ABSTRACT
PURPOSE: To prove that the relationship between sensory latencies and amplitudes is useful in determining the severity of neuropathies. This is achieved by deriving a mathematical relationship between sensory distal latency and amplitude. Determine whether sensory amplitudes below predicted correlate with a worse pathology. PROCEDURES: Patients seen for Nerve Conduction Studies by the Department of Physical Medicine and Rehabilitation at Cooper University Hospital between 12/1/12 and 12/31/14 were invited to participate in a prospective database. The median, ulnar and sural sensory latencies and amplitudes were analyzed with both linear and power regression. Patients with amplitudes above and below the regression curve were compared for latency, amplitude and velocity of other nerves. Carpal Tunnel Patients were analyzed to determine whether Median sensory amplitude below predicted correlated with more severe disease. RESULTS: For the Median nerve, Power Regression Analysis showed a stronger correlation (R2=0.54) than linear regression (R2=0.34). Patients with Median sensory amplitude below the power correlation curve showed significantly longer ulnar sensory latency, and lower sensory amplitude than those above. Carpal Tunnel Syndrome patients with Median sensory amplitude well below predicted by the power relationship showed more advanced disease. For the ulnar and sural sensory nerve, the difference between power and linear regression was not significant. CONCLUSIONS: A power regression curve correlates sensory latency and amplitude better than linear regression. The latency amplitude relationship correlates with other parameters of nerve function and severity of Carpal Tunnel Syndrome. This implies that below predicted sensory amplitude may indicate worse disease, and could be a useful diagnostic tool.
Subject(s)
Carpal Tunnel Syndrome/physiopathology , Neural Conduction , Reaction Time , Sensory Receptor Cells/physiology , Adult , Aged , Aged, 80 and over , Carpal Tunnel Syndrome/diagnosis , Female , Humans , Male , Median Nerve/physiopathology , Middle Aged , Muscle, Skeletal/physiopathology , Ulnar Nerve/physiopathologyABSTRACT
PURPOSE: To determine whether Contraction Induced H Reflexes (CIHR) can accurately detect cervical radiculopathy. METHODS: Comparison of CIHR results with Needle Electromyography at academic outpatient Electromyography/Nerve Conduction laboratories. Participants were all patients over 18 with a needle electromyography diagnosis of cervical radiculopathy. Patients were tested for CIHR in at least two upper extremity muscles in electromyographically proven myotomes bilaterally. Patients were requested to perform a moderate contraction while stimulus was applied proximally (elbow or Erb's point). Outcome measures included H Reflex onset latency and side-to-side latency differences. These were compared against previously established normal values. RESULTS: Overall, 10 of 15 patients who met criteria for cervical radiculopathy showed CIHR abnormalities (sensitivity = 67%; 95% confidence interval, 43-91). Counting each side and level separately, CIHR identified 16/27 radiculopathies (sensitivity = 59.2%; 95% confidence interval, 40.6-77.8). Contraction Induced H Reflexes identified 1 possible radiculopathy not seen on electromyography (specificity = 98%; 95% confidence interval, 95-100). CONCLUSIONS: Contraction induced H Reflexes have a sensitivity and specificity for cervical radiculopathy similar to the resting Gastroc-Soleus H Reflex.
Subject(s)
Electromyography/methods , Radiculopathy/diagnosis , Adult , Aged , Humans , Middle Aged , Muscle Contraction , Radiculopathy/physiopathology , Reflex , Sensitivity and SpecificityABSTRACT
Establishing a specific diagnosis is important in the effective management of individuals who present with a complaint of low back pain. Electrodiagnostic studies are an integral part of the diagnostic evaluation when the history or physical examination suggests that neural structures may contribute as symptom generators. Lumbo-sacral radiculopathies, plexopathies, and peripheral nerve injuries are of primary concern when evaluating individuals with low back pain, and electrodiagnostic studies assist in identifying and quantifying neurophysiologic injuries and abnormalities using techniques. A thorough, thoughtful, and individualized electrodiagnostic study performed by qualified physicians as an extension of a detailed history and physical examination can be an important and useful component in the proper evaluation of individuals with low back pain.
