The Prevalence of Thyroid Autoimmunity in Children with Developmental Dyslexia.

METHODS: We enrolled pediatric subjects with developmental dyslexia and, as a control group, healthy age- and sex-matched subjects without developmental dyslexia. Thyroid function was evaluated in subjects with developmental dyslexia measuring serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4). Thyroid autoimmunity was evaluated in all subjects measuring antithyroid peroxidase (TPO-Ab) and antithyroglobulin (TG-Ab) antibodies. In subjects with developmental dyslexia, thyroid ultrasonography (US) was also performed. RESULTS: We enrolled 51 subjects with developmental dyslexia (M : F = 39 : 12, mean age 12.4 ± 9 years) and 34 controls (M : F = 24 : 10, mean age 10.8 ± 4 years). TPO-Ab positivity was significantly higher in subjects with developmental dyslexia compared to controls (60.8% vs. 2.9%, p < 0.001), while no significant difference was found in TG-Ab positivity (16% vs. 5.8%). Thyroid US performed in 49 subjects with developmental dyslexia revealed a thyroiditis pattern in 60%. CONCLUSIONS: We found an extremely high prevalence of thyroid autoimmunity in children with developmental dyslexia. Further studies are needed to confirm our observations, but our findings may change the approach to this disorder and eventually lead to a systematic determination of thyroid autoimmunity in children with developmental dyslexia.

Near-infrared hemoencephalography for monitoring blood oxygenation in prefrontal cortical areas in diagnosis and therapy of developmental dyslexia.

The purpose of this study was to check empirically the relevance of the near-infrared hemoencephalography (NIR-HEG), which assesses local brain blood oxygenation, in facilitation of the diagnosis and behavioral therapy in dyslexics. The study was carried out in children and teenagers with physiologically recognized dyslexia, of three increasing age-groups: 6-7, 9-10, and 19-20 years old. Healthy age- and gender-matched subjects were used as controls. Left and right prefrontal cortical areas were targeted for the NIR-HEG measurements that were taken at baseline in both controls and dyslexics and then after a 10-day course of midriff breathing exercise combined with a standard vocal and writing training in dyslexics. The major finding was that in dyslexics, irrespective of age, the NIR-HEG indices were lower at baseline compared with those in healthy subjects. We further found that the indices improved after the respiratory and behavioral training in the youngest children, but not in the older age-groups. In conclusion, the study shows that deficient blood oxygenation in the prefrontal cortex is germane to shaping dyslexic symptoms in children. Cortical oxygenation improves in response to respiratory and behavioral therapy in a subset of young dyslexics. The NIR-HEG may facilitate the diagnosis of dyslexic disorder and the monitoring of behavioral therapy, particularly at early age.

Project DyAdd: Fatty acids in adult dyslexia, ADHD, and their comorbid combination.

In project DyAdd, we compared the fatty acid (FA) profiles of serum phospholipids in adults with attention deficit hyperactivity disorder (ADHD) (n=26), dyslexia (n=36), their comorbid combination (n=9), and healthy controls (n=36). FA proportions were analyzed in a 2x2 design with Bonferroni corrected post hoc comparisons. A questionnaire was used to assess dietary fat quality and use of supplements. Results showed that ADHD and dyslexia were not associated with total saturated FAs, monounsaturated FAs, or n-3 polyunsaturated FAs (PUFAs). However, those with ADHD had elevated proportions of total n-6 PUFAs (including gamma-linolenic and adrenic acids) as compared to those without ADHD. Dyslexia was related to a higher proportion of monounsaturated nervonic acid and a higher ratio of n-6/n-3 PUFAs. Among females none of the associations were significant. However in males, all the original associations observed in all subjects remained and ADHD was associated with elevated nervonic acid and n-6/n-3 PUFA ratio like dyslexia. Controlling for poorly diagnosed reading difficulties, education, dietary fat quality, or use of FA supplements did not generally remove the originally observed associations.

Project DyAdd: Fatty acids and cognition in adults with dyslexia, ADHD, or both.

Both attention deficit hyperactivity disorder (ADHD) and dyslexia are suggested to co-occur with altered fatty acid (FA) metabolism, but it is unknown how FAs are associated with the cognitive domains that characterize these disorders. In the project DyAdd, we investigated the associations between FAs in serum phospholipids and phonological processing, reading, spelling, arithmetic, executive functions, and attention. Healthy controls (n=36), adults with ADHD (n=26), dyslexia (n=36), or both (n=9) were included in the study. FAs included saturated, monounsaturated, total polyunsaturated, n-3, and n-6 FAs, together with n-6/n-3, AA/EPA, and LA/ALA ratios. When all the study subjects were included in the analyses, especially polyunsaturated FAs (PUFAs) were positively associated with cognition, but reading was least associated with FAs. These associations were modulated by gender, intelligence, n-3 PUFA intake, and group. Accordingly, within the ADHD group, only few associations emerged with PUFAs, n-6 PUFAs, and cognitive domains, whereas in the dyslexia group the more prevalent associations appeared with PUFAs and n-3 PUFAs.

