Reliability of the Soleus H-Reflex in Different Sitting Postures.

The Soleus (SOL) Hoffmann reflex (H-reflex) is commonly recorded in sitting position. However, the reliability of recording is unknown. We assessed the reliability of SOL H-reflex amplitude measurements across multiple traces and sessions during erect, slumped, and slouched sitting postures using the generalizability theory. Five traces of the SOL H-reflex maximum amplitude (Hmax) were recorded from 10 healthy participants during erect, slumped, and slouched sitting postures in two sessions. A decision study analysis was then conducted to calculate the reliability coefficients of the Hmax for five traces and two sessions and to mathematically calculate the coefficients for seven and ten traces, and one and three sessions in the three sitting postures. For five traces and two sessions, the results showed reliability coefficients between 0.970 and 0.971, 0.980 and 0.979, and equal to 0.943 for erect, slumped, and slouched sitting, respectively. Averaging five traces of the Hmax in a single recording session was sufficient to obtain acceptable reliability in the three sitting postures (reliability range, 0.892-0.988). It was concluded that the SOL Hmax can be recorded during erect, slumped, and slouched sitting postures with adequate reliability.

Electrodiagnosis-based management of patients with radiculopathy: The concept and application involving a patient with a large lumbosacral disc herniation.

OBJECTIVES: The evaluation of patients with lower back pain (LBP) is based mainly on clinical examinations and imaging procedures that are subjective or anatomic in nature. The treatments, either physical therapy or osteopathy, lack evidence-based protocol and may be disruptive to the spine. Therefore, a neurophysiologic-based approach to managing such patients is necessary. METHODS: A 40-year-old female complained of LBP and radiculopathy for more than 12 years, a condition that was accompanied by numbness, tingling and weakness in the left leg. This study examined the effectiveness of using an innovative concept and method on a patient with a 19-mm disc herniation. An electro diagnosis-based evaluation and treatment approach testing tool, Soleus H-reflexes, was applied during unloading (with the patient lying down), loading (with the patient standing or sitting), and various trunk position protocols. A structured treatment was based on the results of H-reflex, including direction-sensitive exercises and manipulation, progressing from unloading to full loading. A custom-based home program was developed for sleeping and sitting positions, with all being directed at non-invasively decompressing the compromised nerve root. Data was analyzed using descriptive statistics. INTERVENTION AND RESULTS: Stepwise application of the developed procedures resulted in complete resolution of the radicular and spinal symptoms, with a reduction in the size of the herniated disc from 19 mm to 4 mm and recovery of the H-amplitude by the end of the treatment. Functional recovery was also complete by the end of the program. A follow-up after 12 months showed maintained results. CONCLUSIONS: The discussed concept and method exhibited their effectiveness in this case study, and the results obtained are due to the consistency and maintenance of the neural decompression using a direction sensitive therapy protocol. SIGNIFICANCE: Direction sensitive exercise therapy based on H-reflex testing is effective in treating large herniated lumbar discs.

Electromyographic activity of quadriceps muscle during sit-to-stand in patients with unilateral knee osteoarthritis.

OBJECTIVE: The sit-to-stand (STS) is a simple test to evaluate the functional performance of the quadriceps muscle in patients with knee osteoarthritis (OA). The aim was to evaluate the electromyographic (EMG) activity of the ipsilateral quadriceps during STS task at different seat heights and feet positions in patients with severe unilateral OA. The EMG activity was recorded in a group of eight participants with unilateral OA during the performance of STS task in four conditions: (1) knee-height seat with feet together, (2) knee-height seat with feet askew (feet side by side and heel-to-toe), (3) low-height seat (25% lower than knee-height seat) with feet together, and (4) low-height seat with feet askew. RESULTS: There was a statistically significant difference among the four conditions in the EMG activity (p =0.004). Particularly, the EMG activity of the quadriceps was significantly higher when participants rose from the low height with their feet askew than when they rose from the knee height with their feet placed together (p =0.004) or askew (p =0.002). These results recommend considering initial feet position and seat height when evaluating the functional activity of the quadriceps in patients with unilateral OA using STS test.

Similarities and differences in cervical and thoracolumbar multisegmental motor responses and the combined use for testing spinal circuitries.

