Ahhh…That Exciting Cerebellum!!

As we learn more about the way the brain works and how that functioning relates to movement, we are learning more about the incredible influence of the cerebellum on so many of our daily functions.  Historically the cerebellum has been relegated to the functions of balance and timing of movements.  Today, however, we now know that the cerebellum not only controls these functions but also influences motor skills in the timing in oculomotor control, timing and prediction of the  motor aspects of speech; ataxia of gait, visuo-kinesthetic interactions of limb movements; and prediction and anticipation of motor action.

Even more exciting is the growing body of evidence which supports the role of the cerebellum in cognitive functions. One function that is particularly of interest for occupational and physical therapists working in the area of sensory integration, is the cerebellum’s role in encoding internal models of action which support and influence the development of mental representations in the cerebral cortex.  This is the vital role of sensory integration intervention…to create those internal models.  In addition, these models and cognitive mental representations appear to be vital for the child’s ability to generate ideas for actions and motor planning.

New information is also emerging which supports the role of the cerebellum in sensory acquisition.  Schmahmann postulates a theory he calls “Dysmetria of Thought” which states that the cerebellum is critical for the modulation of sensorimotor, cognitive, and limbic functions through the integration of internal representations with external stimuli and self-generated actions.  Wow!!  What a powerful thought.  In addition to these functions, the cerebellum is also now believed to influence traditionally cortical executive functions such as working memory, mental flexibility, perseveration on task, problem solving, expressive language, verbal fluency, emotional control, attention, and mental representations of visual spatial relationships.  All of which rely on our ability to represent, hold and access information.

Numerous resources are available to therapists on this topic.  I recommend the following for basic introductions.  These can be highly technical resources but are worth the read.  The articles are available as open access via Google Scholar.  Enjoy!!

* Kandel, E., Schwartz, J., Jessell, T., Siegelbaum, S., Hudspeth, A.J. (2012). Principles of Neural Science, Fifth Edition.

* Fatemi, S. H., Aldinger, K. A., Ashwood, P., Bauman, M. L., Blaha, C. D., Blatt, G. J., … & Welsh, J. P. (2012). Consensus paper: pathological role of the cerebellum in autism. The Cerebellum, 11(3), 777-807.

* Manto, M., Bower, J. M., Conforto, A. B., Delgado-García, J. M., da Guarda, S. N. F., Gerwig, M., … & Timmann, D. (2012). Consensus paper: roles of the cerebellum in motor control—the diversity of ideas on cerebellar involvement in movement. The Cerebellum, 11(2), 457-487.

* Koziol, L. F., Budding, D., Andreasen, N., D’Arrigo, S., Bulgheroni, S., Imamizu, H., … & Yamazaki, T. (2013). Consensus Paper: The Cerebellum’s Role in Movement and Cognition. The Cerebellum, 1-27.

* Ito, Masao (2011-08-01). The Cerebellum: Brain for an Implicit Self (FT Press Science).

What’s the relationship between DCD and dyspraxia?

Many are understandably unsure of the relationship between Developmental Coordination Disorder (DCD) and dyspraxia. Though I’ll try to clear the issue here, I admit, it’s complicated.

First, the definition of “dyspraxia” is not always very clear and its current usage is not exactly synonymous with conceptualizations of praxis in general. I actually try to avoid the term dyspraxia altogether these days because it is not a terribly useful term due to its lack of clear definition. I prefer the term “praxis deficits,” which is more accurate. Praxis deficits may include problems with ideation or motor organization issues of motor planning, bilateral coordination, sequencing, or projected action sequences – all of which are aspects of praxis. Dyspraxia tends to refer only to motor planning problems and depending on the profession, can be even more restrictively defined as only problems with imitation of gestures. This is far more restrictive than our current understanding of praxis in general which can include problems with tactile-based motor planning, vestibular/prop-based bilateral coordination and sequencing problems, and ideational deficits.

