Carolyn R. Garver

The pattern of sensory processing abnormalities in autism

The study was undertaken to evaluate the nature of sensory dysfunction in persons with autism. The cross-sectional study examined auditory, visual, oral, and touch sensory processing, as measured by the Sensory Profile, in 104 persons with a diagnosis of autism, 3–56 years of age, gender-and age-matched to community controls. Persons with autism had abnormal auditory, visual, touch, and oral sensory processing that was significantly different from controls. This finding was also apparent when the high and low thresholds of these modalities were examined separately. At later ages for the group with autism, lower levels of abnormal sensory processing were found, except for low threshold touch, which did not improve significantly. There was a significant interaction in low threshold auditory and low threshold visual, suggesting that the two groups change differently over time on these variables. These results suggest that sensory abnormalities in autism are global in nature (involving several modalities) but have the potential to improve with age.

Sensory correlations in autism

This study examined the relationship between auditory, visual, touch, and oral sensory dysfunction in autism and their relationship to multisensory dysfunction and severity of autism. The Sensory Profile was completed on 104 persons with a diagnosis of autism, 3 to 56 years of age. Analysis showed a significant correlation between the different processing modalities using total scores. Analysis also showed a significant correlation between processing modalities for both high and low thresholds, with the exception that auditory high threshold processing did not correlate with oral low threshold or touch low threshold processing. Examination of the different age groups suggests that sensory disturbance correlates with severity of autism in children, but not in adolescents and adults. Evidence from this study suggests that: all the main modalities and multisensory processing appear to be affected; sensory processing dysfunction in autism is global in nature; and sensory processing problems need to be considered part of the disorder.

Biomarkers of environmental toxicity and susceptibility in autism

Autism spectrum disorders (ASDs) may result from a combination of genetic/biochemical susceptibilities in the form of a reduced ability to excrete mercury and/or increased environmental exposure at key developmental times. Urinary porphyrins and transsulfuration metabolites in participants diagnosed with an ASD were examined. A prospective, blinded study was undertaken to evaluate a cohort of 28 participants with an ASD diagnosis for Childhood Autism Rating Scale (CARS) scores, urinary porphyrins, and transsulfuration metabolites. Testing was conducted using Vitamin Diagnostics, Inc. (CLIA-approved) and Laboratoire Philippe Auguste (ISO-approved). Participants with severe ASDs had significantly increased mercury intoxication-associated urinary porphyrins (pentacarboxyporphyrin, precoproporphyrin, and coproporphyrin) in comparison to participants with mild ASDs, whereas other urinary porphyrins were similar in both groups. Significantly decreased plasma levels of reduced glutathione (GSH), cysteine, and sulfate were observed among study participants relative to controls. In contrast, study participants had significantly increased plasma oxidized glutathione (GSSG) relative to controls. Mercury intoxication-associated urinary porphyrins were significantly correlated with increasing CARS scores and GSSG levels, whereas other urinary porphyrins did not show these relationships. The urinary porphyrin and CARS score correlations observed among study participants suggest that mercury intoxication is significantly associated with autistic symptoms. The transsulfuration abnormalities observed among study participants indicate that mercury intoxication was associated with increased oxidative stress and decreased detoxification capacity.

A clinical trial of glutathione supplementation in autism spectrum disorders

Summary Background Recent evidence shows that subjects diagnosed with an autism spectrum disorder (ASD) have significantly lower levels of glutathione than typically developing children. The purpose of this study was to examine the use of two commonly used glutathione supplements in subjects diagnosed with an ASD to determine their efficacy in increasing blood glutathione levels in subjects diagnosed with an ASD. Material/Methods The study was an eight-week, open-label trial using oral lipoceutical glutathione (n=13) or transdermal glutathione (n=13) in children, 3–13 years of age, with a diagnosis of an ASD. Subjects underwent pre- and post-treatment lab testing to evaluate plasma reduced glutathione, oxidized glutathione, cysteine, taurine, free and total sulfate, and whole-blood glutathione levels. Results The oral treatment group showed significant increases in plasma reduced glutathione, but not whole-blood glutathione levels following supplementation. Both the oral and transdermal treatment groups showed significant increases in plasma sulfate, cysteine, and taurine following supplementation. Conclusions The results suggest that oral and transdermal glutathione supplementation may have some benefit in improving some of the transsulfuration metabolites. Future studies among subjects diagnosed with an ASD should further explore the pharmacokinetics of glutathione supplementation and evaluate the potential effects of glutathione supplementation upon clinical symptoms.

A prospective study of transsulfuration biomarkers in autistic disorders (Neurochemical Research DOI: 10.1007/s11064-008-9782-x)

Plasma cysteine (lmol/l) 17.8 ± 8.3 (77 ± 5.8) 23.2 ± 4.2 (64) \0.001 5.3 (2) 36.8 (14) Plasma reduced glutathione (lmol/l) 3.14 ± 0.56 (75 ± 2.2) 4.2 ± 0.72 (120) \0.0001 0 (0) 26.3 (10) Plasma oxidized glutathione (lmol/l) 0.48 ± 0.16 (137 ± 7.4) 0.35 ± 0.05 (120) \0.001 60.5 (23) 13.2 (5) Plasma taurine (lmol/l) 48.6 ± 14.0 (50 ± 2.3) 97.5 ± 8.8 (27) \0.0001 0 (0) 100 (38) Plasma total sulfate (lmol/g P) 934 ± 252 (48 ± 2.1) 1,930 ± 184 (82) \0.0001 0 (0) 100 (38) Plasma free sulfate (lmol/g P) 1.37 ± 0.48 (33 ± 1.9) 4.1 ± 0.46 (67) \0.0001 0 (0) 100 (38)