Impact of skin-subcutaneous fat layer thickness on electrical impedance myography measurements: an initial assessment.
OBJECTIVE
To determine the impact of skin-subcutaneous fat layer thickness on electrical impedance myography (EIM) measurements.


METHODS
Linear 50 kHz EIM was performed on quadriceps of 62 healthy subjects (mean age 52.2+/-20.6 years) with a wide variety of skin-subcutaneous fat layer (SFL) thicknesses, as measured by ultrasound. Correlations were sought between the main EIM outcome parameter phase (theta) and SFL thickness. A multiple regression analysis was also performed for theta with SFL thickness and age as independent variables.


RESULTS
Mean skin-fat thickness was significantly different (p<0.01) between men (0.76+/-0.23 cm) and women (1.43+/-0.51 cm). Neither linear nor quadratic fits produced significant correlations between theta and SFL thickness. A significant but weak positive correlation (r(2)=0.14, p<0.05) was seen between age and SFL thickness in women, but not in men. A strong negative correlation between age and theta was observed for both men (r(2)=0.48, p<0.01) and women (r(2)=0.68, p<0.01). In multiple regression analysis, age but not SFL thickness was found to have a significant association with theta.


CONCLUSIONS
SFL thickness does not contribute substantially to the phase measured by linear-EIM.


CONCLUSIONS
EIM data can be interpreted confidently in individuals with varying SFL thickness.
Tarulli
A W
AW
Department of Neurology, Division of Neuromuscular Diseases, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Shapiro 810, Boston, MA 02215, USA.
Chin
A B
AB
Lee
K S
KS
Rutkove
S B
SB
D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D017097:Electric Impedance; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009213:Myography / Q000379:methods; D012044:Regression Analysis; D012737:Sex Factors; D012867:Skin; D012885:Skinfold Thickness; D014463:Ultrasonography / Q000379:methods