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Friday, October 4, 2013

A recent study by Jean Hebert and colleagues published in Science (9/5/13) provided important experimental evidence that a genetically induced inner-ear impairment in mice was linked to hyperactivity and thus might cause ADHD in humans.(

However, a brief discussion of the vital but frequently overlooked role of the inner-ear and its supercomputer, the cerebellum, as well as related clinically based data are deemed crucial to furthering a holistic understanding and theory of ADHD.

The role of the inner-ear or vestibular system underlying cognitive and behavioral disorders and their treatment were contributed to by many gifted clinicians and therapists, including Ayers, DeQuiros and Blythe. However, the role of both the inner-ear and cerebellum in determining ADHD dates back to the pioneering dyslexia research of Frank and Levinson initially published in 1973, and then evolving over four decades. By recognizing that dyslexia and ADHD are significantly overlapping disorders characterized by imbalance and dyscoordination, Levinson proposed that both disorders stem from one common impairment-- a signal-scrambling dysfunction of inner-ear/cerebellar origin. His ADHD data and concepts were published in numerous papers and summarized in his book Total Concentration. Significantly, these concepts are consistent with the cerebellar research of Noble Laureate Sir John Eccles and outstanding others as well as inner-ear clinicians called neurotologists, hence gaining their support.

To explain this signal dysfunction, Levinson utilized a simple analogy: "Just imagine the symptoms induced by spinning until dizzy. When dizzy you can't properly read, write, speak, recall, think, plan, concentrate, orient, balance and coordinate. It's as if the signals transmitted to varied brain structures are 'dizzy' or scrambled and so cannot be normally processed. They thus induce temporary dyslexic or ADHD-like states. Its the dizzy or scrambled signals that are considered etiologically most important, not necessarily the conscious sensation or experience of dizziness which may lessen, disappear or be absent."This analogy also explains how and why signal stabilizing medications, including inner-ear enhancing antihistamines and stimulants, are so effective in treating both dyslexia and ADHD. And it further explains the efficacy of anti-vertigo therapies in preventing the inner-ear triggered reading reversals ("space dyslexia") and impaired concentration, orientation and balance ("space ADHD") in orbiting astronauts.

Although many researchers believe that ADHD is due to a primary impairment within the thinking brain-- the frontal cerebral cortex, this theory cannot explain the results of worldwide neuroimaging studies indicating that the cerebellum is significantly involved. Nor is this primary brain damage theory of ADHD capable of encompassing or explaining a wide range of other clinical realities such as the favorable prognosis of most with ADHD, its overlapping with other disorders having similar inner-ear determined imbalance and dyscoordination signs and symptoms, its favorable therapeutic response to inner-ear enhancing therapies, its causation by diverse inner-ear and cerebellar impairments, etc. Nor is this ADHD theory compatible with the inner-ear results of the genetic study just published in Science by Herbert et al..

By contrast, Levinson's concept of ADHD readily encompasses and/or explains all other theories and related data, including the genetic inner-ear/hyperactivity study previously mentioned. According to Levinson:

ADHD results when initially normal frontal lobe and related brain structures secondarily fail to process the scrambled signals received. These "dizzy" signals are due to a primary dysfunction within the inner-ear and cerebellum. And depending upon predisposing variables, these distorted signals may trigger compensatory neuroplastic brain changes and/or possibly impair the brain structures receiving them.

Clearly, the value of any theory lies entirely in its ability to encompass, explain and predict all pertinent data. To-date, Levinson's inner-ear/cerebellar theory of ADHD significantly satisfies these criteria. Importantly, the new inner-inner-ear data presented within Science definitively supports Levinson's concepts of ADHD vs those suggesting a primary cerebral origin.