Neurofeedback, also known as EEG (electroencephalogram)biofeedback, is a treatment that seeks to alleviate symptoms of various neurological and mental health disorders, including ADHD. It does this through immediate feedback from a computer program that tracks a client’s brainwave activity, then uses sound or visual signals to retrain these brain signals. This in principle enables patients to learn to regulate and improve their brain function and reduce symptoms.
An Iranian study team recently performed a systematic search of the peer-reviewed medical literature. It identified seventeen randomized-controlled trials (RCTs) of neurofeedback treatment for children and adolescents with ADHD that could be aggregated for meta-analysis.
A meta-analysis of twelve RCTs with a combined total of 740 youths looked at parent ratings of changes in hyperactivity/impulsivity symptoms, and separately of changes in inattention symptoms. In both instances, the net pooled effect centered on zero.
A meta-analysis of nine RCTs with a combined total of 787 youths examined teacher ratings. Once again, the pooled change hyperactivity/impulsivity symptoms centered on zero. For inattention symptoms, the teacher ratings centered on a tiny improvement, but it did not approach statistical significance. The 95% confidence interval stretched well into negative territory.
There was no sign of publication bias. Between-study heterogeneity, on the other hand, was high, with some small sample size RCTs pointing to reduced symptoms, and other small sample size RCTs pointing to increased symptoms. However, the RCTs with the larger sample sizes clustered close around zero effect size.
The authors concluded, “The results provide preliminary evidence that neurofeedback treatment is not an efficacious clinical method for ADHD.â€
Bipolar disorder is a severe mental illness that afflicts over one in fifty persons worldwide. About a quarter of those with bipolar disorder also has alcohol use disorder (AUD). This in turn complicates the treatment of their bipolar disorder. It exacerbates their symptoms, makes them more likely to be suicidal, and increases the risk of hospitalization.
More than one in five persons with bipolar disorder also have ADHD, which is likewise known to be correlated with AUD. To what extent does ADHD contribute to AUD in persons with comorbid bipolar disorder?
A European study team recently conducted a systematic search of the peer-reviewed medical literature to address that question. The team identified eleven studies with a combined total of 2,734 participants that could be aggregated to perform a meta-analysis.
They found that persons with comorbid ADHD and bipolar disorder were two and a half times more likely to be diagnosed with alcohol use disorder than persons with bipolar disorder but no ADHD.
Between-study heterogeneity was negligible, and there was no sign of publication bias.
The authors concluded, “At least a portion of the high rates of AUD in BD may, thereby, be related to comorbid ADHD. Longitudinal studies are needed to clarify the nature of this relationship.â€
Meta-analysis discovers clear link between mothers with PCOS and children with ADHD.
Polycystic ovary syndrome (PCOS) affects somewhere between 6 and 20% of women of reproductive age. Typical effects include:
· failure to ovulate;
· high levels of male hormones (androgens), which can lead to acne, seborrhea, hair loss on the scalp, increased body or facial hair, and infrequent or absent menstruation;
· metabolic disruption, including obesity and insulin resistance.
In pregnancy, PCOS is also known to increase the chances of birth complications.
Previous studies have suggested a link between maternal PCOS and ADHD.
A team of Arabian (Saudi and United Arab Emirates) researchers conducted a systematic review of the peer-reviewed medical literature and were able to identify four studies with a total of 1,354,182 participants that could be combined into a meta-analysis.
The meta-analysis found that children born to mothers with PCOS were 43% more likely to develop ADHD. The 95% confidence interval stretched from 35% to 51%, indicating a highly reliable finding.
Moreover, there was between-study variation: They all produced essentially identical results. There was also no sign of publication bias.
“However,†the authors noted, “the reported results do not necessarily provide definitive findings of a causal inference due to the randomized study design. All the included studies were observational in design.†With this caution, they could only conclude that “the results of this meta-analysis showed that there might be a link between maternal PCOS and the risk of developing ASD and ADHD in the offspring.â€
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Childhood antibiotic use is not found to be associated with development of ADHD
A Chinese research team recently conducted a systematic search of the peer-reviewed medical journal literature for studies exploring the association between childhood antibiotic exposure and subsequent diagnosis of ADHD in youths 18 years and younger.
A meta-analysis of six studies with a combined total of over 1.5 million participants found that children exposed to antibiotics were 18% more likely to later be diagnosed with ADHD.
There was absolutely no indication of publication bias. Between-study heterogeneity, on the other hand, was extremely high.
With such large cohorts, one can often tease out whether an association is causal, or due to genetic and familial confounding, by looking at matched close relatives.
Three of the studies, with a combined total of well over half a million participants, also compared matched siblings.
Significantly, the meta-analysis among matched siblings found no association whatsoever between childhood exposure to antibiotics and subsequent ADHD. Between-study heterogeneity was virtually nonexistent.
The team concluded, “Our meta-analysis indicated that early-life antibiotic exposure was associated with a subsequent increased risk of ASD or ADHD. However, such association was not found in the sibling-matched analysis, indicating that genetic and familial confounding factors may largely explain the observed association.â€
Based on current findings, repetitive transcranial magnetic stimulation cannot yet be officially recommended as an alternative neurotherapy for ADHD.
Noting that “despite a lack of solid evidence for their use, rTMS [repetitive transcranial magnetic stimulation]and tDCS [transcranial direct current stimulation] are already offered clinically and commercially in ADHD,†and that a recent meta-analysis of ten tDCS studies found small but significant improvements in outcomes, but had several methodological shortcomings and did not include two studies reporting mostly null effects, a team of British neurologists performed a meta-analysis of all twelve sham-controlled, non-open-label, studies found in a comprehensive search of the peer-reviewed literature.
