Carpel Tunnel Syndrome - AANEM€¦ · Carpal Tunnel Syndrome: Techniques for Diagnosis Faren H. Williams, MD Moss Rehabilitation Associates Michael T. Andary, MD Associate Professor

AMERICAN ASSOCIATION OF NEUROMUSCULAR & ELECTRODIAGNOSTIC MEDICINE


2621 Superior Drive NWRochester, MN 55901

(507) 288-0100

[email protected]

CARPAL TUN

NEL SYNDRO

ME:

TECHNIQUES

FOR DIAGN

OSISAA

NEM

WO

RK

SHO

PFaren

H. Williams, MD

Michael T. An

dary, MD


Copyright © October 2001


Workshop handouts are prepared as background didactic material to complement a hands-on workshop session.

This workshop handout was originally prepared in October 1993 and revised in October 2001. The idea and opinions

in this publication are solely those of the author(s) and do not necessarily represent those of the AANEM.

Carpal Tunnel Syndrome:Techniques for Diagnosis

Faren H. Williams, MDMoss Rehabilitation Associates

Michael T. Andary, MDAssociate Professor

Michigan State University

INDRODUCTION

Carpal Tunnel Syndrome (CTS) is a clinical entity which may bemisdiagnosed if one relies on clinical symptoms alone. Addingelectrodiagnostic studies to the patient’s workup quantitates theextent to which there is actual slowing of the median nerve; andby doing sensory studies across shorter segments, one can dif-ferentiate between entrapment at the carpal ligament versus amore diffuse peripheral problem. When the median nerve isstimulated at the wrist and the sensory nerve action potential(SNAP) is recorded, the latency from stimulation to the SNAPonset or peak is delayed in CTS patients. The first reported ab-normalities in the median nerve across the carpal ligament, usingnerve conduction techniques, were in 1956.1 Numerous varia-tions and refinements of different techniques have occurredover the last 10 years, and this handout will describe some of themore sensitive of these.2,3

Over the last decade, there has been more emphasis on com-paring the median sensory response to that of the ulnar andradial responses, and to comparing the more distal portion ofthe median sensory response to that across the carpal liga-ment.4,5,6,7 The CTS practice parameters which were publishedby AAEM in December 1993 recommended that shorter seg-ments be studied when the more traditional sensory nervestudies were normal, as a focal abnormality may be maskedwhen stimulating over a longer distance.2 The improvements inelectrodiagnostic testing may help with determining the severityof disease8, but further studies are indicated to validate this state-ment.

The “standard techniques” such as absolute distal sensorylatency between wrist and digit, and the absolute distal motorlatency between wrist and thenar muscles continue to be very

useful in the diagnosis of CTS, and should be used in conjunc-tion with the “newer” techniques described in this handout.

The goal of this workshop is to demonstrate several techniquesor combinations of techniques that help increase the sensitivityover “standard” sensory distal latencies, recognizing that thereare other techniques described in the literature.3,4,5,9,10,11,12,13,14,15

These techniques include:

1. Median-ulnar mixed nerve latency difference to the mid-palm.

2. Median-radial sensory latency difference to the thumb.3. Median-ulnar sensory latency difference to the ring finger.4. Median mid-palmar sensory latency compared to wrist

latency5. Short segment sensory stimulation across the carpal tunnel

(inching).6. Robinson cumulative summary index (CSI)7. Median (to lumbrical) - ulnar (to interosseous) motor

latency difference (LILD) across the carpal tunnel8. Median-thenar to ulnar-thenar motor latency difference

(TTLD)

Many individuals with CTS have concomitant underlyingmedical problems, or may have other neurological findings.Therefore, these tests should not be used in isolation. Otherneurological problems such as polyneuropathy or radiculopathymay be contributing to the patient’s symptoms. Abnormalitieson these tests suggest some median nerve compression at thewrist, but do not arbitrarily exclude other diagnoses. The diag-nosis of CTS remains a clinical diagnosis, utilizing electrodiag-nostic evidence for support.16

Electrodiagnostic test sensitivities are more variable, dependingon the individual test and the reference population, as well as thetest parameters for a given laboratory standard. To increase thesensitivity and correctly identify those individuals who havedisease may result in more patients without disease being mis-labeled, a higher false positive rate. One way to minimize thisproblem is to use more than one test from the list above to helpdetermine if the results are truly “abnormal.” Finding two tech-niques that are abnormal would minimize the possibility of afalse positive. Dr. Robinson recently concluded that the CSIsummary index using combined data from tests 1, 2, and 3 onthe list above increases the accuracy and improves diagnosticclassification over use of single test results.17

