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Alexandra J Richardson

Publications and source records attributed to Alexandra J Richardson.

12 recordsLinked to original sources
PubMed2006

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.

Adult↗
PubMed2006

Omega-3 fatty acids in ADHD and related neurodevelopmental disorders.

Omega-3 fatty acids are dietary essentials, and are critical to brain development and function. Increasing evidence suggests that a relative lack of omega-3 may contribute to many psychiatric and neurodevelopmental disorders. This review focuses on the possible role of omega-3 in attention-deficit/hyperactivity disorder (ADHD) and related childhood developmental disorders, evaluating the existing evidence from both research and clinical perspectives. Theory and experimental evidence support a role for omega-3 in ADHD, dyslexia, developmental coordination disorder (DCD) and autism. Results from controlled treatment trials are mixed, but the few studies in this area have involved different populations and treatment formulations. Dietary supplementation with fish oils (providing EPA and DHA) appears to alleviate ADHD-related symptoms in at least some children, and one study of DCD children also found benefits for academic achievement. Larger trials are now needed to confirm these findings, and to establish the specificity and durability of any treatment effects as well as optimal formulations and dosages. Omega-3 is not supported by current evidence as a primary treatment for ADHD or related conditions, but further research in this area is clearly warranted. Given their relative safety and general health benefits, omega-3 fatty acids offer a promising complementary approach to standard treatments.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry.

OBJECTIVE: To determine if the available data support the use of omega-3 essential fatty acids (EFA) for clinical use in the prevention and/or treatment of psychiatric disorders. PARTICIPANTS: The authors of this article were invited participants in the Omega-3 Fatty Acids Subcommittee, assembled by the Committee on Research on Psychiatric Treatments of the American Psychiatric Association (APA). EVIDENCE: Published literature and data presented at scientific meetings were reviewed. Specific disorders reviewed included major depressive disorder, bipolar disorder, schizophrenia, dementia, borderline personality disorder and impulsivity, and attention-deficit/hyperactivity disorder. Meta-analyses were conducted in major depressive and bipolar disorders and schizophrenia, as sufficient data were available to conduct such analyses in these areas of interest. CONSENSUS PROCESS: The subcommittee prepared the manuscript, which was reviewed and approved by the following APA committees: the Committee on Research on Psychiatric Treatments, the Council on Research, and the Joint Reference Committee. CONCLUSIONS: The preponderance of epidemiologic and tissue compositional studies supports a protective effect of omega-3 EFA intake, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in mood disorders. Meta-analyses of randomized controlled trials demonstrate a statistically significant benefit in unipolar and bipolar depression (p = .02). The results were highly heterogeneous, indicating that it is important to examine the characteristics of each individual study to note the differences in design and execution. There is less evidence of benefit in schizophrenia. EPA and DHA appear to have negligible risks and some potential benefit in major depressive disorder and bipolar disorder, but results remain inconclusive in most areas of interest in psychiatry. Treatment recommendations and directions for future research are described. Health benefits of omega-3 EFA may be especially important in patients with psychiatric disorders, due to high prevalence rates of smoking and obesity and the metabolic side effects of some psychotropic medications.

Epidemiologic Studies↗
PubMed2005

The Oxford-Durham study: a randomized, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder.

BACKGROUND: Developmental coordination disorder (DCD) affects approximately 5% of school-aged children. In addition to the core deficits in motor function, this condition is associated commonly with difficulties in learning, behavior, and psychosocial adjustment that persist into adulthood. Mounting evidence suggests that a relative lack of certain polyunsaturated fatty acids may contribute to related neurodevelopmental and psychiatric disorders such as dyslexia and attention-deficit/hyperactivity disorder. Given the current lack of effective, evidence-based treatment options for DCD, the use of fatty acid supplements merits investigation. METHODS: A randomized, controlled trial of dietary supplementation with omega-3 and omega-6 fatty acids, compared with placebo, was conducted with 117 children with DCD (5-12 years of age). Treatment for 3 months in parallel groups was followed by a 1-way crossover from placebo to active treatment for an additional 3 months. RESULTS: No effect of treatment on motor skills was apparent, but significant improvements for active treatment versus placebo were found in reading, spelling, and behavior over 3 months of treatment in parallel groups. After the crossover, similar changes were seen in the placebo-active group, whereas children continuing with active treatment maintained or improved their progress. CONCLUSIONS: Fatty acid supplementation may offer a safe efficacious treatment option for educational and behavioral problems among children with DCD. Additional work is needed to investigate whether our inability to detect any improvement in motor skills reflects the measures used and to assess the durability of treatment effects on behavior and academic progress.

