First Report of a Canadian Epidemiological Study of Autistic Syndromes

Bryson, Susan E.; Clark, Barbara S.; Smith, Isabel M.

doi:10.1111/j.1469-7610.1988.tb00735.x

Cited by 266 publications

(114 citation statements)

References 24 publications

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“…The speech difficulties could be explained by severe hearing impairment, tracheostomy and cleft palate, and learning disability and autism also affected the ability to communicate. The rate of autism in the general population is about 1-2 in 1000 [Bryson et al, 1988;Gillberg et al, 1991;Gillberg and Wing, 1999;Wing and Potter, 2002]. Our data suggest that autism/atypical autism is much more common in CA than in the general population given that 40% of our comprehensively examined subjects met the criteria for autism/atypical autism.…”

Section: Prenatal Event Nmentioning

confidence: 72%

CHARGE association in Sweden: Malformations and functional deficits

Strömland

Sjögreen

Johansson

et al. 2005

American J of Med Genetics Pt A

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CHARGE association (CA) consists of a non‐random association of ocular coloboma (C), heart anomaly (H), atresia of choanae (A), retarded growth and/or development (R), genital hypoplasia (G), and ear anomalies and/or hearing impairment (E). A prospective multidisciplinary study of 31 Swedish patients with CA was undertaken in order to describe the associated malformations and functional deficits, find possible etiological factors and identify critical time periods for the maldevelopment. The clinical files were analyzed, the mothers answered a questionnaire on history of prenatal events, and a clinical evaluation of systemic findings, vision, hearing, balance, speech, oral and swallowing function, and neuro‐psychiatric function, especially autism, was performed. The most frequent physical abnormalities affected ears (90%), eyes (90%), brain (61%), heart (52%), retarded growth (48%), genitals (38%), choanae (35%), and facial nerve (32%). Sixty‐one percent of the patients were visually impaired or blind, and 74% had hearing loss or deafness. Problems in balance, speech, and eating were common. Forty percent of the patients had autism/atypical autism, and 82% had developmental delay. Three children were born following assisted fertilization and two mothers had diabetes. The mothers reported infections, bleedings, and drug use during pregnancy. Analysis of possible critical time periods suggested that most malformations were produced early in pregnancy, mainly during post conceptual weeks 4, 5, and 6. A multidisciplinary approach is essential in the assessment and management of CA. © 2005 Wiley‐Liss, Inc.

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Section: Prenatal Event Nmentioning

confidence: 72%

CHARGE association in Sweden: Malformations and functional deficits

Strömland

Sjögreen

Johansson

et al. 2005

American J of Med Genetics Pt A

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“…Rubenstein & Merzenich (2003) also stated that increased E:I ratio may be associated with some, but not all, forms of autism. The theory is based largely on the increased prevalence of epilepsy in ASC, which is estimated to occur in 5-46% of people with ASC (Bryson, Clark & Smith, 1988;Hughes and Melyn, 2005). None of the participants from whom data are reported here had epilepsy or any seizure history, therefore, on the basis of the current data, our suggestion for increased visuo-cortical inhibition is restricted to the Considering our present finding in the light of existing data, it is clear that there is a need for larger studies that use different approaches to measure neural inhibition including measuring sensory discrimination across modalities, measuring GABA levels across different areas of the cortex, and measuring peak gamma frequency in the same individuals.…”

Section: Differences (See Dickinson Et Al 2014 For a Full Discussion)mentioning

confidence: 99%

Superior orientation discrimination and increased peak gamma frequency in autism spectrum conditions.

Dickinson¹,

Bruyns‐Haylett²,

Smith³

et al. 2016

Journal of Abnormal Psychology

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While perception is recognised as being atypical in individuals with autism spectrum conditions (ASC), the underlying mechanisms for such atypicality are unclear. Here we test the hypothesis that individuals with ASC will show enhanced orientation discrimination compared to neurotypical observers. This prediction is based both on anecdotal report of superior discriminatory skills in ASC and also on evidence in the auditory domain that some individuals with ASC have superior pitch discrimination. In order to establish whether atypical perception might be mediated by an imbalance in the ratio of neural excitation and inhibition (E:I ratio) we also measured peak gamma frequency which provides an indication of neural inhibition levels. Using a rigorous thresholding method we found that orientation discrimination thresholds for obliquely oriented stimuli were significantly lower in participants with ASC. Using EEG to measure the visually induced gamma band response we also found that peak gamma frequency was higher in participants with ASC, relative to a well-matched control group. These novel results suggest that neural inhibition may be increased in the occipital cortex of individuals with ASC. Implications for existing theories of an imbalance in the E:I ratio of ASC are discussed.

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“…This compares with a ratio of 2-3:1 among schizophrenics presenting before 25 years quoted by Rosenthal (1970), and 2-1:1 for first admissions for schizophrenia between ages 20 and 24 years in England in 1984 (Government Statistical Office, 1986). Rutter & Tizard, 1970Bryson et al 1988Andrews & Harris, 1964Wing, 1981Broman et al 1987 disorders Male:female ratio 3-3:1 2-5:1 2-4:1 3-75:1 1-6:1 Goodman (1990) has reviewed the characteristics of neurodevelopmental disorders. In addition to boys being more vulnerable, he points out that such disorders (a) are over-represented among individuals with brain abnormalities; (b) show an association with pre-and peri-natal complications; and (c) have increased rates of left-handedness.…”

Section: Male Susceptibility To Neurodevelopmental Disordersmentioning

confidence: 99%