ased on <strong>the</strong> quality <strong>and</strong> consistency <strong>of</strong> supportingevidence. The following rating system is used:<strong>Practice</strong> st<strong>and</strong>ards: generally acceptedprinciples for patient management that reflects ahigh degree <strong>of</strong> clinical certainty.<strong>Practice</strong> guidelines: recommendations forpatient management that reflect moderate clinicalcertainty.<strong>Practice</strong> options: o<strong>the</strong>r strategies for patientmanagement for which <strong>the</strong> clinical utility isuncertain.920 AAEM <strong>Practice</strong> Topic MUSCLE & NERVE June 2002
Table 1. Comparison <strong>of</strong> pooled sensitivities <strong>and</strong> specificities <strong>of</strong> EDX techniques to diagnose CTS.TechniquePooledsensitivity*Pooledspecificity*ABMedian sensory <strong>and</strong> mixed nerve conduction: wrist <strong>and</strong> palm segmentcompared to forearm or digit segmentComparison <strong>of</strong> median <strong>and</strong> ulnar sensory conduction between wrist <strong>and</strong>ring finger0.85 †(0.83, 0.88)0.85(0.80, 0.90)C Median sensory <strong>and</strong> mixed nerve conduction between wrist <strong>and</strong> palm 0.74 †DComparison <strong>of</strong> median <strong>and</strong> ulnar mixed nerve conduction between wrist<strong>and</strong> palm(0.71, 0.76)0.71(0.65, 0.77)E Median motor nerve conduction between wrist <strong>and</strong> palm 0.69 †FComparison <strong>of</strong> median <strong>and</strong> radial sensory conduction between wrist <strong>and</strong>thumb(0.64, 0.74)0.65(0.60, 0.71)G Median sensory nerve conduction between wrist <strong>and</strong> digit 0.65 †(0.63, 0.67)H Median motor nerve distal latency 0.63 †(0.61, 0.65)I Median motor nerve terminal latency index 0.62 †JComparison <strong>of</strong> median motor nerve distal latency (second lumbrical) to <strong>the</strong>ulnar motor nerve distal latency (second interossei)(0.54, 0.70)0.56 ‡(0.46, 0.66)K Sympa<strong>the</strong>tic skin response 0.04(0.00, 0.08)0.98 †(0.94, 1.00)0.97(0.91, 0.99)0.97 †(0.95, 0.99)0.97(0.91, 0.99)0.98 †(0.93, 0.99)0.99(0.96, 1.00)0.98 †(0.97, 0.99)0.98 †(0.96, 0.99)0.94 †(0.87, 0.97)0.98 ‡(0.90, 1.00)0.52(0.44, 0.61)*For each EDX technique to summarize results across studies, sensitivities were pooled from individual studies by calculating a weighted average. Incalculating <strong>the</strong> weighted average, studies enrolling more patients received more weight than studies enrolling fewer patients. Specificities weresimilarly pooled by calculating <strong>the</strong> weighted average. The data in <strong>the</strong> paren<strong>the</strong>ses below <strong>the</strong> sensitivity <strong>and</strong> specificity values represent <strong>the</strong> lower <strong>and</strong>upper 95% confidence limits <strong>of</strong> <strong>the</strong> weighted average, respectively. Data analysis courtesy <strong>of</strong> Dr. Gary Gronseth. †There was heterogeneity betweensome <strong>of</strong> <strong>the</strong> studies (<strong>the</strong> 95% confidence intervals <strong>of</strong> <strong>the</strong> sensitivities <strong>and</strong> specificities do not overlap). This disparity may be related to differences incase definition <strong>of</strong> CTS, <strong>the</strong> use <strong>of</strong> different cut-points to define an abnormal value, <strong>and</strong> differences in <strong>the</strong> average severity <strong>of</strong> <strong>the</strong> CTS patients in <strong>the</strong>different studies. ‡Results based on a single study.RECOMMENDATIONS REGARDING EDX STUDIES TOCONFIRM A CLINICAL DIAGNOSIS OF CTSThe recommendations below are identical to thosemade <strong>and</strong> endorsed in 1993 by <strong>the</strong> AmericanAcademy <strong>of</strong> Neurology, 3 <strong>the</strong> American Academy<strong>of</strong> Physical Medicine <strong>and</strong> Rehabilitation, 4 <strong>and</strong> <strong>the</strong>American Association <strong>of</strong> ElectrodiagnosticMedicine 5 with <strong>the</strong> clarification <strong>of</strong>recommendation 1 <strong>and</strong> 2a <strong>and</strong> <strong>the</strong> addition <strong>of</strong> 2cbased on new evidence reviewed in <strong>the</strong> secondCTS <strong>Literature</strong> <strong>Review</strong>. 2In patients suspected <strong>of</strong> CTS, <strong>the</strong> following EDXstudies are recommended (See Table I forsensitivity <strong>and</strong> specificity <strong>of</strong> Techniques A–K):1. Perform a median sensory NCS across <strong>the</strong>wrist with a conduction distance <strong>of</strong> 13 cm to14 cm (Technique G). If <strong>the</strong> result isabnormal, comparison <strong>of</strong> <strong>the</strong> result <strong>of</strong> <strong>the</strong>median sensory NCS to <strong>the</strong> result <strong>of</strong> a sensoryNCS <strong>of</strong> one o<strong>the</strong>r adjacent sensory nerve in<strong>the</strong> symptomatic limb (St<strong>and</strong>ard).2. If <strong>the</strong> initial median sensory NCS across <strong>the</strong>wrist has a conduction distance greater than 8cm <strong>and</strong> <strong>the</strong> result is normal, one <strong>of</strong> <strong>the</strong>following additional studies is recommended:a. comparison <strong>of</strong> median sensory or mixednerve conduction across <strong>the</strong> wrist over ashort (7 cm to 8 cm) conduction distance(Technique C) with ulnar sensory nerveconduction across <strong>the</strong> wrist over <strong>the</strong> sameshort (7 cm to 8 cm) conduction distance(Technique D) (St<strong>and</strong>ard), orb. comparison <strong>of</strong> median sensory conductionacross <strong>the</strong> wrist with radial or ulnarsensory conduction across <strong>the</strong> wrist in <strong>the</strong>same limb (Techniques B <strong>and</strong> F)(St<strong>and</strong>ard), orc. comparison <strong>of</strong> median sensory or mixednerve conduction through <strong>the</strong> carpaltunnel to sensory or mixed NCSs <strong>of</strong>proximal (forearm) or distal (digit)AAEM <strong>Practice</strong> Topic MUSCLE & NERVE June 2002 921