Another problem with interpretation of electrodiagnostic data isthat clinicians and researchers have traditionally used a normalGaussian (bell shaped curved) to calculate the mean + 2 stan-dard deviations (SD) as the normal range. With nerve conduc-tion studies, many tests do not fit this Gaussian distribution.There is only one tail of the bell shaped curve which is applica-ble. The latencies which are too slow are meaningful, whilethose in the other tail which are too fast are not relevant to thediagnosis of CTS. Hence, electrodiagnostic data needs to betransformed to be more accurate.18 Since the data does notfollow a Gaussian curve, between 2.5% and 13% of the popu-lation could be misclassified as falsely positive.18 As one doesmore tests, the probability of finding a false positive result in-creases.18,19 Refer to Table 1.

In this workshop, the focus will be on latencies, rather than am-plitude, given the variability and problems with specificity usingamplitudes.3 In this paper, latencies are reported from the neg-ative peak for SNAPs and to the initial negative deflection forCMAPs. The distance between the G1(active) and G2 (refer-

ence) has not always been given in the literature cited, so the dif-ferent interelectrode distances need to be considered when in-terpreting the reference values.20 All wrists should be in neutralduring measurement and recording, with the ground electrodeon the dorsum of the hand or between stimulating and record-ing electrodes.

TECHNIQUES

Median-Ulnar Mixed Nerve Palm Latency Differencefrom Palm to Wrist - This technique is illustrated in Figure 1.

FIGURE 1 is an orthrodromic conduction study with the stim-ulation distally, and the recording proximally. Redmond andRivner found that no normal subjects had a latency differencegreater than 0.4 ms and recommended a latency difference of0.5 ms or greater be used to avoid a high false positive rate. SeeTABLE 2 for more statistics.

If too small a latency difference is used, one may be within thestatistical error of the test and risk having a higher false positive

2 Carpal Tunnel Syndrome: Techniques for Diagnosis AANEM Workshop

TABLE 1. PROBABILITY OF FALSE POSITIVE*

Test Number of Abnormal TestsDone ≥1(%) ≥2(%) ≥3(%) ≥4(%)

1 2.5 X X X

2 4.9 0.1 X X

3 7.3 0.2 <0.1 X

4 9.6 0.4 <0.1 <0.1

5 11.9 0.6 <0.1 <0.1

6 14.0 0.9 <0.1 <0.1

10 22.4 2.5 0.2 <0.1

Assumptions: (a) 2.5% false positive using mean ±2 SD abnormalfor each test and (b) each parameter independent (this is not truewith CTS studies).

*Reprinted with permission (Robinson18)

Figure 1 Median-ulnar mixed nerve palm latency differencefrom palm to wrist: (a) stimulation is in the palm over themedian or ulnar nerve, 8 cm distal to the active recordingelectrode, and (b) recording is with a bar electrode at thewrist over the course of the median and ulnar nerves, respec-tively.

rate. It should be noted that the amplitude of the ulnar responseis much smaller than the median response,21 except when thereis median axonal loss or conduction block.22 At times, it may benecessary to rotate the anode around the cathode to get an ulnarresponse with a good takeoff and amplitude, and limit stimulusartifact. Some have recommended that the median stimulationbe between the 3rd and 4th metacarpal instead of the 2nd and3rd metacarpal, but in the authors’ experience there is no signif-icant advantage to doing that. Besides, one may get misleadingresults if the patient has a ring finger, which is entirely inner-vated by the ulnar nerve.21,23

Median-Radial Sensory Latency Difference to the Thumb- When using this technique, it is very important that one measure for thestimulating electrode with the thumb extended, as in Figure 2.

When stimulating the median nerve, one needs to measure fromG1 to the distal wrist crease and then bend to follow the courseof the median nerve. For the radial nerve, measure from G1and follow the course of the nerve. This test will be unreliableand yield erroneous results if the simultaneous stimulations ofthe median and radial nerves are done at different distances.Meticulous measurement is imperative if this method is used.The literature comments on a “Bactrian sign” (a doublehumped camel) if there are two peaks.5 When that occurs, thesecond peak is usually a delayed median response. However, it

may be possible to see a Bactrian sign in asymptomatic normalsubjects. It may also reflect a technical error if the stimulationof the median and radial nerves are at different distances as inFigure 3.