STUDY DESIGN: Experimental study. OBJECTIVE: To determine similarities and differences of C7 and T11-12 multisegmental motor responses (MMR) studies for the upper limbs (UL) and lower limbs (LL). SETTINGS: Neuroscience Lab, TWU (School of Physical Therapy, TX, USA). METHODS: C7 and T11-12 percutaneous electrical stimulations were applied while recording muscle action potentials from ULs and LLs. RESULTS: The procedure of cervical MMR (CMMR) was easier in application than thoracolumbar MMR (TMMR), requiring less current intensities but cause more "jolts" in the trapezius/shoulder complex, due to close proximity of the stimulation electrodes. CMMR evoked large amplitude motor responses in the millivolts range in (UL) muscles, but smaller amplitude signal in (LL) muscles (in microvolts). TMMR evoked large amplitude motor responses in both UL and LL (in millivolts). The MMR amplitude was generally larger in the UL as compared to the LL, in the distal limb muscles more than in the proximal limb muscles. CMMR and TMMR for the UL were comparable in amplitude, latencies and action potential shapes. Signal latencies were longer for distal limb muscles as compared to proximal limb muscles and were slightly longer for LL as compared to UL muscles. MMR signals were either biphasic or triphasic in shape. CONCLUSION: CMMR and TMMR have similarities and differences in the methods and recording signal that must be considered during its clinical applications. Comparing the signal of the UL muscles with CMMR and TMMR could be a useful test for the integrity of the ascending and descending spinal pathways in patients with spinal cord injuries and diseases.

Intersession reliability of thoracolumbar multisegmental motor responses.

STUDY DESIGN: Experimental design. Objective To determine test-retest reliability across sessions of the thoracolumbar multisegmental motor responses (MMR) in the upper and lower limbs of healthy subjects. Test-retest reliability of MMR has not been established or examined in previous studies. SETTINGS: Neuro Laboratory of the Texas Woman's University (School of Physical Therapy, Houston, TX, USA). METHODS: The MMR of 15 healthy subjects were tested over two sessions. T11-12 vertebral segments were electrically stimulated using surface electrodes. MMR signals of the upper and lower limbs were recorded, using surface electrodes, from the upper extremity muscles (abductor pollicis brevis, flexor carpi radialis, biceps brachii, triceps brachii), and from the lower extremity muscles (vastus medialis obliqus, medial hamstring, soleus, tibialis anterior). The peak-to-peak maximum amplitude and deflection latency were the dependent parameters. Data from the first session was compared with a second session (on a different day), using interclass correlation coefficient (ICC), to evaluate the reliability across sessions. In addition, data from the right limbs were compared with the left limbs. RESULTS: MMR of the right and left, upper and lower extremities were comparable between limbs in all subjects. Further, signals were highly correlated between days of testing (ICC = 0.58-0.99) and was not statistically different between the two sessions in the same subject. CONCLUSION: These results indicate that MMR studies could be useful for serial testing of patients with neurological disorders, such as spinal cord injuries and diseases.

Similarities and differences of the soleus and gastrocnemius H-reflexes during varied body postures, foot positions, and muscle function: multifactor designs for repeated measures.

BACKGROUND: Although the soleus (Sol), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles differ in function, composition, and innervations, it is a common practice is to investigate them as single H-reflex recording. The purpose of this study was to compare H-reflex recordings between these three sections of the triceps surae muscle group of healthy participants while lying and standing during three different ankle positions. METHODS: The Sol, MG and LG muscles' H-reflexes were recorded from ten participants during prone lying and standing with the ankle in neutral, maximum dorsiflexion, and maximum plantarflexion positions. Four traces were averaged for each combination of conditions. Three-way ANOVAs (posture X ankle position X muscle) with planned comparisons were used for statistical comparisons. RESULTS: Although the H-reflex in the three muscle sections differed in latency and amplitude, its dependency on posture and ankle position was similar. The H-reflex amplitudes and maximum H-reflex to M-response (H/M) ratios were significantly 1) lower during standing compared to lying with the ankle in neutral, 2) greater during standing with the ankle in plantarflexion compared to neutral, and 3) less with the ankle in dorsiflexion compared to neutral during lying and standing for all muscles (p ≤ .05). CONCLUSION: Varying demands are required for muscles activated during distinctly different postures and ankle movement tasks.

H-reflex amplitude asymmetry is an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy.

