What the Researchers have to say about the Cerebellum

Many scientific researchers have published numerous articles linking an abnormality in the cerebellum with dyslexia, dyspraxia, ADD and ADHD.

The term "Cerebellar Developmental Delay" was proposed by Professor Roderick Nicholson of Sheffield University in 1990, whereby he and his co workers considered the idea that an abnormality of the cerebellum was linked to a number of the common learning and behavioural disorders.

Disorders of the Cerebellum: Ataxia, Dysmetria of Thought, and the Cerebellar Cognitive Affective Syndrome

By Jeremy D. Schmahmann, August 2004.

Many diseases involve the cerebellum and produce ataxia, which is characterized by in coordination of balance, gait, extremity and eye movements, and dysarthria. Cerebellar lesions do not always manifest with ataxic motor syndromes, however. The cerebellar cognitive affective syndrome (CCAS) includes impairments in executive, visual-spatial, and linguistic abilities, with affective disturbance ranging from emotional blunting and depression to dis-inhibition and psychotic features. The cognitive and psychiatric components of the CCAS, together with the ataxic motor disability of cerebellar disorders, are conceptualized within the dysmetria of thought hypothesis.

Rethinking the Lesser Brain

By James M. Bower and Lawrence M. Parsons, Scientific American, August 2003.

"Cognitive neuro-scientists using powerful new tools of brain imaging have found that the human cerebellum is active during a wide range of activities that are not directly related to movement. Sophisticated cognitive studies have also revealed that damage to specific areas of the cerebellum can cause unanticipated impairments in non motor processes, especially in how quickly and accurately people perceive sensory information."

Cerebellar Cognitive Affective Syndrome.

There has been persistent uncertainty as to whether lesions of the cerebellum are associated with clinically significant disturbances of behaviour and cognition. To address this question, 20 patients with diseases confined to the cerebellum were studied prospectively over a 7-year period and the nature and severity of the changes in neurological and mental function were evaluated.

The Cerebrocerebellar System

Investigations performed over the last decade however, have demonstrated for the first time the organization and strength of the connections that link the cerebellum with areas of the cerebral cortex known to be concerned with higher order behaviour rather than with motor control.

Attention-deficit/hyperactivity disorder: a preliminary diffusion tensor imaging study.

The purpose of this study was to explore whether there are white matter (WM) abnormalities in children with attention-deficit/hyperactivity disorder (ADHD).

Anatomical correlates of dyslexia: frontal and cerebellar findings.

The cerebellum is one of the most consistent locations for structural differences between dyslexic and control participants in imaging studies. This study may be the first to show that anomalies in a cerebellar-frontal circuit are associated with rapid automatic naming and the double-deficit subtype of dyslexia.

Cerebellar function in autism: functional magnetic resonance image activation
during a simple motor task.

Findings strongly suggest dysfunction of the autistic cerebellum that is a reflection of cerebellar anatomic abnormality. This neuro-functional deficit might be a key contributor to the development of certain diagnostic features of autism (e.g., impaired communication and social interaction, restricted interests, and stereotyped behaviours).

Cerebellum is involved in the pathophysiology of at least some cognitive deficits associated with ADHD

ADHD adults showed altered patterns of neural activity despite comparable performance on a verbal working memory task. These findings suggest that the cerebellum is involved in the pathophysiology of at least some cognitive deficits associated with ADHD and emphasize the need for additional research aimed at elucidating the role of the cerebellum in ADHD symptomatology.

Cognitive Impairments in Cerebellar Degeneration

To determine the specificity of cognitive impairments in patients with cerebellar degeneration (CD), the neuro-psychological test performance of 31 CD patients was compared to that of 21 patients with Huntington's disease (HD) and 29 normal adults.

Evidence for a cerebellar role in reduced exploration and stereotyped behaviour in autism.

Given consistent reports of cerebellar abnormality in autism, combined with animal research showing a relationship between exploration and the cerebellum, this study aimed to test the possible link between cerebellar abnormality and exploration in autism.

Hypoplasia of cerebellar vermal lobules VI and VII in autism.