The amplitude of the radial response recording from the thumbis usually much smaller than the median nerve response. Ten(10) uv or less for the radial nerve response may be normal. Thesuperficial radial nerve may be more spared in a peripheral neu-ropathy; therefore, it may not help one differentiate between acarpal tunnel versus a peripheral neuropathy if the medial nerveis slowed in comparison. Studying the ulnar nerve, which isusually affected in a peripheral neuropathy will help to deter-mine if the slowing is truly carpal tunnel versus peripheral neu-ropathy.

It should be noted that in Cifu and Saleem’s study24, they usedsomewhat different techniques than those described in thishandout. They used a 3 cm bar electrode with the active record-ing electrode at the metacarpal phalangeal joint for the superfi-cial radial and a 3-cm bar electrode with the active recordingelectrode at the proximal interphalangeal joint of the middlefinger to determine the median sensory latency.

AANEM Workshop Carpal Tunnel Syndrome: Techniques for Diagnosis 3

TABLE 2. NORMAL VALUESMEDIAN-ULNAR PEAK DIFFERENCE, MIXED NERVE,PALM TO WRIST

Author’sAbnormal

Author Mean ± SD Value Comments

Kim 1983 0.05±0.12 ≥0.4 9 cm

Mills 1985 -0.03±0.16 ≥0.3 8.5-11 cm

Stevens 1987 ≥0.2 8 cm

Redmond 1988 0.05±0.14 ≥0.5 8 cm

(right hand) suggested

-0.02±0.12 range to avoid

(left hand) false positives

Jackson 1989 0.10±0.11 ≥0.31 8 cm

Andary 1996 0.0±0.14 ≥0.4 8 cm

Robinson 1998 0.69±0.47 ≥0.4 8 cm

(right palm)

0.57±9.54

(left palm)

Buschbacher 1999 ≥0.50 8 cm Figure 2 Median radial sensory latency difference to thethumb: (a) stimulation is over the median and radial nerves atthe wrist, 10 cm proximal to ring electrodes, and (b) recordingis with ring electrodes on the thumb.

Median-Ulnar Sensory Latency Difference to the RingFinger

This technique is easy to do because one can stimulate bothnerves without moving the recording electrode, similar to thethumb, median-radial technique.25 Sometimes, it is difficult toisolate the sensory response from the motor using this tech-nique. It is helpful to separate the fingers and move the record-ing electrodes further away from the palm to decrease anyartifact. If one is not directly over the median or ulnar nerveswith stimulation, or if the stimulation intensity is too high, thenthere may be volume conduction of the median to the ulnarnerve and vice versa. One needs to scrutinize the waveforms tobe sure that there is a distinct median vs. ulnar response. If themedian response is delayed and both nerves are stimulated, adouble hump (Bactrian sign) can be seen.6

Since this is an antidromic procedure, the amplitudes may belarger than orthodromic. Another potential problem is that thepatient may have an entirely median or entirely ulnar innervatedring finger. If that is the case, the results will be misleading. Itis helpful to observe different amplitudes and/or latencies toclarify a median from ulnar response.


Figure 3 Intermediate stimulation can cause shorter dis-tance from depolarization for the radial nerve with a 2-3 cmdifference. This could increase the median-radial difference by0.4 to 0.6 ms giving a double hump in normal subjects.

Figure 4 Median-ulnar sensory latency difference to the ringfinger: (a) stimulation is 14 cm proximal to the G1 ring elec-trode, over the median or ulnar nerves at wrist, and (b)recording is with ring electrodes on the ring finger.

