J Manipulative Physiol Ther. 2009 (Oct); 32 (8): 660–669 ~ FULL TEXT
Cuthbert SC, Barras M.
Chiropractic Health Center,
Pueblo, CO 81004, USA.
OBJECTIVE: This study presents a case series of 157 children with developmental delay syndromes, including the conditions such as dyspraxia, dyslexia, attention-deficit hyperactivity disorder, and learning disabilities who received chiropractic care.
CLINICAL FEATURES: A consecutive sample of 157 children aged 6 to 13 years (86 boys and 71 girls) with difficulties in reading, learning, social interaction, and school performance who met these inclusion criteria were included.
INTERVENTION AND OUTCOMES: Each patient received a multimodal chiropractic treatment protocol, applied kinesiology chiropractic technique. The outcome measures were a series of 8 standardized psychometric tests given to the children by a certified speech therapist pre- and posttreatment, which evaluate 20 separate areas of cognitive function, including patient- or parent-reported improvements in school performance, social interaction, and sporting activities. Individual and group data showed that at the end of treatment, the 157 children showed improvements in the 8 psychometric tests and 20 areas of cognitive function compared with their values before treatment. Their ability to concentrate, maintain focus and attention, and control impulsivity and their performance at home and school improved.
CONCLUSIONS: This report suggests that a multimodal chiropractic method that assesses and treats motor dysfunction reduced symptoms and enhanced the cognitive performance in this group of children.
From the FULL TEXT Article
Chiropractic treatment of developmental delay syndromes (DDSs), a term that encompasses conditions such as dyspraxia, dyslexia, learning disabilities, and attention-deficit hyperactivity disorder (ADHD), has shown some interest.  The need for more observational and experimental studies in this area has also been pointed out. 
It has been shown that motor discoordination, especially affecting the postural and ocular muscles, is a common comorbid condition associated with this spectrum of disorders. [3–7]
At this time, DDSs are thought to have multifactorial etiologies. [3, 4, 8–11] The epidemiologic prevalence of these disturbances has been estimated to be as high as 5% to 20% (depending on a conservative definition). [10, 11]
Over the past decade, there has been an increase in the number of DDS-related visits to health care providers, and the percentage of children with severe behavioral and language problems is increasing.  A study by the US Department of Education stated that more than 50% of minority and nonminority children are not reading at their grade level.  With the increase of methylphenidate use by 700% since 1990,  and because last year, doctors in the United States wrote an estimated 20 million prescriptions for methylphenidate, it is obvious why parents and children with DDS come to chiropractors and other physicians for help.
In a survey of children with DDS (specifically ADHD), 67.6% of families reported current or past use of complementary and alternative medicine to manage this condition, including chiropractic, modified diet, and vitamins, minerals, and dietary supplements.  The natural history of DDS is also a challenge. Medications are often used for these children, but these medications do not necessarily normalize these children's function.  In children treated pharmacologically, subtle and not-so-subtle neurocognitive impairments often persist into adulthood. [16–19] Problems with DDS are likely to affect employment status, educational achievements, health care consumption, traffic and other accidents, and criminality.
A growing body of research evidence has found that poor muscle tone is related to postural disorders, sensory-motor and coordination disorders, and kinesthesia in children with DDS. [3–5, 20–22]
Although it has been fairly well known that attention deficit disorder and ADHD, for instance, are comorbid with other psychiatric disorders, what is less well known and more significant to the present study is the association between ADHD and motor control dysfunctions, or what has been termed developmental coordination disorder or dyspraxia. [3–5, 21, 22]
Because motor and cognitive functions often coexist, this study was undertaken to investigate whether chiropractic assessment and treatment of motor impairments in 157 children with DDS would have positive effects upon their cognitive performance. We used widely accepted and standardized assessment tools from the educational psychology and logopedic (speech therapy) fields. This report offers a standardized, quantitative data collection system for a consecutive sample of 157 children with DDS.
The complexity of the findings in these cases confirms the findings of other researchers who have suggested that DDS is complex and multifactorial, and this is one of the reasons why many aspects of diagnosis and treatment must be highly individualized if they are to be successful. 
The natural history of DDS shows that this condition often persists into adulthood. [17–19] Children with language, reading, coordination, and behavioral disorders show that without treatment, these problems persist into adulthood.  There is a prevalence of 4% among adults in the United States, and this condition was found to preexist during the childhood of those surveyed. 
Developmental Delay Syndrome Linked to Motor Impairments
A new school of thought in the treatment of these children suggests that there may be a common factor between these various kinds of DDS. Lesser known than learning disability, ADHD and dyslexia, dyspraxia (also known as developmental coordination disorder) affects as many as 5 to 10% of children between the ages of 5 and 11 years, with 2% of children affected severely.  Epidemiologically, the statistical equivalence between DDS and dyspraxia, and its comorbidity with DDS, is noteworthy. [5–7, 10–12, 22]
Dyspraxia is a disorder of praxis, the Greek word meaning doing, acting, and practice. Praxis includes both knowing what to do and how to do it—doing something with ease and without effort. A child's development is generally inferred from his motor actions or praxis, for that is the dimension most easily available for observation and testing.