Autism is a neurologic disorder that severely impairs social, language, and cognitive development. Whether autism involves mal-development of neuro-anatomical structures is not known. The size of the cerebellar vermis in patients with autism was measured on magnetic resonance scans and compared with its size in controls. The neocerebellar vermal lobules VI and VII were found to be significantly smaller in the patients.

Magnetic resonance imaging of boys with attention-deficit/hyperactivity disorder and their unaffected siblings.

The volumetric reductions in cortical gray and white matter in subjects with ADHD are also present in their unaffected siblings, suggesting that they are related to an increased familial risk for the disorder.

Quantitative brain magnetic resonance imaging in girls with ADHD

Anatomic studies of boys with attention-deficit/hyperactivity disorder (ADHD) have detected decreased volumes in total and frontal brain, basal ganglia, and cerebellar vermis.

Reduced cerebellar hemisphere size and its relationship to vermal
hypoplasia in autism.

Results indicated that the decreased size of the cerebellar hemispheres and vermal lobules VI through VII was associated with autism.

Global and regional gray matter reductions in ADHD: a voxel-based morphometric study.

The aim of this study is to examine cerebral gray (GM) and white (WM) matter abnormalities in a group of ADHD children using a voxel-based morphometry protocol.

Balancing and pointing tasks in dyslexic and control adults.

There were no significant differences between the dyslexic and control participants on the balancing tasks or when the speed and accuracy of pointing were analysed separately. However, when the speed and accuracy of pointing were combined, the dyslexic participants showed poorer performance than the controls (p = 0.045).

Association of abnormal cerebellar activation with motor learning difficulties in dyslexic adults

Developmental dyslexia, cerebellar/vestibular brain function and possible links to exercise-based interventions: a review

The Phonological Processing Deficit (PPD) hypothesis remains the most influential theory to explain why some children fail to acquire appropriate reading skills. However, current research suggests that there may be other deficits operating, and that the phonological processing deficit may be just one manifestation of a deeper underlying anatomical syndrome that originates in the cerebellar or vestibular areas of the brain. Claims that exercise regimes or programmes of vestibular stimulation may provide a 'cure' for developmental dyslexia (specific reading difficulties) prompt scepticism among the scientific community and raise concerns about the exploitation of vulnerable parents. The paper provides a review of research into the causes of specific reading difficulties at the behavioural, cognitive and biological level of explanation, and considers whether or not there is any theoretical basis for the use of exercise-based intervention programmes.

Diagnosis of vestibular disorders in learning disabled

Children with vestibular (inner ear) disorders and related postural disturbances constitute a large segment of the population described as learning disabled.

Dyslexia is more than a phonological disability

This article reports an extended case series of studies comparing performance of three age groups of dyslexic and matched controlled children on primitive skills. The dyslexic children showed deficits in most of the skills, with fundamental deficits (worse performance than reading age controls) on phonological skills, naming speed, bead threading on some balance tasks. Furthermore, there was no evidence of sub types of dyslexia, with all dyslexic children showing deficits in at least two skill modalities. The results, which have considerable theoretical and applied significance, demonstrate that the difficulties of dyslexic children are not limited to phonological skills.

Roderick I Nicholson and Angela J Fawcett
Published in Dyslexia Journal Vol 1, 1995 by John Wiley & Sons

Reappraising the cerebellum: what does the hindbrain contribute to the forebrain?

Although the cerebellum has traditionally been regarded as a motor mechanism, recent behavioural evidence indicates that the human cerebellum is involved in a wider range of functions: in learning, in planning, in judging time, in some emotional and cognitive disorders such as autism, and in some normal mental activities such as the cognitive processing of words. This evidence suggests that the traditional view of cerebellar function now needs to be reassessed and enlarged to include non-motor as well as motor functions in the human brain. Whereas the cerebellar connections to frontal motor areas enable the cerebellum to improve motor skills, cerebellar connections to adjacent association areas of the prefrontal cortex can enable the cerebellum to improve mental skills, and cerebellar connections to Broca's area can enable the cerebellum to improve language skills.