TABLE 4. NORMAL VALUESMEDIAN-ULNAR DIFFERENCE TO RING FINGER

Author’sAbnormal Abnormal

Latency Mean ± SD Value Comments

Johnson 1981 0.125±0.11 >0.34 14 cm

antidromic

Monga 1982 -0.01±0.15 ≥0.4 14 cm

orthodomic

Jackson 1989 0.09±0.13 >0.35 14 cm

antidromic

Uncini 1989 0.14±0.11 >0.5 average 13 cm

orthodromic

Charles 1990 0.06±0.26 ≥0.5

Robinson 1998 1.04±0.90 ≥0.4

(right hand)

0.91±0.81

(left hand)

Median-Median Mid-palmar Sensory Study

The median nerve is studied antidromically, with recording elec-trodes over the index finger, and stimulation sites at the tradi-tional 14 centimeters, and midway on the palm at 7 centimeters(Figure 5).7,9,13,14,15

The advantage of this technique is that one can stimulate acrossshorter distances, with the proximal one being across the carpalligament which is where the median nerve is compressed incarpal tunnel, hence increasing the possibility of detecting amore focal lesion. At the same time, one can compare thisresult with the more distal short segment. If the latter is slowed,but more prolonged than the proximal segment, it suggests a pe-ripheral neuropathy rather than a carpal tunnel. If both seg-ments are fairly similar in latencies, then there is no focalslowing.

Median-Sensory Short Segment Stimulation

One way to more accurately identify slowing or the focal site ofnerve compression is to stimulate across the carpal ligament,looking for evidence of conduction block. The median nerve isstimulated every 1 centimeter from the proximal wrist creasedistally to the mid-palm. With carpal tunnel, there may belatency differences and amplitude changes, with the amplitudedistal to the conduction block being larger. Nathan reported


TABLE 3. NORMAL VALUES SENSORY PEAK MEDIAN-RADIAL DIFFERENCES TO THUMB

Author’sAbnormal

Author Mean ± SD Value Comments

Carroll 1987 0.09±0.10 >0.3 (age 16-39) (6.7 to 10.5 cm)

orthodromic

0.15±0.12 >0.4 (age 40-59)

0.13±0.08 >0.3 (age 60-82)

Johnson 1987 .015 ≥0.5 10 cm

antidromic

Cassvan 1988 >0.4 Bactrian sign 11 cm

present was abnormal antidromic

Jackson 1989 0.13±0.12 ≥0.38 10 cm

antidromic

Andray 1996 0.06±0.11 ≥0.4 10 cm

antidromic

Robinson 1998 1.06±0.60 0.5

(right hand)

0.92±0.64

(left hand)

Figure 5 Technique for antidromic median sensory stimula-tion at 7 and 14 cm.

that the most frequent areas of slowing were 2 to 4 cm distal tothe wrist crease and there were no isolated areas of slowing 1 to2 cm proximal to the wrist crease.26 The authors, therefore, rec-ommend starting stimulation 1 cm proximal to the distal wristcrease. The largest latency difference over a 1 cm segment isrecorded to determine abnormality. This technique can localizethe focal entrapment, but may be of more academic interestthan clinical utility. Surgeons tend to do similar procedures forall carpal tunnel releases; and therefore, detecting a focal en-trapment site is not as critical as with ulnar neuropathies. Theauthors have seen recurrent CTS after surgery showing focaldelay in the distal carpal tunnel. See Figure 6.

Summary Index

Robinson looked at the a combined sensory index (CSI) bylooking at three latency differences: median-ulnar (8 cm) mid-palmar orthodromic (palmdiff); median-ulnar ring finger (14cm) antidromic (ringdiff); and median-radial thumb (10 cm) an-tidromic (thumbdiff). The sum of the three differences was theCSI. Using the index, the sensitivity for the test was 83.1%,

compared to 69.7%, 74.2%, and 75.8%, respectively for thetests listed above. Specificities also increased to 92.3%, 98.5%,and 100%, depending on whether 1, 2, or 3 tests were requiredto be abnormal. However, when all 3 tests were required to beabnormal, then the sensitivity dropped.17 This summary indexhelps to enhance the separation of healthy and diseased patients.

In order to use this index, one must do all 3 sensory tests oneach hand. CSI = palmdiff + ringdiff + thumbdiff. Referencevalues for each of the tests are listed in Table 7.

The CSI with a reference value of 0.9 msec was better than thesingle tests with a sensitivity of 83.1% and specificity of 95.4%.Both sensitivity and specificity remain very good when a CSI of_=_1.0 ms is used. This index helps to decrease the false posi-tive rate since when calling CTS based on only one abnormaltest, there are more false postives. The index is also usefulbecause the literature has failed to demonstrate the superiorityof any one test, nor is there evidence that any one of the mediannerves branches is more preferentially affected.17


Figure 6 Median-sensory short segment stimulation(inching): (a) stimulation starts 1 cm proximal to the distal wristcrease and continues segmentally in 1 cm increments to 6 cmdistal wrist crease for a total of 8 stimulations of the mediannerve, and (b) recording is with ring electrodes on the indexfinger or middle finger.

