Children with heavy prenatal alcohol exposure exhibit deficits when regulating isometric force.
BACKGROUND
Production of isometric (i.e., constant) force is an essential component of performing everyday functional tasks, yet no studies have investigated how this type of force is regulated in children with confirmed histories of heavy prenatal alcohol exposure.


METHODS
Children 7 to 17 years old with heavy prenatal alcohol exposure (n = 25) and without exposure (n = 18) applied force to a load cell to generate an isometric force that matched a criterion target force displayed on a computer monitor. Two levels of target force were investigated in combination with 3 levels of visual feedback frequency that appeared on the computer monitor as a series of yellow dots. Force was maintained for 20 seconds and participants completed 6 trials per test condition.


RESULTS
Root-mean-square error, signal-to-noise ratio, and sample entropy indexed response accuracy, response variability, and signal complexity, respectively. The analyses revealed that in comparison with controls, children with gestational ethanol exposure were significantly less accurate and more variable in regulating their force output and generated a response signal with greater regularity and less complexity in the time domain.


CONCLUSIONS
Children with prenatal alcohol exposure experience significant deficits in isometric force production that may impede their ability to perform basic motor skills and activities in everyday tasks.
Motor Control Laboratory, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California 92182, USA. rsimmons@mail.sdsu.edu
Roger W
RW
Simmons
Tanya T
TT
Nguyen
Susan S
SS
Levy
Jennifer D
JD
Thomas
Sarah N
SN
Mattson
Edward P
EP
Riley
D000293:Adolescent; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D002648:Child; D003627:Data Interpretation, Statistical; D019277:Entropy; D000431:Ethanol / Q000009:adverse effects*; D005006:Ethnicity; D030141:Feedback, Psychological; D005260:Female; D063647:Fetal Alcohol Spectrum Disorders / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D016018:Least-Squares Analysis; D008297:Male; D009048:Motor Skills / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010775:Photic Stimulation; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D059629:Signal-To-Noise Ratio
D002492:Central Nervous System Depressants; D000431:Ethanol