.
Links
Overflow movements predict impaired response
inhibition in children with ADHD.
Mostofsky SH, Newschaffer CJ, Denckla MB.
Kennedy Krieger Institute, Department of Neurology, Johns
Hopkins University School of Medicine, Baltimore, MD 21205,
USA. mostofsky@kennedykrieger.org
Neurologic models proposed to explain mechanisms underlying
ADHD have emphasized deficits in response inhibition. Ageinappropriate overflow movements, e.g., mirror movements, are
motor signs thought to reflect immaturity in cortical systems
involved in automatically (unconsciously, without explicit effort)
inhibiting extraneous movement. We investigated the hypothesis
that the presence of excessive overflow movements would
predict measures of conscious, effortful response inhibition
(conflicting and contralateral motor response tests) in children
with ADHD. 42 children with ADHD and 30 controls, ages 8
through 12 years, participated. Children with ADHD showed
significantly more overflow movements than did controls and
made more errors on the conflicting and contralateral motor
response tests. Multiple linear regression analysis indicated that
overflow movements predicted performance on measures of
motor response inhibition. For one of those measures, the
contralateral motor response test, there was a significant
interaction with diagnosis, such that overflow predicted
response inhibition in ADHD but not in controls. The findings
suggest that overflow movements, which can be readily
observed as part of clinical examination, are more evident in
children with ADHD. Positive correlations between measures of
overflow movements and measures of response inhibition
suggest that closely associated neural mechanisms underlie
these deficits and support hypotheses that age-inappropriate
overflow reflects immaturity of cortical systems involved in
automatic inhibition.
PMID: 15002876 [PubMed - in process]
Related Articles, Links
1: Rev Neurol. 1999 Oct 16-31;29(8):731-5
[Congenital mirror movements. Three new cases of a rare
condition]
[Article in Spanish]
Ruggieri V, Amartino H, Fejerman N.
Servicio de Neurologia, Hospital Nacional de Pediatria J.P.
Garrahan, Buenos Aires, Argentina. vruggieri@intramed.net.ar
INTRODUCTION: Mirror movements (MM) are involuntary
shudders which occur at the same time as voluntary movements
of the homologous contralateral muscles. They may occur alone
or associated with other pathology. CLINICAL CASES: We present
three new cases of congenital MM (CMM) and discuss their
clinical, physiopathological and genetic aspects. Case 1. A four
year old boy was brought to the clinic because he dropped
things held in one hand when he tried to take things with the
other. On examination it was seen that when he made a
voluntary movement with one hand, the other hand made a
similar movement simultaneously and involuntarily. This
phenomenon had been observed since he was a few months old.
Apart from this, the rest of the neurological examination was
normal. Cerebral MR was also normal. Neuropsychological
assessment showed borderline intellectual function. Case 2. The
first patient's father, who was 26 years old, knew no details of
his own family history. Since childhood he had noticed that he
himself had made similar movements to those of his son.
However, with time, he had managed to partially control and
even inhibit these movements. His cerebral MR scan was normal.
Case 3. An 11 year old boy consulted for MM, non-fluctuating
congenital palpebral ptosis and nocturnal enuresis. The
neurological examination and his intelligence were found to be
normal. One of his sisters had palpebral ptosis and nocturnal
enuresis without MM. His cerebral MR, X-ray of his spine, EMG,
electroretinogram, CPK, blood lactate, glucemia, urine and
urological examination were normal. CONCLUSIONS: MM may be
another manifestation within the clinical spectrum of diverse
encephalopathies; may be associated with different syndromes
(Kallman, Klippel-Feil and Usher amongst others) or may present
alone. Both familial and sporadic cases have been described. We
consider our cases 1 and 2 to be of the familial CMM condition,
with autosomal dominant inheritance, in which MM was the only
finding. The association observed in case 3 has not previously
been described. It may possibly be a condition transmitted by
autosomal recessive inheritance.
Publication Types:

Case Reports
PMID: 10560107 [PubMed - indexed for MEDLINE]
1: Dev Med Child Neurol. 1993 Aug;35(8):699-707.
Related Articles, Links
Persistent mirror movements: a clinical study of 17
children, adolescents and young adults.
Rasmussen P.
Child Neuropsychiatric Clinic, University of Goteborg, Sweden.
The author reports a series of 17 cases of congenital mirror
movements of the hands and forearms (and in a few cases the
toes), but no other signs of gross neurological deviation. This is
an uncommon disorder that often goes unrecognised. This
slight but definite disability seems to persist largely unchanged
at least into the late teens, and probably into adulthood. A
hereditary background is suggested in about half of the cases.
Various neuropsychiatric deficits were seen in combination with
the mirror movements in about half the cases, as well as a high
incidence of non-right-handedness. Although the clinical
heterogeneity of the disorder was clear, the phenomenon of
mirror movements was similar in all cases. Recent progress in
understanding the pathophysiology of this disorder is reviewed.
Publication Types:

Case Reports

Review

Review of Reported Cases
PMID: 8335159 [PubMed - indexed for MEDLINE]