TABLE 5. NORMAL VALUESMEDIAN 14 CM AND 7 CM ANTIDROMIC SENSORYSTUDIES

Onset Latencies Peak LatenciesAuthor Mean ± SD Mean ± SD

Escobar 1.65±.15

1985 (palm)

Wongsam 1.58±0.15

1995 (palm)

3.07±0.2

Buschbacher 1.4±0.2 (7 cm) 2.0±0.4 (7 cm)

1999 2.7±0.3 (14 cm) 3.4±.03 (14 cm)

TABLE 6. NORMAL VALUESMEDIAN SENSORY SHORT SIGMENT STIMULATION(1 CM) LONGEST LATENCY DIFFERENCE

Author’sAbnormal


Kimura 1979 ≥0.5 ms index finger

Nathan 1988 0.29±0.08 ≥0.5 ms (97% Spedificity)

or middle finger

≥0.4 ms (81% Specificity)

More recent work by Robinson has shown that the CSI is morevaluable in helping to diagnose CTS when the palmdiff is 0-0.3ms; ringdiff 0.1-0.4 ms; and thumbdiff 0.2-0.7 ms. When thetests fall outside these ranges, then additional testing does notincrease the diagnostic yield significantly.27

Median-Lumbrical to Ulnar-Interossei LatencyDifference (LILD).

Preston9 reports obtainable responses in all their patients in eval-uating the median-ulnar motor latency difference to the intrin-sics. When measuring the initial deflection for the medianCMAP, there is often a SNAP visible, occasionally makinglatency determinations difficult. Since there are not as manycomparative studies using this technique, we caution against thepossibility of false positives. The authors have noticed latencydifferences up to 0.6 ms in patients not felt to have CTS.28,29 Theauthors believe that this test may improve the diagnostic yieldwhen the median-ulnar palmar comparison is normal or equiv-ocal, yet one must be careful not to diagnose carpal tunnel in thecontext of normal median sensory studies.


TABLE 7. REFERENCE VALUES FOR EACH OF THETESTS BASED ON MEAN + 2 SD OF THE OPTIMALLYTRANSFORMED DATA FROM NON-CTS SUBJECT

Palmdiff ≤0.3 ms

Ringdiff ≤0.4 ms

Thumbdiff ≤0.5 ms

CSI ≤0.9 ms

TABLE 8. SENSITIVITY, SPECIFICITY, POSITIVE PREDICTIVE VALUE, AND NEGATIVE PREDICITVE VALUE FOR EACH DI-AGNOSTIC TEST, FOR THE STRATEGY OF MAKING A DIAGNOSIS BASED ON ONE OF THREE, TWO OF THREE, ORTHREE OF THREE TESTS ABNORMAL, AND FOR THE COMBINED SENSORY INDEX AND DISCRIMINATE SENORYINDEX.

Sensitivity Specificity PPV NPV

Palmdiff 69.7% 96.9% 95.8% 76.8%

Ringdiff 74.2% 96.9% 96.2% 78.8%

Thumbdiff 75.8% 96.9% 96.2% 79.7%

One of three tests 84.8% 92.3% 91.8% 85.7%

Two of three tests 74.2% 98.5% 98.2% 78.0%

Three of three tests 56.1% 100% 100% 69.1%

CSI ≤ 0.9 83.1% 95.4% 94.8% 85.0%

CSI ≤ 1.1 81.8% 100% 100% 84.1%

Figure 7 Median-ulnar motor latency difference to intrinsics:(a) stimulation is at the wrist, with the same distance (usually 9to 10 cm) proximal to G1 along the course of the median andulnar nerves, and (b) recording is at G1 between the 2nd and3rd metacarpals in the distal third of metacarpals over the 2ndlumbrical and interossei and at G2 over the proximal interpha-langeal joint of the index finger.


This technique can be useful in severe cases of CTS where theSNAPs are absent and the recurrent median motor branch is se-verely injured as the axons to the lumbricals can be relativelyspared, even if the motor response to the APB is absent.30 Thisstudy can help to determine whether there is any remainingviable median nerve which may be spared with surgery.

