A Quantitative Magnetic Resonance Imaging Analysis of the Cerebellar Deficit Hypothesis of Dyslexia

Recent work by Nicolson and Fawcett suggests the primary source of dysfunction in dyslexia is the cerebellum. In order to examine the cerebellar deficit hypothesis of dyslexia, 20 children with dyslexia (11 had co-morbid ADHD) and 20 without dyslexia (11 had ADHD, 9 were typically developing controls) were assessed with neuropsychological testing and quantitative MRI. Results demonstrated that volumes of both hemispheres and the vermis were not significantly different between groups (ps \u3e .10). However, children without dyslexia demonstrated greater rightward cerebellar hemisphere asymmetry compared to children with dyslexia, F(1,33) = 4.09, p \u3c .05. In addition, children with ADHD only were more comparable to controls in cerebellar asymmetry (none had reversed asymmetry); whereas those with co-morbid dyslexia and ADHD were more comparable to those with dyslexia. The relationship between cerebellar morphology and phonological processing also was assessed. For those without dyslexia, bilateral hemisphere volume moderately correlated with phonological awareness and phonological short-term memory (ps \u3c .05); hemisphere asymmetry moderately correlated with rapid naming errors (p.10), anterior vermis volume was moderately correlated with inattention, hyperactivity and impulsivity (ps \u3c .05) and right hemisphere volume was moderately correlated with inattention and hyperactivity (ps \u3c .05). Overall, our findings provide mixed support for the cerebellar deficit hypothesis of dyslexia. Although cerebellum morphology is atypical in some individuals with dyslexia, cerebellar morphology does not appear to be related to cognitive or motor dysfunction consistently. In our sample, cerebellum morphology may be related to about a third of our cases of dyslexia. Hence, dyslexia may be best accounted for by a combination of cortical and cerebellar contributions

The pars triangularis in dyslexia and ADHD: A comprehensive approach.

Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD. Participants included 50 children: 10 with dyslexia, 15 with comorbid dyslexia/ADHD, 15 with ADHD, and 10 controls. Using a 2 (dyslexia or not) x 2 (ADHD or not) MANCOVA, findings revealed PT length and shape were comparable between those with and without dyslexia. However, children with ADHD had smaller right PT lengths than those without ADHD, and right anterior ascending ramus length was related to attention problems in the total sample. In terms of linguistic functioning, presence of an extra sulcus in the left PT was related to poor expressive language ability. In those with adequate expressive language functioning, left PT length was related to phonological awareness, phonological short-term memory and rapid automatic naming (RAN). Right PT length was related to RAN and semantic processing. Further work on PT morphology in relation to ADHD and linguistic functioning is warranted

The relationship between cerebral hemisphere volume and receptive language functioning in dyslexia and attention-deficit hyperactivity disorder (ADHD).

Because poor comprehension has been associated with small cerebral volume and there is a high comorbidity between developmental dyslexia, attention-deficit hyperactivity disorder (ADHD), and specific language impairment, the goal of this study was to determine whether cerebral volume is reduced in dyslexia and attention-deficit hyperactivity disorder in general, as some suggest, or whether the reduction in volume corresponds to poor receptive language functioning, regardless of the diagnosis. Participants included 46 children with and without dyslexia and attention-deficit hyperactivity disorder, aged 8 to 12 years. Our results indicated that cerebral volume was comparable between those with and without dyslexia and attention-deficit hyperactivity disorder overall. However, when groups were further divided into those with and without receptive language difficulties, children with poor receptive language had smaller volumes bilaterally as hypothesized. Nonetheless, the relationship between cerebral volume and receptive language was not linear; rather, our results suggest that small volume is associated with poor receptive language only in those with the smallest volumes in both dyslexia and attention-deficit hyperactivity disorder

July 1964

Turf and Lawn Grass Association Better turf through research and Educatio

1964

Turf Management Club by John Traynor (page 1) Who Is Superintendent Here by H.E. Frenette (1) Good Turf Can Result from good Sodding (3) Golf Course Superintendent by Edwart Wiacek (4) Picture - Outstanding Senior Prof. Troll Picture - recognition for Blazers St. Andrew\u27s, Scotland by William Hynd (5) Analogy of a Turf Manager by James B. Cole (6) Fish Trouble by Peter A. Langelier and Dennis P. Leger (8) Square Rings by Robert P. McGuire (9) A Different Type of Course by Robert Hall (10) Literature by Pierre Coste (11) Weeds in Golf Course Turf and Their Control by John F. Cornman (A-1) The USe of Liquid Fertilizer by Anthony B. Longo (A-3) Fertilizing a Golf Course Through an Irrigation System by Herbert E. Berg (A-6) The Extent of Winter Injury on Golf Courses by James L. Holmes (A-11) The Problem of Winter Injury by James B. Beard (A-13) Establishing, Maintaining, and Selling Sod for Turf Areas in New England by George F. Stewart (A-20) Problems of Maintaining Turf Around Industrial Grounds by George Moore (A-22) Landscaping Industrial sites by A.W. Boicourt (A-25) Introduction to the panel Discussion on Grasses for Tees and Their Management by Alexander M. Radko (A-28) Building a Golf Tee by Phil Cassidy (A-29) Grasses for Tees and Their Management by Wm. Dest (A-31) Golf Course Tee maintenance by Jim Fulwider (A-32) Tees by F. Thompson (A-33) How to Draw up a Contract by Lawrence D. Rhoades (A-34) My Contract by Lucien E. Duval (A-37) The Golf Car Problem by Geoffrey S. Cornish (A-41) Golf Cars and Turfgrass by Lee Record (A-42) Course Design and Golf Cars by William F. Mitchell (A-42) Golf Cars and the Established Course by Sherwood Moore (A-45) Course Design and Golf Cars by Phil Wogan (a-52) Introduction of Cars to the New Course by M. Ovian (A-56

Performance of Normal and Dyslexic Readers on the Kaufman Assessment Battery for Children (K-ABC): A Discriminant Analysis

This study examined the utility of the Kaufman Assessment Battery for Children (K-ABC) in differentiating between normal and matched dyslexic readers. Significant differences between the groups were manifested on the cognitive subtests of Hand Movements, Number Recall, Word Order, and Matrix Analogies, in favor of the normal readers. The normal readers also produced significantly superior scores on each Achievement Subtest, the Sequential and Achievement Factors, and the Mental Processing Composite. One significant discriminant function was generated which accounted for 66 % of the variance between the groups of the K-ABC subtests. The discriminant analysis resulted in an overall 91 % correct classification rate. The exact nature of cognitive process-ing strategies employed by reading disabled children has long been the sub-ject of speculation. Some of the process-ing deficits postulated include sensory and perceptual dysfunction (Birch, 1962), poor efficiency of intersensory informa-tion transfer (Birch & Belmont, 1964, 1965), delayed development of lateral asymmetries (Orton, 1937), poor percep-tual-motor integration (Frostig, 1964