Practice Parameter and Literature Review of the Usefulness of ...

Practice Parameter: Carpal Tunnel SyndromeTable 10. Median Motor Nerve F-Wave Studies in CTS.Author Kuntzer 140Year 1994Number of NormalHands (subjects)70 (70)*Normal Subject’s Age:Mean (range)43 (25 to 70)Number of CTS Hands(patients)100 (100)*CTS Subjects Age:Mean (range)51 (26 to 85)Stimulation SiteWristRecording SiteAPBMinimum HandTemperature32°CF-Wave Parameter Persistence Chronodispersion Minimal latencyMinimal ulnarmedianF-wavelatency differenceMean durationMean amplitudeMeanamplituderatio†Normal ± SD 92.8 ± 9.2% 1.42 ± 0.37 ms 27.6 ± 2.1 ms 0.59 ± 0.91 ms 10.67 ± 1.62 ms 0.297 ± 0.124 mV 2.97 ± 1.21Criteria for AbnormalValueMean – 2 SD Mean + 2 SD Formula + 2 SD‡ Mean + 2 SD Mean + 2 SD Mean + 2 SD Mean + 2 SDAbnormal Value 2.2 ms SD = 1.4 72.4 >14 ms >0.545 mV >5.39Specificity of AbnormalValue91% (actual) 80% (actual) 86% (actual) 90% (actual) 10% (actual) 10% (actual) 70% (actual)Sensitivity of AbnormalValue35% 69% 16% 48% 2% 2% 15%* For each reference subject, only 1 hand was tested; for each CTS patient, only the most symptomatic hand was tested.† Mean F-wave amplitude as a percentage of the median CMAP.‡ Formula: minimum F-wave latency (ms) equals 0.12 × height (cm) + 6.8.Specificity equals the percentage of reference subjects’ hands with normal results and was either “actual” based on analysis of the test data from the reference population or an “estimate” basedon the statistical distribution of test data from the reference population.Sensitivity equals the percentage of CTS patients’ hands with abnormal results calculated from the test data on the CTS population.CTS = Carpal Tunnel Syndrome SD = Standard Deviation APB = Abductor Pollicis Brevis CMAP = Compound Muscle Action PotentialS940 CTS Literature Review© 2002 American Association of Electrodiagnostic Medicine