Median-Thenar to Ulnar-Thenar Latency Difference(TTLD)

The median distal motor latency (DML) to the thenar muscleshas been a standard technique for many years. The G1 is placedover the thenar eminence, usually at the mid-point of the firstmetacarpal bone over the APB. G2 is placed over the thumb,usually over the IP joint. Stimulation is 1 cm. proximal to thedistal wrist crease on the median nerve. Occasionally the G1needs to be moved to obtain an initial negative deflection.

The ulnar nerve can be stimulated 1 cm proximal to the distalwrist crease and a CMAP recorded from the adductor pollicus,flexor pollicus brevis, and in patients with Riche-Canneu anas-tomoses, the opponens and abductor pollicus brevis also havesome ulnar innervation. The ulnar waveform usually has aninitial positive deflection and the latency should be taken fromthis point. The authors report an abnormal value of > 0.8msec.31 We caution the risk of false positives; and we have seenmedian-ulnar differences up to 1.4 msec. in patients who maynot have CTS. This may be related to difficulty with determin-ing the exact “take off” for the motor response.

REFERENCES

11. Simpson JA. Electrical signs in the diagnosis of carpal tunnel andrelated syndromes. J Neurol Neurosurg Psychiatry 1956;19:275-280.

12. American Association of Electrodiagnostic Medicine, AmericanAcademy of Neurology, and American Academy of PhysicalMedicine and Rehabilitation, Practice Parameter forElectrodiagnostic Studies in Carpal Tunnel Syndrome: SummaryStatement. Muscle Nerve. 1993;16:1390-1391.

13. American Association of Electrodiagnostic Medicine, QualityAssurance Committee. Jablecki CK, Andary MT, So YT, WilkinsDE, Williams FH. Literature review of the usefulness of nerve con-duction studies and electromyography for the evaluation of patientswith carpal tunnel syndrome. Muscle Nerve 1993;16:(12)1392-1414.

14. Andary MT, Frankhauser MJ, Ritson JL, Spiegel N, Hulce V, YosefM, Stanton DF.Comparison of sensory and mid-palm studies toother techniques in carpal tunnel syndrome. Electromyogr. Clin.Neurophysiol 1996;36:279-285.

15. Johnson EW, Sipski M, Lammertse T. Median and radial sensory la-tencies to digit I: normal values and usefulness in carpal tunnel syn-drome. Arch Phys Med Rehabil 1989;70:199-204.

16. Johnson EW, Kukla RD, Wongsam PE, Piedmont A. Sensory laten-cies to the ring finger: normal values and relation to carpal tunnelsyndrome. Arch Phys Med Rehabil 1981;62:206-208.

17. Wongsam PE, Johnson EW, Weinerman JD. Carpal tunnel syn-drome: use of palmar stimulation of sensory fibers. Arch Phys MedRehabil 1995;76:246-279.

Figure 8 Schematic of electrode placement for evoking themedian-thenar, ulnar-thenar, and ulnar-hypothnar compoundmuscle action potentials, and the median and ulnar F waves.

TABLE 9. NORMAL VALUESMEDIAN-ULNAR LATENCY DIFFERENCE TOINTRINSICS

Author’sAbnormal


Preston and

Logigian 1992 0.08±0.16 <0.4 Identical distance

of stimulation for

median and ulnar

Sheenan 1995 >0.04

TABLE 10. NORMAL VALUESMEDIAN-THENAR TO ULNAR-THENAR LATENCYDIFFERENCE (PTLD)

AbnormalLatency Value

Sander 0.8 ms

18. Aulisa L, Tamburrelli F, Padua R, Romanini E, Monaco ML, PaduaL. Carpal tunnel syndrome:indication for surgical treatment based onelectrophysiologic study. J Hand Surg 1998;23A:687-691.

19. Preston DC, Logigian EL. Lumbrical and interossei recording incarpal tunnel syndrome. Muscle Nerve 1992;15:1253-1257.

10. Jackson DA, Clifford JC. Electrodiagnosis of mild carpal tunnel syn-drome. Arch Phys Med Rehabil 1989:70(3):199-204.

11. Johnson EW. Practical electromyography, ed 2. Baltimore, Williams& Wilkins Publishers, 1988.

12. Rivner MH. Carpal tunnel syndrome: a critique of “newer” nerveconduction technques. In: 1991 AAEM Course D: Rochester, MN:American Association of Electrodiagnostic Medicine; 1991. pp. 19-24.

