Objective: Determine intramuscular fat (IMF) in affected skeletal muscle after complete spinal cord injury using a novel analysis method and determine the correlation of IMF to plasma glucose or plasma insulin during an oral glucose tolerance test. Setting: General community of Athens, GA, USA. Methods: A total of 12 nonexercise-trained complete spinal cord injured (SCI) persons (10 males and two females 40712 years old (mean7SD), range 26-71 years, and 875 years post SCI) and nine nonexercise-trained nondisabled (ND) controls 2979 years old, range 23-51 years, matched for height, weight, and BMI, had T 1 magnetic resonance images of their thighs taken and underwent an oral glucose tolerance test (OGTT) after giving consent. Results: Average skeletal muscle cross-sectional area (CSA) (mean7SD) was 58.6721.6 cm 2 in spinal cord subjects and 94.1732.5 cm 2 in ND subjects. Average IMF CSA was 14.576.0 cm 2 in spinal cord subjects and 4.772.5 cm 2 in nondisabled subjects, resulting in an almost four-fold difference in IMF percentage of 17.374.4% in spinal cord subjects and 4.672.6% in nondisabled subjects. The 60, 90 and 120 min plasma glucose or plasma insulin were higher in the SCI group. IMF (absolute and %) was related to the 90 or 120 min plasma glucose or plasma insulin (r 2 ¼ 0.71-0.40). Conclusions: IMF is a good predictor of plasma glucose during an OGTT and may be a contributing factor to the onset of impaired glucose tolerance and type II diabetes, especially in SCI. In addition, reports of skeletal muscle CSA should be corrected for IMF.

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N euromuscular electrical stimulation (NMES) is a promising tool in the rehabilitation of individuals with a limited ability to activate their skeletal muscles, 13,35,36 as well as a method of strength training and short-term resistance training in athletic populations. 26,27 During NMES application, the capacity to maintain performance is compromised compared to voluntary exercise, Experimental laboratory study.The primary purpose was to investigate the independent effects of current amplitude, pulse duration, and current frequency on muscle fatigue during neuromuscular electrical stimulation (NMES). A second purpose was to determine if the ratio of the evoked torque to the activated area could explain muscle fatigue.Parameters of NMES have been shown to differently affect the evoked torque and the activated area. The efficacy of NMES is limited by the rapid onset of muscle fatigue.Seven healthy participants underwent 4 NMES protocols that were randomly applied to the knee extensor muscle group. The NMES protocols were as follows: standard protocol (Std), defined as 100-Hz, 450-μs pulses and amplitude set to evoke 75% of maximal voluntary isometric torque (MVIT); short pulse duration protocol (SP), defined as 100-Hz, 150-μs pulses and amplitude set to evoke 75% of MVIT; low-frequency protocol (LF), defined as 25-Hz, 450-μs pulses and amplitude set to evoke 75% of MVIT; and low-amplitude protocol (LA), defined as 100-Hz, 450-μs pulses and amplitude set to evoke 45% of MVIT. The peak torque was measured at the start and at the end of the 4 protocols, and percent fatigue was calculated. The outcomes of the 4 NMES protocols on the initial peak torque and activated cross-sectional area were recalculated from a companion study to measure torque per active area.Decreasing frequency from 100 to 25 Hz decreased fatigue from 76% to 39%. Decreasing the amplitude and pulse duration resulted in no change of muscle fatigue. Torque per active area accounted for 57% of the variability in percent fatigue between Std and LF protocols.Altering the amplitude of the current and pulse duration does not appear to influence the percent fatigue in NMES. Lowering the stimulation frequency results in less fatigue, by possibly reducing the evoked torque relative to the activated muscle area.

The purposes of this study were to create a three-dimensional representation of strain during isometric contraction in vivo and to interpret it with respect to the muscle fiber direction. Diffusion tensor MRI was used to measure the muscle fiber direction of the tibialis anterior (TA) muscle of seven healthy volunteers. Spatial-tagging MRI was used to measure linear strains in six directions during separate 50% maximal isometric contractions of the TA. The strain tensor (E) was computed in the TA's deep and superficial compartments and compared with the respective diffusion tensors. Diagonalization of E revealed a planar strain pattern, with one nonzero negative strain (ε(N)) and one nonzero positive strain (ε(P)); both strains were larger in magnitude (P < 0.05) in the deep compartment [ε(N) = -40.4 ± 4.3%, ε(P) = 35.1 ± 3.5% (means ± SE)] than in the superficial compartment (ε(N) = -24.3 ± 3.9%, ε(P) = 6.3 ± 4.9%). The principal shortening direction deviated from the fiber direction by 24.0 ± 1.3° and 39.8 ± 6.1° in the deep and superficial compartments, respectively (P < 0.05, deep vs. superficial). The deviation of the shortening direction from the fiber direction was due primarily to the lower angle of elevation of the shortening direction over the axial plane than that of the fiber direction. It is concluded that three-dimensional analyses of strain interpreted with respect to the fiber architecture are necessary to characterize skeletal muscle contraction in vivo. The deviation of the principal shortening direction from the fiber direction may relate to intramuscle variations in fiber length and pennation angle.

Abducens nerve palsy is a common clinical finding in neurology practice. In many instances, the origin is obvious and management straightforward; however, the list of possible etiologies and mimics is vast and diverse and diagnostic decisions can be challenging and even controversial. This is especially true when the abducens nerve is affected in isolation, since in the current era of cost-effective medicine, it is critical to accurately diagnose etiologies that may lead to major morbidity or mortality with efficiency. Topics for highlighted updates in this review include management of isolated abducens nerve palsy with a high likelihood of a microvascular ischemic etiology; common imaging pitfalls and current state-of-the-art neuroimaging; and abducens palsy mimics.