Attention Deficit Disorder with Hyperactivity↗
PubMed2004

Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders.

Both omega-3 and omega-6 long-chain PUFA (LC-PUFA) are crucial to brain development and function, but omega-3 LC-PUFA in particular are often lacking in modern diets in developed countries. Increasing evidence, reviewed here, indicates that LC-PUFA deficiencies or imbalances are associated with childhood developmental and psychiatric disorders including ADHD, dyslexia, dyspraxia, and autistic spectrum disorders. These conditions show a high clinical overlap and run in the same families, as well as showing associations with various adult psychiatric disorders in which FA abnormalities are already implicated, such as depression, other mood disorders, and schizophrenia. Preliminary evidence from controlled trials also suggests that dietary supplementation with LC-PUFA might help in the management of these kinds of childhood behavioral and learning difficulties. Treatment with omega-3 FA appears most promising, but the few small studies published to date have involved different populations, study designs, treatments, and outcome measures. Large-scale studies are now needed to confirm the benefits reported. Further research is also required to assess the durability of such treatment effects, to determine optimal treatment compositions and dosages, and to develop reliable ways of identifying those individuals most likely to benefit from this kind of treatment. Childhood developmental and psychiatric disorders clearly reflect multifactorial influences, but the study of LC-PUFA and their metabolism could offer important new approaches to their early identification and management. Heterogeneity and comorbidity are such, however, that a focus on specific traits or symptoms may prove more fruitful than an exclusive reliance on current diagnostic categories.

Brain↗
PubMed2004

Two visual motion processing deficits in developmental dyslexia associated with different reading skills deficits.

Developmental dyslexia is associated with deficits in the processing of visual motion stimuli, and some evidence suggests that these motion processing deficits are related to various reading subskills deficits. However, little is known about the mechanisms underlying such associations. This study lays a richer groundwork for exploration of such mechanisms by more comprehensively and rigorously characterizing the relationship between motion processing deficits and reading subskills deficits. Thirty-six adult participants, 19 of whom had a history of developmental dyslexia, completed a battery of visual, cognitive, and reading tests. This battery combined motion processing and reading subskills measures used across previous studies and added carefully matched visual processing control tasks. Results suggest that there are in fact two distinct motion processing deficits in developmental dyslexia, rather than one as assumed by previous research, and that each of these deficits is associated with a different type of reading subskills deficit. A deficit in detecting coherent motion is selectively associated with low accuracy on reading subskills tests, and a deficit in discriminating velocities is selectively associated with slow performance on these same tests. In addition, evidence from visual processing control tasks as well as self-reports of ADHD symptoms suggests that these motion processing deficits are specific to the domain of visual motion, and result neither from a broader visual deficit, nor from the sort of generalized attention deficit commonly comorbid with developmental dyslexia. Finally, dissociation between these two motion processing deficits suggests that they may have distinct neural and functional underpinnings. The two distinct patterns of motion processing and reading deficits demonstrated by this study may reflect separable underlying neurocognitive mechanisms of developmental dyslexia.

Adult↗
PubMed2003

The perception of "sine-wave speech" by adults with developmental dyslexia.