13. Buschbacher RM. Mixed nerve conduction studies of the medianand ulnar nerves. Am J Phys Med Rehabil 1999;78(6):S69-S74.

14. Escobar P, Goka RS. Carpal tunnel syndrome. Palmar sensory laten-cies to 3rd digit and wrist. Orthopaedic Review 1985;14:49-55.

15. Padua L, Monaco ML, Valent EM, PA Tonali. A useful electrophys-iologic parameter for diagnosis of carpal tunnel syndrome. MuscleNerve 1996;48-53.

16. Buch-Jaeger, Foucher G. Correlation of clinical signs with nerve con-duction tests in the diagnosis of CTS. J Hand Surg (Brit andEuropean Vol.) 1994;19B:6:720-724.

17. Robinson LR, Micklesen PB, Wang L: Strategies for analyzing nerveconduction data: Superiority of a summary index over single tests.Muscle Nerve 1998;21:1166-1171.

18. Robinson LR, Temkin NR, Fjuimoto WY, Stolov W. Effect of sta-tistical methodology on normal limits in nerve conduction studies.Muscle Nerve 1991;14:1084-1090.

19. Redmond MD, Rivner MH: False positive electrodiagnostic tests incarpal tunnel syndrome. Muscle Nerve 1988;11(5):511-518.

20. Cohn TG, Wertsch JJ, Pasupuleti DV, Loftsgaarden JD, Schenk VA:Nerve conduction studies: Orthodromic vs antidromic latencies.Arch Phys Med Rehabil 1990;71(8):579-582.

21. Kim LYS. Palmar digital nerve stimulation to diagnose carpal tunnelsyndrome. Orthop Rev 1983;12(6):59-63.

22. Kuntz T. Carpal tunnel syndrome in 100 patients: sensitivity, speci-ficity of multi-neurophysiological procedures and estimation ofaxonal loss of motor, sensory, and sympathetic median nerve fibers.J Neuro Sciences, 1994;127:221-229.

23. Stevens JC. AAEE minimonograph #26: The electrodiagnosis ofcarpal tunnel syndrome. Muscle Nerve 1987;10(2):99-113.

24. Cifu DX, Saleem S. Median radial latency difference: its use in screen-ing for carpal tunnel syndrome in twenty patients with demyelinatingperipheral neuropathy. Arch Phys Med Rehabil 1993;74:44-47.

25. Cioni R, Pamero S, Paradiso C, Glamnini F, Battistini N, RushworthG. Diagnostic specificity of sensory and motor nerve conductionvariables in early detection of carpal tunnel syndrome. J. Neurol1989;236:208-213.

26. Nathan PA, Srinivassan H, Doyle LS, Meadows KD. Location of im-paired sensory conduction of the median nerve at the carpal tunnelsyndrome. J Hand Surg 1990;15(1):89-92.

27. Robinson LR, Micklesen PJ, Wang L. Optimizing the number oftests for carpal tunnel syndrome. Muscle Nerve 2000;23:1880-1882.

28. Sheean GL, Houser MK, Murray NMF. Lumbrical-interosseouslatency comparison in the diagnosis of carpal tunnel syndrome.Electroencep Clin Neurophys 1995;97:285-289.

29. Uncini A, Di Muzio A, Awad J, Manente G, Tafuro M, D Gambi.Sensitivity of three median-to-ulnar comparative tests in diagnosis ofmild carpal tunnel syndrome. Muscle Nerve 1993;16:1366-1373.

30. Trojaborg W, Grewal RP, Weimer LH, Sheriff P. Value of latencymeasurements to the small palm muscles compared to other con-duction parameters in the carpal tunnel syndrome. Muscle Nerve1996;19:243-245.

31. Sander HW, Quinto C, Saadeh PB, Chokroverty S. Sensitivemedian-ulnar motor comparative techniques in carpal tunnel syn-drome. Muscle Nerve 1999;22:88-98.





(507) 288-0100

[email protected]

CARPAL TUN

NEL SYNDRO

ME:

TECHNIQUES

FOR DIAGN

OSISAA

NEM

WO

RK

SHO

P

Faren H. W

illiams, MD

Michael T. An

dary, MD

Documents

Carpel Tunnel Syndrome - AANEM€¦ · Carpal Tunnel Syndrome: Techniques for Diagnosis Faren H. Williams, MD Moss Rehabilitation Associates Michael T. Andary, MD Associate Professor