Harold N. Levinson

THE CEREBELLAR-VESTIBULAR BASIS OF LEARNING DISABILITIES IN CHILDREN, ADOLESCENTS AND ADULTS: HYPOTHESIS AND STUDY ','

This paper provides a description of the cerebellar-vestibular-determined (CV) neurological and electronystagmographic (ENG) parameters characterizing 4,000 patients with learning disabilities. Of this sample, 1465 or 36.6% were children, 1156 or 28 9% adolescents, and 1379 or 34.5% adults. Using a set of diagnostic methods and criteria, the incidence of CV-dysfunction in this diverse sample was statistically equivalent to that reported by neurologists and neurotologists in a prior “blind” analysis of 115 dyslexic children. Over 94% of both the learning disabled and the dyslexic samples showed two or more abnormal neurological or ENG parameters indicating a CV-dysfunction whereas less than 1% evidenced hard neurological signs of a cerebral disorder. These and related data suggested that: (1) learning disabilities and dyslexia may be cerebellar-vestibular-based and reflect a single disorder and that (2) the varying academic, speech, concentration, activity, and related symptoms characterizing learning disabled persons seem to be shaped by a diverse group of cerebellar-vestibular-determining mechanisms rather than distinct neurophysiological disorders; also, (3) cerebellar-vestibular dysfunctioning and learning disabilities may secondarily trigger altered and/or compensatory cerebral processing and dominance mechanisms. (4) The cerebral cortex apparently plays a vital, compensatory role in shaping the final symptoms. A cerebellar-vestibular basis of learning disabilities is proposed. This conceptualization is consistent with, encompasses, and/or readily explains most of these clinical diagnostic, therapeutic, and research data as well as the many and varied hypotheses.

The Cerebellar-Vestibular Predisposition to Anxiety Disorders

To test for a cerebellar-vestibular (CV) predisposition to anxiety disorder, 402 consecutively referred subjects with varying anxiety symptoms were separated into eight DSM-III—R diagnostic categories and evaluated for CV dysfunction, using neurological and electronystagmographic (ENG) examinations. Of the total sample, 94% evidenced CV-dysfunction on the basis of two or more abnormal neurological or ENG parameters per subject. All DSM-III—R diagnostic anxiety-disorder categories contained a high percentage of abnormal neurological and ENG parameters, regardless of the size of the subsample. Moreover, each DSM-III—R subsample of anxiety disorders contained additional coexisting symptoms of anxiety sufficient to overlap with and form the basis for diagnosis of most other DSM-III—R anxiety-disorder categories. Such findings suggested that anxiety disorders, regardless of surface descriptions and DSM-III—R category, have a common denominator with varying symptom-shaping mechanisms and that this denominator is significantly CV-based. Although the above findings do not justify cause and effect convictions, they have provided crucial insights leading to (1) a proposed functional classification based on underlying determining mechanisms rather than on descriptions of symptoms, (2) a possible relationship between anxiety and learning disorders, and (3) a new method of treating these disorders by means of CV-stabilizing medications in conjunction with traditional approaches. Needless to say, independent and controlled studies, including comparisons with “normal” persons, are required for both validation and elucidation of those specific determining vs compensatory mechanisms and related diagnostic parameters crucial for symptom formation.

A Cerebellar-Vestibular Explanation for Fears/Phobias: Hypothesis and Study

To clarify and test the cerebellar-vestibular (CV) basis of fears/phobias, responses of 4000 learning disabled children, adolescents, and adults with neurological and electronystagmographic (ENG) evidence of CV-dysfunction were analyzed for anxiety-related symptoms. Of this sample, 64.6% indicated fears/phobias; females were significantly more predisposed; mixed-handedness was significantly related to fears of heights and reduced vestibular response or asymmetric vestibular functioning. Also, adults bad a higher incidence of the specific fears/phobias characterizing agoraphobia than children and adolescents. Analysis of factors reported as triggering the fears/phobias led to (1) a classification and theory of fears/phobias, obsessions/compulsions, and related anxiety symptoms based on realistic or traumatic, neurotic, and CV- or other CNS-based mechanisms rather than on DSM-III—R surface descriptions; (2) an understanding of the relationships between mitral valve prolapse, agoraphobia and panic episodes, as well as depression; and (3) new insights into differential diagnosis and selective treatment.

Dramatic Favorable Responses of Children with Learning Disabilities or Dyslexia and Attention Deficit Disorder to Antimotion Sickness Medications: Four Case Reports

Responses of four learning disabled children who showed dramatic improvements to one or more antimotion-sickness-antihistamines and -stimulants are described qualitatively. These cases were selected from a prior quantitative study in which three antihistamines (meclizine, cyclizine, dimenhydrinate) and three stimulants (pemoline, methylphenidate, dextroamphetamine) were tested in variable combinations (using a specific clinical method) for favorable responses by 100 children characterized by diagnostic evidence of learning disabilities and cerebellar-vestibular dysfunctioning. Pending validation in double-blind controlled studies, these qualitative results suggest that the “cerebellar-vestibular (CV) stabilizing” antimotion-sickness medications, Piracetam included, and their combinations may be shown to be therapeutically useful in treating children with learning disabilities or dyslexia and attention deficit disorder.

