Problems with language and symptoms of attention-deficit/hyperactivity disorder (ADHD) in childhood and adolescence are often strongly linked to low scholastic performance. Early recognition of children who are at increased risk is necessary. Our objective was to determine whether mixed-handedness, which is associated with atypical cerebral laterality, is associated with language, scholastic, and ADHD symptoms in childhood and adolescence.
Prospective data come from the Northern Finland Birth Cohort 1986, a longitudinal, population-based birth cohort with assessments when children were 7 to 8 and 16 years of age (N = 7871). Teacher, parent, and/or adolescent reports were used to assess language difficulties, scholastic performance, and mental health, including ADHD symptoms.
Mixed-handed children, relative to right-handed, had approximately a twofold increase in odds of having difficulties with language and scholastic performance at the age of 8 years. Eight years later, as 16-year-olds, adolescents had twofold increase in odds concerning difficulties in school with language and with ADHD symptoms. Mixed-handed children were more likely to have scores indicating probable psychiatric disturbance, including ADHD symptoms. As adolescents, mixed-handed children with previous behavioral problems were at considerably higher risk for scoring within the range of probable ADHD-inattention or ADHD-combined case. Mixed-handedness was associated with greater symptom severity in children and adolescents (P = .01) concerning psychiatric disturbance and ADHD inattention but not ADHD hyperactivity.
The results indicate that mixed-handed children have a greater likelihood of having language, scholastic, and mental health problems in childhood and that these persist into adolescence. Thus, these results suggest that mixed-handedness, particularly in the presence of difficulties, could aid in the recognition of children who are at risk for stable problems. Additional research is needed to understand the connections between neural substrates related to atypical cerebral asymmetry, mixed-handedness, and mental health problems including ADHD symptoms.
Comments
Mixed Dominance and Psychiatric Disturbance: Absolute vs Relative Risk
In "Mixed-handedness is linked to mental health problems in children and adolescents," Dr Rodriguez concludes that “mixed-handed children have a greater likelihood of having mental health problems,” that “mixed handedness can be used as a marker of risk … and warrants additional evaluation, and that, “mixed-handedness … is associated with increased risk for behavioral problems.” As noted in the AAP “Smart Brief” of January 28, Reuters reported her findings, “these mixed-handed kids also show more signs of psychiatric disturbance….”
These conclusions are based on the relative risk, but the absolute risk of a child at age 8 with mixed-dominance developing a “psychiatric disturbance” is shown in this 2X2 table.
Psych disturbance +
Psych disturbance -
Totals
Mixed dominance +
18
64
82
Mixed dominance -
931
6069
7000
Totals
949
6133
7082
The sensitivity of mixed dominance for a psychiatric disturbance is 18/949=1.8%; its positive predictive value is 22%.
The prior probability for a psychiatric disturbance is 949/7082= 13.4%. Thus the absolute risk difference is about 8%. So, how “harmful” is it for a child to have mixed-dominance? The NNH (number needed to harm) is the reciprocal of 8%. About 12 children with mixed dominance would need to have “additional evaluation” to detect one child with a psychiatric disturbance.
Reuters quotes Dr. Rodriguez as saying, "If a child is mixed handed I wouldn't worry if there are no other problems whatsoever. But if there are "red flags" like ADHD in the family or behavioral and learning problems, I think it's worth having extra evaluation for the child." I could not find that caveat in the article in Pediatrics.
It is true that 22% is almost double 13%, but isn’t it relevant to mention that 64 of the 82 (78%) children with mixed-dominance had no psychiatric disturbance just as 6069 of the 7000 (87%) right handed children did not? Perhaps it would be more productive to evaluate the undisturbed 64 children to see how they differed from the 18 who were less fortunate rather than to assert that detecting mixed dominance is important for “early detection of risk.”
Conflict of Interest:
None declared
Handedness and Delacato Movement therapy
Following the publication in Pediatrics, published on line January 25th, 2010, DOI: 10.1542/peds.2009-1165, Rodriguez, A, et al, “Mixed- handedness is Linked to Mental Health Problems in Children and Adolescents”, it is ironic to say the least that the same Journal which spent 40 years in endeavoring to repudiate the work of Fay, Doman and Delacato, publishes a paper which actually affirms the principles from which their therapy arose. Their conclusion reads, “Our study shows that mixed-handedness is associated with concurrent impairments and, more importantly, is related to increased risk in late adolescence for language difficulties and ADHD” The American Academy of Pediatrics (AAP), published in 1968 their Policy Statement, reaffirmed their statement in 1982, and published in Pediatrics Vol. 104 No 5 November 1999, pp.1149-1151; entitled “The Treatment of Neurologically impaired Children Using Patterning.” The statement was issued by the AAP, as a result of the work being carried out by the team, led by Dr Temple Fay, which included Dr Carl Delacato, and Drs Robert and Glen Doman, at the Institute for the achievement of Human Potential in Philadelphia. The statement in effect was a criticism of the work of the Institute, and after more than 40 years the stance of the AAP has remained. The Autism Centre has over the last 5 years has published a number of articles relating to the work of the Institute, in principle the work known as Doman-Delacato Therapy, eventually Delacato working individually, on the therapy of Neurologically Dysfunctional individuals, with mild diffuse brain injury , and lack of hemispherical dominance affecting their learning ability and behavioural problems. The criticism as stated by the AAP is as follows,” Neurologic organization, the principle central to the patterning theory of brain functioning, is an oversimplified concept of hemispheric dominance and the relationship of individual sequential phylogenetic development. This theory also states that failure to complete properly any stage of neurologic organization adversely affects all subsequent stages and that the best way to treat a damaged nervous system is "to regress to more primitive modes of function and to practice them." According to this theory, the majority of cases of mental retardation, learning problems, and behavior disorders are caused by brain damage or improper neurologic organization, and these problems lie on a single continuum of brain damage, for which the most effective treatments are those advocated by patterning. Current information does not support these contentions. In particular, the lack of dominance or sidedness probably is not an important factor in the cause of, or the therapy for, these conditions. Several careful reviews of the theory have concluded that it is unsupported, contradicted, or without merit based on scientific study. Others have described the hypothesis of neurologic organization to be without merit and concluded that the theoretical rationale for the treatment is inconsistent with accepted views of neurologic development. “ Perhaps now the AAP will accept that they have spent the last 40 years in a fruitless effort, only succeeding in denying many individuals the opportunity for some degree of rehabilitory occupational and physiotherapy by their relentless pursuit of a group of individuals whose only intention was to provide a service to those with a disability and never themselves made any effort to afford a similar assistance. Yours, Robin Burn I Eng. FIMMM The Autism Centre www.theautismcentre.co.uk
Conflict of Interest:
None declared