Numerous studies have shown that, as a group, children or adults with developmental dyslexia perceive isolated syllables or words abnormally. Continuous speech containing reduced acoustic information also might prove perceptually difficult to such listeners. They might, however, exploit the intact syntactic and semantic features present in whole utterances, thereby compensating fully for impaired speech perception. "Sine-wave speech" sentences afford a test of these competing possibilities. The sentences contain only 4 frequency-modulated sine waves, lacking many acoustic cues present in natural speech. Adults with and without dyslexia were asked to orally reproduce 9 sine-wave utterances, each occurring in 4 immediately successive trials. Participants with dyslexia reported fewer words than did control listeners. Practice, phonological contrasts, and word position affected both groups similarly. Comprehension of sine-wave sentences seems impaired in many, but not all, adults with dyslexia. A reduced auditory memory capacity may contribute to this deficit.

Adult↗
PubMed2002

MRI and neuropsychological improvement in Huntington disease following ethyl-EPA treatment.

A 6-month randomized, placebo-controlled pilot study of the ethyl-ester of eicosapentaenoic acid (ethyl-EPA) was carried out in seven in-patients with advanced (stage III) Huntington's disease (three on ethyl-EPA, four on placebo; no significant difference in age or sex between the groups). After 6 months all the patients treated with ethyl-EPA improved on the orofacial component of the Unified Huntington's Disease Rating Scale while all the patients on placebo deteriorated on this scale (p < 0.03). Following subvoxel registration of follow-up 3D MRI brain scans with baseline scans, subtraction images showed that while the placebo was associated with progressive cerebral atrophy, the ethyl-EPA was associated with a reverse process. We conclude that treatment with ethyl-EPA is associated with beneficial motor and MRI changes.

Aged↗
PubMed2002

A volumetric biochemical niacin flush-based index that noninvasively detects fatty acid deficiency in schizophrenia.

(1) It is possible to investigate aspects of phospholipid-related signal transduction in humans noninvasively using the niacin skin flush test. (2) Patients with schizophrenia have previously been reported to show a reduced flushing response. (3) The aim of this study was to devise a comprehensive index of cutaneous response to the niacin test, incorporating aqueous methyl nicotinate concentration and time, and to test this index in schizophrenia. (4) A discrete approximation to a continuous volumetric index, which we have named the volumetric niacin response (VNR), was devised. Its value was measured in 27 patients with DSM-IV schizophrenia and 26 age- and sex-matched normal controls. (5) The mean value of the VNR in the patients with schizophrenia (16.26) was significantly smaller than that of 26.77 in the normal controls (P<.0004). (6) With a threshold value for the VNR of 21, the test differentiated well between schizophrenia and normal controls (P=.002) with a sensitivity of 78% and a specificity of 65%. (7) The present results confirm that the flushing response is reduced in schizophrenia, and show that calculation of the VNR is an effective means of allowing the total response in different patients or patient groups to be readily compared.

Adult↗
PubMed2002

A randomized double-blind, placebo-controlled study of the effects of supplementation with highly unsaturated fatty acids on ADHD-related symptoms in children with specific learning difficulties.

(1) The authors tested the prediction that relative deficiencies in highly unsaturated fatty acids (HUFAs) may underlie some of the behavioral and learning problems associated with attention-deficit/hyperactivity disorder (ADHD) by studying the effects of HUFA supplementation on ADHD-related symptoms in children with specific learning difficulties (mainly dyslexia) who also showed ADHD features. (2) Forty-one children aged 8-12 years with both specific learning difficulties and above-average ADHD ratings were randomly allocated to HUFA supplementation or placebo for 12 weeks. (3) At both baseline and follow-up, a range of behavioral and learning problems associated with ADHD was assessed using standardized parent rating scales. (4) At baseline, the groups did not differ, but after 12 weeks mean scores for cognitive problems and general behavior problems were significantly lower for the group treated with HUFA than for the placebo group; there were significant improvements from baseline on 7 out of 14 scales for active treatment, compared with none for placebo. Group differences in change scores all favored HUFA, reaching conventional significance levels for 3 out of 14 scales. (5) HUFA supplementation appears to reduce ADHD-related symptoms in children with specific learning difficulties. Given the safety and tolerability of this simple treatment, results from this pilot study strongly support the case for further investigations.

Attention Deficit Disorder with Hyperactivity↗