Ten of the twelve randomized-controlled trials used anodal stimulation of the dorsolateral prefrontal cortex, while the other two used anodal stimulation of the right inferior frontal cortex.
The trials explored several measures of cognition. The research team carried out a meta-analysis of all twelve trials, with a total of 232 participants, and found no significant improvement in attention scores from CDC, relative to sham stimulation. A second meta-analysis, of eleven trials with a total of 220 participants, assessed the efficacy of tDCS on improving inhibition scores, and again found no significant effect. A third meta-analysis, encompassing eight trials with a total of 124 participants, evaluated the efficacy of tDCS on improving processing speed scores, once again finding no significant effect.
The latter two meta-analyses approached the border of significance, prompting the authors to speculate that larger sample sizes could bring the results just over the threshold of significance. Even so, effect sizes would be small.
It is also possible that the trials focused on regions of the brain suboptimal for this objective, and thus the authors “cannot rule out the possibility that stimulation of other prefrontal regions (such as the right hemispheric inferior frontal cortex or dorsolateral prefrontal cortex or parietal regions), multiple session tDCS or tDCS in combination with cognitive training could improve clinically or cognitive functions in ADHD.â€
As to concerns about safety, on the other hand, “stimulation was well-tolerated overall.â€
The authors concluded that based on current evidence, tDCS of the dorsolateral prefrontal cortex cannot yet be recommended as an alternative Neurotherapy for ADHD.
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According to Dexing Zhang et al., writing in the British Medical Bulletin, “Mindfulness is a moment-by-moment awareness of thoughts, feelings, bodily sensations, and surrounding environment. … These practices can be formal (e.g. breathing, sitting, walking, body scan) or informal (e.g. mindfulness in everyday life).… Mindfulness is rooted in Buddhist traditions. However, it has become popular in recent years among various secular populations in healthcare, educational, and workplace settings: from pre-schoolchildren to older adults across the world.†The two most widely adopted mindfulness-based interventions (MBIs) are mindfulness-based stress reduction and mindfulness-based cognitive therapy (Zhang, 2021).
An Italian research team recently conducted a comprehensive search of the peer-reviewed literature to identify studies exploring the efficacy of mindfulness-based treatments for ADHD. It found 31 studies that qualified for review, ten of which met the criteria for meta-analysis, with a total of 596 participants.
A meta-analysis of seven studies with a combined total of 489 participants found MBIs reduced ADHD symptoms with medium effect size and no sign of publication bias. When split into subgroups with and without active controls – in this case, psychoeducation and skills training groups –the outcomes diverged. In the three studies with non-active controls (187 participants), there was a large reduction in ADHD symptoms. In the four with active controls (302 participants), there was no significant difference.
A meta-analysis of ten studies with 596 participants found MBIs reduced inattention symptoms, with a medium-sized effect. Pooling the five studies without active controls (261 participants) produced a very large reduction in inattention symptoms. Once again, in the five studies with active controls (335 participants), there was no significant difference.
After adjusting for publication bias, a third meta-analysis of nine studies with 563 participants found no significant effect of MBIs hyperactivity symptoms. However, when limited to the five studies with-active controls (261 participants), it found a large reduction in hyperactivity symptoms.
After adjusting for publication bias, the fourth meta-analysis of four studies with a combined 243 participants found no significant improvement in executive function.
After adjusting for publication bias, a fifth meta-analysis combining six studies with 449 participants reported a moderate improvement in mindfulness skills. There was no significant improvement when looking only at the three studies with active controls (262 participants).
The team concluded that MBIs seemed to be effective in treating ADHD, but no more so than psychoeducation and skills training groups.
Yet they cautioned that the use of a waiting list for non-active controls muddies that conclusion: “It could be suggested that any intervention seems to have a significantly higher effect than WL [waiting list]in improving ADHD symptoms.†This is a known hazard of using waiting lists as control groups (Cunningham, 2013).
Noting “the low general methodological quality,†they stated, “From a clinical standpoint, according to the poor available evidence, we cannot conclude that MBIs are superior to other active [psychological] interventions in ameliorating all the considered outcomes, suggesting a role complementation and not as a replacement of the psychoeducation in the management of patients with ADHD, consistently with some guidelines’ recommendations.â€
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Meta-analysis show neurofeedback treatments resulted in no noticeable improvements in the working memory, response inhibition, or sustained attention of youth with ADHD.
Neurofeedback, also known as electroencephalogram (EEG) biofeedback, aims to help persons with ADHD train themselves to self-regulate patterns of brain activity associated with the disorder.
An example is theta-beta ratio frequency (TBR) training. Beta waves, with a frequency of 18 to 25 Hz, are associated with electrical activity when the brain is conscious or alert. Theta waves, with a frequency of 4 to 7 Hz, are associated with meditative, daydreaming, or drowsy states. In youths with ADHD, the theta to beta ratio tends to be elevated. TBR training seeks to reduce it.
Neurofeedback is often described as a promising emerging alternative or complement to pharmaceutical treatment. Previous meta-analyses have found neurofeedback can reduce symptoms of ADHD.
But what effect does it have on executive functions? A Thai research team based at Chiang Mai University conducted a comprehensive search of the peer-reviewed journal literature and identified ten studies with results suitable for meta-analysis.
A meta-analysis of all ten studies with a combined total, of 378 participants found no improvement whatsoever in response inhibition.
A second meta-analysis, of nine studies with a combined total of 349 participants, found no improvement in sustained attention.
Finally, a meta-analysis of three studies with a total of 121 participants likewise found no improvement in working memory.
In all three cases, there was no evidence of publication bias.
The authors concluded, “Results did not show the benefits of neurofeedback on executive functions assessed by neuropsychological tests.â€