BACKGROUND: Based on our clinical experience, the H-reflex amplitude asymmetry might be an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy. However, no data to support this assumption are available. The purpose of this study was to review and report the electrophysiological changes in H-reflex amplitude and latency in patients with radiculopathy in order to determine if there is any evidence to support the assumption that H-reflex amplitude is an earlier sign of nerve root involvement than latency. RESULTS: Patients with radiculopathy showed significant amplitude asymmetry when compared with healthy controls. However, latency was not always significantly different between patients and healthy controls. These findings suggest nerve root axonal compromise that reduced reflex amplitude earlier than the latency parameter (demyelination) during the pathologic processes. CONCLUSION: Contrary to current clinical thought, H-reflex amplitude asymmetry is an earlier sign/parameter of nerve root involvement in patients with radiculopathy compared with latency.

Flexor carpi radialis H-reflex modulation during spinal loading and unloading with varied forearm postures.

Flexor carpi radialis (FCR) H-reflex is usually recorded with the patient in lying or sitting postures while the forearm is positioned in supination or pronation to detect C7 radiculopathy. Its amplitude is smaller during forearm supination compared with pronation for unclear reasons and its recordings during postural loading conditions (i.e., sitting or lying) have not been previously reported. The purpose of this study was to examine FCR H-reflex recordings during varied cervical spine loadings and forearm positions. The FCR maximum H-reflex amplitude was recorded from 15 healthy participants during lying, free-sitting and sitting-with-load while the forearm was positioned in either supination or pronation. Four traces were averaged for each combination of conditions. Two-way repeated-measure analysis of variances (2 x 3) was used to examine the statistical differences. The average FCR H-reflex amplitude was significantly greater during free-sitting and sitting-with-load compared with the lying body position. The average FCR H-reflex amplitude was significantly greater when the forearm was positioned in pronation compared with supination. The increase in FCR H-reflex amplitude (augmentation) during forearm pronation and sitting postures compared with supination and lying may have been the result of combined neural and mechanical effects. These results encourage FCR H-reflex recordings during sitting with the forearm in pronation.

Vastus medialis H-reflex reliability during standing.

Vastus medialis H-reflex is a valid measure to examine quadriceps muscle voluntary activation and inhibition after knee injury. Its reliability during repeated sessions has not been established. The purpose of this study was to establish the intrasession and intersession reliability of vastus medialis H-reflex amplitude recordings during standing with varied knee flexion angles (0, 30, 45, and 60 degrees). Electromyography unit was used to elicit and record the vastus medialis H-reflex from the right leg of five healthy subjects. The femoral nerve was stimulated using 0.5-millisecond pulses at 0.2 pps of H-maximum. Four recordings of the vastus medialis H-reflex amplitude were recorded in three trials for each knee flexion angle within each session for two consecutive days. Reliability was calculated using intraclass correlation coefficients (ICC). Intrasession reliability during standing with varied knee angles was high (ICC [2, 4] range from 0.76 to 0.98), and intersession reliability during standing with varied knee angles was moderate to high (ICC [2, 1] range from 0.51 to 0.84). Recording four traces of vastus medialis H-reflex amplitude per trial was reliable. Vastus medialis H-reflex amplitude recordings while standing during varied knee flexion are reliable within and between sessions.

Soleus and vastus medialis H-reflexes: similarities and differences while standing or lying during varied knee flexion angles.

The H-reflex may be a useful measure to examine the lower extremity muscles activation and inhibition following an injury. Recording the vastus medialis H-reflex amplitudes in healthy subjects while standing or lying during varied knee flexion angles may establish a reference for comparison for patients with ACL injury. Vastus medialis and soleus H-reflexes were recorded from 14 healthy subjects while lying and standing during 0, 30, 45, and 60 degrees knee flexion. EMG unit was used to electrically stimulate the tibial and femoral nerves (using 0.5 ms pulses at 0.2 pps of H-maximum amplitude) and to record four traces of the soleus and vastus medialis H-wave and one trace of the M-wave peak-to-peak amplitudes. Repeated measures three-way ANOVAs were calculated with the global alpha=0.05. Results showed that (1) the average soleus H-reflex amplitude was significantly less during standing than lying across all knee flexion conditions, (2) the average vastus medialis H-reflex amplitudes showed no measurable significant differences between neutral standing compared with lying, (3) the average vastus medialis H-reflex amplitudes were significantly greater during standing knee flexion conditions (30, 45, and 60 degrees ) than lying or neutral standing, and (4) there were no differences between soleus and vastus medialis H-reflex amplitudes during lying across all knee flexion conditions. Data from H/M ratio follow the same pattern of H-amplitude. Recording the vastus medialis H-reflex amplitude during standing and knee flexion may be a reflective of the knee function. It is more specific than the soleus H-reflex because it reflects the changes in the excitability of the quadriceps motoneurons acting directly around the knee joint.