Membrane fatty acids, reading and spelling in dyslexic and non-dyslexic adults.

Increasing evidence implicates functional deficiencies or imbalances of omega-3 and omega-6 fatty acids in dyslexia. The associations between literacy skills and omega-3 and omega-6 fatty acid status were examined. 32 dyslexics and 20 controls completed standardised tests of reading and spelling and gave venous blood samples for analysis of the polar lipid fatty acid composition of red blood cell (RBC) membranes. Relationships between literacy skills and omega-3 and omega-6 concentrations were examined using rank-order correlations. Better word reading was associated with higher total omega-3 concentrations in both dyslexic and control groups. In dyslexic subjects only, reading performance was negatively associated with the ratio of arachidonic acid/eicosapentaenoic acid (ARA/EPA) and with total omega-6 concentrations. There were no significant differences in membrane fatty acid levels between the dyslexic and control subjects. However, the finding that omega-3 status was directly related to reading performance irrespective of dyslexia supports a dimensional view of this condition, and our results also suggest that it is the omega-3/omega-6 balance that is particularly relevant to dyslexia.

Serum lipid fatty acids, phonological processing, and reading in children with oral clefts.

Reading skill is suggested to be related to phonological processing ability and polyunsaturated fatty acids (PUFAs). Here we investigated whether fatty acids (FAs) are related to phonological processing, whether the relations between PUFAs and reading generalize to other FAs, whether these relations are mediated by phonological processing, and whether relations of FAs are specific for language-related functions. Blood samples of 49 ten-year-old children with oral clefts were collected for FA proportion analysis in serum cholesteryl esters and phospholipids. On the same day, they performed tasks of phonological processing, reading, and both verbal and nonverbal intelligence. Sequential regression analyses (adjusted for age, gender, and cleft type) showed that phonological processing was inversely related to myristic acid in phospholipids and positively related to eicosapentaenoic acid in cholesteryl esters. Reading was inversely related to palmitoleic and gammalinolenic acids in phospholipids. The relations between FAs and reading were not mediated by phonological processing and FAs related only to language-related functions.

An explanation for the association between specific language impairment and toxemia.

An association between specific language impairment (SLI) and toxemia has been detected in several studies. No clear explanation for this association has been identified to date. However, a number of potential explanations have been offered. These include: (1) toxemia causes fetal anoxia which leads to brain damage; (2) toxemia in the mother is an indication of maternal immune attack on the developing brain; (3) the association between toxemia and SLI is indirect and arises because both are consequences of a common but as yet unknown etiological factor. In this paper we present a fourth possible explanation for the association. That is, that both SLI and toxemia may be the consequence of low circulating levels of essential fatty acids. Evidence supporting this hypothesis is presented and four possible mechanisms underlying the association are discussed.

Maternal antibody-mediated dyslexia? Evidence for a pathogenic serum factor in a mother of two dyslexic children shown by transfer to mice using behavioural studies and magnetic resonance spectroscopy.

The causes of dyslexia are unknown, but previous studies have suggested an immunological basis in some cases. We hypothesised that maternal antibodies, which cross the placenta and bind to fetal antigens, could be responsible, particularly when the dyslexia recurs in consecutive pregnancies. We injected serum samples from five mothers of two or more children with dyslexia into pregnant mice, and tested the offspring for behavioural abnormalities and cerebellar metabolites by magnetic resonance spectroscopy (MRS). Mice exposed in utero to serum factors from one woman with two dyslexic children, who had also had three spontaneous fetal losses, showed deficits in motor tests which correlated with cerebellar choline (Cho) and creatine (Cr) levels. These preliminary results are consistent with a role for maternal serum factors, probably antibodies, in causing some of the features of dyslexia, and possibly in other neurodevelopmental disorders.

Early dentine lead levels and educational outcomes at 18 years.

The associations between early dentine lead levels measured at the age of 6-8 years and educational outcomes measured at 18 years were examined in a birth cohort of 1265 New Zealand children. Analyses showed significant (p < .005) dose/response relationships between early dentine lead levels and later outcomes: at age 18 children with early elevated lead levels had poorer reading abilities, had more often left school early, had more often left school without qualifications, and had lower levels of success in school examinations. These associations persisted after statistical control for a range of social and familial confounding factors. A number of potential threats to the validity of the findings are examined, including sample selection bias, statistical undercontrol of covariates, and errors of measurement. It is concluded that the findings are consistent with the view that early mildly elevated lead levels have modest but detectable effects on individual achievement, with these effects extending to late adolescence.