The term was originally developed to try to standardize identification of motor performance problems (including praxis issues) in children so there was some uniform terminology and assessment for researchers. DCD was eventually included in the DSM as diagnosis. As a diagnosis, DCD is used very broadly and is usually perceived as an umbrella term that encompasses praxis deficits. The problem with the research and the hard core DCD people is that the gold standard assessment of DCD is the Movement ABC which, from a sensory standpoint, only taps into vestibular issues and does not address tactile-based motor planning. So, the majority of children identified in the DCD literature, if they only use the M-ABC, will be those with bilateral coordination and sequencing problems and not those with tactile-based motor planning. The hard core DCD people tend to make a distinction between “motor coordination” problems (which they usually identify as issues of balance, running, ball skills, etc. – what we identify as bilateral coordination and sequencing and projected action problems) and “motor planning” or “dyspraxia” problems (which they identify as problems of imitation of gestures).

So long answer to the question – the answer is not clear. DCD is generally perceived by OTs as a larger umbrella diagnosis with praxis deficits such as motor planning problems (dyspraxia) falling under the umbrella. However, your hardcore DCD people, including many in Canada and the UK, can be quite adamant that they are different issues. The DCD research literature will capture problems with praxis but they will largely focus on children with more vestibular/ bilateral coordination/ sequencing problems; though you have to read carefully as an OT will use the DCD term but may make a point of capturing kids with tactilebased issues as well.

There is amazingly little research specifically on praxis and even less recent research. Most current articles are in relation to imitation skills in children with autism. I think it is most important to realize DCD research will reflect mostly skill-based vestibular activity and, unless done by an OT, will not reflect specific problems in tactile-based motor planning.

For more stories, info, resources, facts and tips, go to www.thespiralfoundation.org



Helping Holly: Sensory Integration In A Captive Chimpanzee

In June 2009, I received one of the most unusual requests in my career as a sensory integration-based occupational therapist. The St. Louis Zoo had a chimpanzee named Holly, who was exhibiting behaviors different from other chimps: among other things she was neither grooming other chimps nor allowing herself to be groomed in a typical way. She plucked her hair excessively. She displayed body rocking movements and was seemingly fearless in situations where other chimps were more cautious. They hypothesized that Holly may have a chimp form of autism

Our colleague Dr. Margaret Bauman checked out Holly, and after careful review of the evidence she suggested instead that Holly had a form of sensory processing disorder (SPD). The Spiral Foundation was contacted, and I joined a team of experts bridging human and animal health disciplines to look into Holly’s condition.

I jumped at the chance to help, and started adapting some of our pediatric sensory integration checklists for use with chimps. Once the zoo staff administered the checklists to all of their chimps as a baseline, we administered additional tests to ensure that Holly’s differences were not simply personality traits.

With the combined data, I created a phased intervention program to address Holly’s particular needs. Phase one emphasized tactile and proprioceptive inputs to help her build body awareness and motor planning skills. The second phase was intended to strengthen her vestibular system and address deficiencies in her higher-level motor skills, with additional heavy work to solidify her proprioceptive gains from phase one. Happily, we found that after the treatments she demonstrated significant reduction of atypical and stereotypic behaviors, while increasing time spent in positive occupations such as resting and interacting with others.

From a researcher’s perspective, this unusual request holds interesting opportunities. In the short-term we have the opportunity to improve the life of an animal that was clearly out of sync with her environment. Longer term our work may help develop a chimp model of SPD, which could have far-reaching benefits for the welfare of chimps and other animals in captivity. Lastly, establishing a strong model and treatment for SPD in chimps and other non-human primates can help inform and advance diagnosis and treatment models in humans.

I have had a wonderful experience working with the St. Louis Zoo staff, the team working on Holly’s condition, and Holly herself. While I may never again get such an unusual request, this experience has opened my eyes to the universality of sensory experiences, regardless of age, gender, race, and now, species.

For more stories, info, resources, facts and tips, go to www.thespiralfoundation.org