Abnormal Optokinetic and Perceptual Span Parameters in Cerebellar-Vestibular Dysfunction and Learning Disabilities or Dyslexia

To measure the ocular fixation and sequential scanning dysfunction assumed responsible for the visual reading symptoms which characterize dyslexia or learning disabilities, an optokinetically based tracking method was devised. This method quantitatively demonstrated significantly reduced fixation, tracking, and perceptual or visual-span scores as well as “movement illusions” for 70 cerebellar-vestibular dysfunctioning persons with learning disabilities vs 70 controls. Such data tended to validate the hypothesis that cerebellar-vestibular-determined fixation and tracking mechanisms predispose dyslexic or learning disabled individuals to visual reading disorders. Moreover, a newly revised method is presented which may prove useful in rapidly screening and diagnosing cerebellar-vestibular-determined reading and learning disorders from those of other origins. Additional independent studies using significantly larger samples and asymptomatic or “normal” controls are required for further validation and development of the method.

Abnormal Optokinetic and Perceptual Span Parameters in Cerebellar-Vestibular Dysfunction and Related Anxiety Disorders

As prior studies indicated abnormal cerebellar-vestibular-based sensorimotor mechanisms and neurological and ENG diagnostic parameters in anxiety disorders and because ocular fixation and sequential scanning are cerebellar-vestibular-modulated, it appeared reasonable to measure these and related ocular functions in matched samples of anxiety-disordered and control subjects. In this study, the optokinetically-determined fixation, sequential scanning, and perceptual span capacities obtained by means of a newly revised blurring-speed method were significantly lower or impaired in 70 anxiety-disordered patients vs 70 controls. Such data supported further the hypothesis that there may be cerebellar-vestibular predispositions to anxiety disorders and the optokinetically-based tracking method may prove useful in separating a diverse array of CV-determined or related anxiety symptoms from those of other origins. However, independent validation as well as additional studies of anxiety disorders using larger samples vs random or “normal” controls are required before conclusions are justified.

Neurophysiologic and Etiologic Correlations in Dyslexia: The Prospective Study

The unexpected discovery of a c-v “needle” in a massive clinical dyslexic “haystack,” and the surprising retrospective correlation of dyslexia with c-v dysfunction led to the design of a prospective study. The aim of this new study was to determine specifically the incidence and distribution of c-v and related neurophysiologic signs and symptoms in a reading-disabled “dyslexic” sample. With this aim in mind, 115 consecutively referred reading-disabled children were neuropsychologically examined, and the clinical data tabulated and analyzed. In addition, independent “blind” neurologic and “blind” caloric vestibular function (ENG) studies were performed on random subsamples, and the results similarly quantified and analyzed (Frank and Levinson, 1973).

A Summary in Cosmic Perspective

The spatial-temporal dimensions of dyslexia and its related cosmic-somatic-mental orbits and defensive “blind spots” have been explored and mapped via multiple qualitative and quantitative scientific “space probes.” Interestingly enough, this c-v disorder and its prior psychogenic and cortical etiologic conceptualizations were found to be dysmetric systems “with a distorted, non-Euclidian geometry in curved space, “where parallels intersect and straight lines form loops” (Koestler, 1968).

Anti-Motion Sickness Medications in Dyslexia

The experimental attempt to treat dyslexic individuals with anti-motion sickness medications was based on the following reasoning: (1) If, indeed, the sensory-motor dysmetria underlying dyslexia is of a primary c-v origin; and (2) if the cerebellum modulates the motion input in a manner analogous to its demonstrated role in modulating the visual, acoustic, proprioceptive and tactile input; and (3) if the anti-motion sickness medications improve the functional capacity of the cerebellum (and vestibular circuits) to process and modulate motion input and autonomic motion-sickness reflexes; then perhaps these very same “motion” medications may similarly improve the cerebellum’s capacity to modulate and harmonize the non-motion sensory-motor organismic dysmetria characterizing and underlying dyslexia. Furthermore, if these hypotheses are correct, any and all pharmacologically induced therapeutic responses in dyslexia may be viewed as neurophysiologic indicators suggesting that subclinically impaired c-v functional patterns were being compensated for by chemically improved c-v modulating and sensory-motor processing capacity. In addition, the chemically triggered and clinically observed conversion of “dyslexic” to improved or “normal” functioning may be utilized to highlight, and thus explore, the specific c-v neurodynamic role in dyslexic functioning, and to test the c-v potency of specific chemical agents.

The Cerebellar-Vestibular Role in Phobias and Related Mental Events

The discovery of the c-v role in phobias and related mental events was a natural and inevitable scientific outcome resulting from the correlation of data derived from three simultaneous paths of investigation: (1) the cross-sectional and longitudinal follow-up studies of dyslexic children into adulthood; (2) the retrospective and reconstructive analysis of adult dyslexic symptoms back to their childhood origin; and (3) the independent and simultaneous practice of psychiatry and psychoanalytic psychotherapy (Fig. 12–1).