OBJECTIVE EMG FATIGUE (SPECTRAL) INDEX DECREASES IN SUBMAXIMAL ISOINERTIAL BACK ENDURANCE TEST: EFFECT OF FUNCTIONAL RESTORATION
M. Kankaanpaa-1,2, S.Taimela-3, S-M. Kokko-1, O.Hanninen-2 and O.Airaksinen-1,.
(1-Kuopio University Hospital, 2-Kuopio University, Kuopio and 3-DBC International, Vantaa, Finland)
Purpose. To test if objective EMG fatigue index decreases in submaximal back endurance test would serve as a method to monitor the improved back muscle endurance capacity in functional restoration program.
Methods. 15 middle aged females (age 45.6±5.8y, height 163.1±5.3 cm and weight 71.1±10.5 kg; mean±SD) with chronic low back pain (CLBP) participated in the 10 week functional restoration program. Back pain intensity (100 mm VAS) and functional disability (Oswestry) were assessed. Subjects performed 90 sec submaximal dynamic upper trunk extensions (30 rep/min, movement amplitude 25°flexion ,5°extension) in a specially designed testing unit. Level of loading was assessed on the basis of upper body weight. Bilateral lumbar paraspinal (L5) EMG fatigue index decreases (%/min,MPFslope) were assessed. Tests were made before (PRE) and after (POST) the rehabilitation. Statistics included repeated measures ANCOVA, rehabilitation serving as repeated measures factor and delta Oswestry as covariate. Two-sided significance was p<0.05.
Results. Oswestry (OSW) and VAS decreased significantly during the functional restoration (P<0.05). EMG fatigue index decreases (MPFslope) in submaximal isoinertial endurance test indicated improved endurance capacity of lumbar paraspinal muscles after functional restoration program (PRE: left -21.2±13.0 %/min; right -23.5±12.3 %/min, POST: left -16.0±13.9 %/min; right -17.9±14.5 %min, P<0.05).
Conclusions. EMG fatigue index decrease (MPFslope) in submaximal repetitive back endurance test seem to serve as an objective method to monitor the improvement of back muscle endurance in functional restoration.
Electro-diagnosis of Thoracic outlet syndrome (TOS) and Cervical radiculopathy (CR) -Analysis of N9 component in SSEPs -
Nakanishi Ryoji (Kumamoto Kinoh Hospital, Kumamoto, Japan)
N9 component recorded from Erb's point in SSEPs has been used only for the check of peripheral nerve lesions. We noticed that the minute evaluation of the N9 waveform could be helpful for the objective diagnosis of Thoracic outlet syndrome (TOS) and Cervical radiculopathy (CR).
In TOS, the upward slope (P8-N9) by ulnar nerve stimulation became bent and irregular, and the inter-peak latency was elongated. In severe cases, either a notch or small peak was found on the slope. It was confirmed by operated cases that these changes were observed in neurological TOS.
In CR, the downward slope (N9-P10) by ulnar and/or median nerve stimulation became irregular, and the inter-peak latency was elongated. In severe cases, N9 amplitudes were reduced. These findings were observed independent of cervical myelopathy.
On the basis of these above-mentioned results, we developed an auto-analytic program by applying the secondary differential method to N9 component. The epitome will be demonstrated.