U.S. study finds increased prevalence of left-handedness in children with facial development disorder

WASHINGTON, March 2 (Chinese media) -- A new study by physician

researchers from Hasbro Children's Hospital in Rhode Island and Children's

Hospital Boston has identified an increased prevalence in left-handedness

in children with a congenital disorder known as hemifacial

microsomia (HFM).

The study was published in the March 2009 edition of

the Journal of Craniofacial Surgery.

Overall, ten percent of the population is

left-handed. A higher frequency has been associated with certain craniofacial

malformations such as cleft lip and other conditions.

Albert Oh, director of pediatric plastic and

craniofacial surgery at Hasbro Children's Hospital, along with researchers from

Children's Hospital Boston, developed this study to determine if the frequency

of left-handedness increased in patients with HFM.

HFM is the second most common birth defect after

clefts, and is a condition that affects the development of the lower half of the

face. It most commonly affects the ears, mouth or jaw, and can occur on either

side of the face or both.

A total of 86 patients who were diagnosed with HFM

were studied and compared to a control group using several factors. The study

group was 48 percent male, with an average age of 13.5 years. Of those patients,

49 percent had predominant right side involvement of HFM, while 38 percent had

left side involvement and 13 percent had almost equal involvement on both sides.

The control group included 96 children, 44 percent male with a mean age of 10

years.

When compared to the control group, the study group

showed 26 percent were left-hand dominant for writing compared with only 11

percent in the control group. Also of note, for the patients who had bilateral

involvement of their HFM, the side most affected was uniformly predictive of

hand preference. The patients with left-predominant involvement of HFM were

left-handed and the patients with right-predominant involvement were

right-handed.

Albert Oh, who is also a professor of surgery at the

Warren Alpert Medical School of Brown University, says: "This study is

significant in that it revealed a significant shift to left-hand preference in

patients with HFM. This finding further emphasizes that the developmental

abnormality that causes HFM is not isolated to the face."

Oh and the authors also note that the study should

promote further discussion of the two major etiological theories of HFM:

vascular disruption and abnormal proliferation or migration of neural crest

cells (cells located in the neural plate in the embryo that migrate to their

final destinations during embryo development).

The study, while limited in size, found no

correlations between the side of facial involvement and hand preference that

would support the theory of vascular disruption.