Electrical impedance myography in the assessment of disuse atrophy.
Tarulli AW, Duggal N, Esper GJ, Garmirian LP, Fogerson PM, Lin CH, Rutkove SB. Electrical impedance myography in the assessment of disuse atrophy.


OBJECTIVE
To quantify disuse atrophy using electrical impedance myography (EIM), a noninvasive technique that we have used successfully to study neurogenic and myopathic atrophy.


METHODS
We performed EIM of the tibialis anterior of subjects with disuse atrophy secondary to cast immobilization and in their contralateral normal leg. Subjects were studied shortly after cast removal and again several weeks to months after the cast was removed and normal mobility was restored.


METHODS
Outpatient neurology and orthopedic practices at a tertiary care medical center.


METHODS
Otherwise healthy subjects (N=10) with unilateral leg fracture.


METHODS
Not applicable.


METHODS
Resistance, reactance, and phase measured at 50kHz.


RESULTS
The main EIM outcome parameter, phase at 50kHz, was lower in the immobilized leg in 9 of 10 cases. Additionally, when normal mobility was restored, the phase of the casted leg increased relative to its initial measurement in all 10 cases, while it increased inconsistently in the contralateral leg.


CONCLUSIONS
EIM may be a powerful tool for the assessment of disuse atrophy.
Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
Andrew W
AW
Tarulli
Naven
N
Duggal
Gregory J
GJ
Esper
Lindsay P
LP
Garmirian
Patricia M
PM
Fogerson
Connie H
CH
Lin
Seward B
SB
Rutkove
D000328:Adult; D017097:Electric Impedance; D004576:Electromyography; D005260:Female; D005592:Fracture Fixation; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D020966:Muscular Disorders, Atrophic / Q000503:physiopathology*