rourke, B. P. (1994). Principal identifying features of the syndrome of non-verbal learning disabilities in children. Journal of Learning Disabilities, 27(3), 144-154. https://doi.org/10.1177/002221949402700303
• Johnson, D. J., & Myklebust, H. R. (1967). Learning Disabilities; Educational Principles and Practices.
• Tirapu-Ustárroz, J., Molina, A. G., Lago, M. R., & Ardila, A. A. (2012). Neuropsicología de la corteza prefrontal y las funciones ejecutivas. Retrieved from https://dialnet.unirioja.es/servlet/libro?codigo=557535

If you liked this post about non-verbal learning disability written by the neuropsychologist Aarón F. Del Olmo, you might find his other articles interesting as well:

• Neuropsychological Assessment and Rehabilitation of Aphasia