An important article by Piek and Dyck  relevant to the findings in this report shows that children who have been diagnosed with any one developmental disorder are very likely to meet diagnostic criteria for some other developmental disorder. Based on a critical examination of relevant literature and their own research findings, Piek and Dyck found that the importance of poor motor functioning in discriminating children with different developmental disorders has been underestimated.  Piek and Dyck found that dyspraxia, or poor sensory-motor coordination, is very frequently the common denominator linking dyslexia, learning disabilities, and ADHD. The most common symptoms seen in these children involve the muscles—low muscle strength, lack of coordination, clumsiness, bad posture, and an awkward gait. If these conditions are so frequently present together in one child, perhaps they are really all the same condition. [5, 9, 22, 66]
Yan et al  also conducted a meta-analysis suggesting that both from a theoretical and a practical viewpoint, understanding the influence of motor function on child development is crucial for parents, educators, and researchers.
Because motor dysfunction, and specifically muscular inhibition, has been found as a very common comorbidity associated with DDS, a reliable clinical tool for the diagnosis of this muscular inhibition is desirable. The best tests for children are those that are safe, reliable, and valid. Poor motor performance is most practically assessed in the clinic using the MMT.
In addition, the ability to differentiate between the muscular, mechanoreceptor, vestibular, or visual contributions to postural control and motor performance may have been critical to the successes achieved in this series of cases.  This kind of evaluation may help in determining the precise source of the problem inhibiting sensory-motor integration.
A growing number of studies have also shown that there is an immediate effect upon the motor system after CMT, [68–72] and the use of CMT for the correction of motor deficits found in children with DDS was the rationale for the present study.
Although pharmacologic agents have proven effective in improving some of the symptoms of DDS, there are justifiable concerns about the long-term use of stimulant and antidepressant medications in children with these disorders. Medications such as methylphenidate are a class II controlled substance, and several prominent researchers have, over recent years, raised concerns that it might be a classic “gateway” drug, opening the door to abuse of other substances. (Methylphenidate trading is rampant at select high schools. )
The clinical and psychometric testing outcomes reported here after CMT must now be compared with the clinical outcomes reported in the literature after treatments by stimulant medications. [16–19]
Developmental Delay Syndrome and Psychometric Testing in the Chiropractic Literature
Previous attempts to evaluate manual and manipulative treatment for children with dyspraxia, learning disability, ADHD, and dyslexia with psychometric testing methods have been reported.
In 1999, Mathews et al  conducted a controlled clinical trial on the AK treatment of 10 children with learning disabilities and 10 untreated children with learning disabilities. An educational psychologist matched the control group to the treatment group for age, IQ, and social background. Examination involved AK MMT techniques with the educational psychologist using the Wechsler Intelligence Scale for Children, a standardized test of intelligence to monitor changes in their learning skills before and after treatment. The psychologist's assessment showed that the children treated with AK chiropractic methods experienced significant improvements in their learning abilities during the course of 9 to 12 treatment sessions for a 6– to 12–month period.
A recent narrative literature review by Pauli  regarding the AK concepts and the clinical research articles regarding DDS were published. Ferrari and Wainwright  are 2 clinicians whose work comes from AK who have written a book, which includes numerous case reports on the chiropractic treatment of dyslexia and learning disabilities using AK methods.
Brzozowske and Walton [77, 78] also used psychometric testing pre- and posttreatment to monitor the effect of chiropractic care of children with DDS, showing positive outcomes.
Limitations to this study are the heterogeneity of the sample and that there was no blinding of the treating doctor or the logopedist. Furthermore, no control group or randomization of testing or treatment sequence was used. As a case series, the external applicability of the findings from this report must be viewed with caution.
The differing length of treatment for these children also adds to the difficulty of interpretation of the results reported. However, the natural history of DDS does not suggest that within 5 days and up to 18 months without treatment, significant changes such as those reported here occur for these children. The use of a consecutive sample was appropriate because it evaluated whether CMT would be effective for the types of children with DDS who are brought to a chiropractor for care. The use of a consecutive sample also reduced bias in the selection of patients because all patients who came for care were admitted if they met the inclusion criteria.
Developmental delay syndrome is an increasingly common neurologic and behavioral condition that has a detrimental impact on the children affected and their families. Because the etiology is still uncertain, research continues to identify factors that play roles in this condition.
The relationship between improvements in standardized psychometric test scores (tests that were given immediately pre- and posttreatment), the improvements in this cohorts' cognitive and social behavior with their family and at school, and the improvement in MMT findings on AK examination suggests there may be a relationship between the chiropractic intervention provided and the improved status in these children. Because there was no control group for this in-office clinical trial, we must be cautious, however, about casually extending these results outside this treatment setting.
Every patient with DDS in this report showed dysfunction of their motor system (determined by the MMT), a finding in agreement with the previous literature cited showing muscle weakness and coordination impairments to be the most common factor in these children. The establishment of a chiropractic literature base for the effect of chiropractic treatment on children with DDS using psychometric testing has commenced with case studies, progressed to larger case series reports such as this one, and ultimately must progress to randomized controlled trials.
Even though the responsible doctor of chiropractic would not claim that chiropractic care is the only health care that children with DDS may require, the available research literature as well as this case series report does suggest a possible role for chiropractic care for this population.
Developmental delay syndromes (DDS) encompass the conditions known as dyspraxia, dyslexia, learning disabilities, and attention-deficit hyperactivity disorder.
The most common feature in DDS is motor impairments.
Psychometric testing evaluating cognitive function showed good improvements after chiropractic manipulative treatment in children with DDS.
The suggested link between motor impairments and DDS described in the literature and the muscle inhibitions found with manual muscle testing in this group of children was confirmed.