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Table 2 Description of Sensory/Motor Tests for Carpal Tunnel Syndrome diagnosis (sorted alphabetically)

From: Diagnostic accuracy of sensory and motor tests for the diagnosis of carpal tunnel syndrome: a systematic review

Diagnostic Test Method Positive Result Threshold
Functional dexterity test [10] • Was administered independently on both sides. The task was to overturn all the pegs using only the movement of the first three fingers of a hand (without supinating or pronating the forearm or resting the elbow) starting from the top and the opposite side from the hand with which the test is performed. At the next time taken to complete the test, 5 s of penalties were added each time the patient pronated the forearm or touched the edge of the hole with the peg, and 10 s of penalty if the patient dropped the peg [10]. • If the total time is greater than the value corresponding to the 97th percentile of the normative data of the healthy Italian population, corrected by sex and age class [10].
Graphesthesia [20] • A figure was written on the finger pad with a blunt pencil [20] • The threshold was defined as the height in mm of the smallest figure that was identified by the patient [20].
Hand grip strength [22, 29] • Measured using a Jamar Hydraulic Hand Dynamometer (J.A. Preston Corporation, Jackson, Michigan) [22]
• Measured using either the Jamar dynamometer (Preston, Jackson, MI) or the Greenleaf Solo System (Palo Alto, CA). Grip was measured at each setting (I to V). Key (side-to-side) pinch, 3-jaw (tripod) pinch, and tip-to-tip pinch strengths were also measured using the Greenleaf Solo System. Each test was performed 3 times and the resultant mean values were used for data analysis [29].
• Hand grip and palmar pinch grip results were considered abnormal if they were more than 1.65 standard deviations below the mean for persons of the same age and sex [22].
• Evaluated grip strength by comparing subjects’ right hands with their left hands. They considered strength diminished if grip strength at position III on the dynamometer was more than 12% less on the affected side than the contralateral side. The same assumptions were applied to key pinch, 3-jaw (tripod) pinch, and tip-to-tip pinch strengths [29].
Hypoesthesia [20, 24, 28] • The sensibility screening was carried out with cotton wool, pins and warm and cold metallic rollers (40 °C and 20 °C, respectively) [20].
• A pinwheel was rolled across the palmar aspect of the index and small fingers [24].
• The sensitivity was evaluated by perception of pinprick [28]
• The test was considered positive if the subject reported hypesthesia of the index finger compared with the small finger [24].
Pinch grip strength [22, 26] • Measured with a B&L Pinch Gauge (B&L Engineering, Santa Fe Springs, California) [22]
• The pinch was performed by having the patient actively pinch a piece of paper between the tips of the thumb, index and long fingers using MP flexion and IP extension [26].
• Hand grip and palmar pinch grip results were considered abnormal if they were more than 1.65 standard deviations below the mean for persons of the same age and sex [22].
• If symptoms reproduced within 60 s [26].
Semmes-Weinstein monofilament testing (SWMFs) [6, 8, 21, 25,26,27, 29] • The 20-piece kit of SWMFs (North Coast Medical, San Jose, CA) was used to test sensory thresholds of the tips of the thumb, the index finger, and the long and small fingers using standard clinical techniques. Monofilaments were applied three times, with a positive response in one or more of the applications indicating that the stimulus was perceived [25].
• SMWs was done on the distal palmer pad of each digit of the hand in with enough force to bow the monofilament for a total of 1.5 s. The monofilaments were applied three times, with a positive response to one or more of the applications indicating that the stimulus was perceived [27].
• The monofilament was applied 3 times to each digit and the palm; a patient’s affirmative response to 1 or more of the monofilament applications indicated the stimulus was perceived. The monofilament kit contains 5 monofilaments to mark 5 selected thresholds: 2.83 (normal), 3.61 (diminished light touch), 4.31 (diminished protective sensation), 4.56 (loss of protective sensation), and 6.65 (loss of deep pressure sensation). The numeric value represents the logarithm of 10 times the force in milligrams required to bow the monofilament. All subjects were tested with their wrists in neutral position. The tests were then repeated after the subjects held their wrists flexed (Phalen’s maneuver) for 5 min [29].
• Recorded thresholds were categorized as normal or abnormal using four decision rules and two criterion measures. The decision rules were (1) a threshold higher than 2.83, (2) a threshold higher than 2.83 and higher than the threshold of the small finger (D5), (3) a threshold higher than 3.22, and (4) a threshold higher than 3.22 and higher than the threshold of the small finger. The two criterion measures were (1) the highest threshold of the three radial digits (D1-D3) and (2) the threshold of the long finger alone (D3) [25].
• A classification of abnormal was assigned if the SWMF threshold for any of the radial three digits was greater than 2.83 and greater than the threshold for the small finger [6, 26].
• Two separate sets of criteria:
• SWM 1: a positive test was defined as stimulus perception by the patient in any one of the radial three digits at a threshold value of 2.83 or an absent stimulus perception.
• SWM 2: a positive test was defined by stimulus perception at threshold value of 2.83 or an absence of stimulus perception using only digit 3 and using digit 5 for internal comparison.
• The patient must have had a digit 3 SWM test of 2.83 and a digit 5 test of 2.83 [27].
Tactile thresholds [20] • Pulses consisted of half sinusoids of 100 Hz from a Bruel & Kjaer shaker and were applied perpendicularly to the skin of the finger pads via a 2 mm diameter blunt plastic probe. The amplitude of the stimulus pulse was increased or decreased in small increments [20]. • The lowest amplitude that was felt in at least three of four consecutive stimulations was taken as the “yes response”, and the lowest amplitude that was not felt in 3 of 4 stimulations as the “no response”. The threshold was defined as the average of these 2 values [20].
Thenar atrophy9,307 • Thenar atrophy was defined as concavity of the thenar muscle group along the plane parallel to the palm and was scored as either present or absent [7]. • No description
Thumb abduction weakness [24, 28, 30] • The subject placed the touch pads of the thumb and small finger together. The examiner then applied a strong posteriorly directed force at the thumb interphalangeal joint toward the metacarpophalangeal joint of the index finger while instructing the subject to give maximum effort to keep the touch pads together [24].
• The strength of the abductor pollicis ensuring that the thumb was parallel to the index finger and the movement was occurring at the metacarpal trapezial joint [28].
• The test was positive if any weakness was detected [24].
Two-point discrimination (2PD)20,21,267 • The gap was successively decreased between the 2 points of a pair of blunted dividers, applied perpendicularly to the pulp of the finger [20].
• Static 2PD Tested on the pulp of the index finger using the Disk-criminator [21].
• Moving (dynamic) 2PD with electrocardiogram calipers with tips set 4 mm apart. The index and fifth fingertips were stroked five times with either one or two caliper tips [23].
• Two-point discrimination was performed in order to determine sensory loss. The Dellon discriminator was used on the index and third-finger fingertips [7].
• The threshold was defined as the smallest gap in mm at which the patient could identify that there were 2 points [20].
• The normal being taken as less than 6 mm [21].
• Failure to identify correctly the number of points on two or more strokes was considered abnormal [23].
• Greater or equal to 6 mm was accepted as altered sensation [7].
Vibrometry [20,21,22, 26] • A 100 Hz sine wave was produced by an electromagnetic vibrator. The peak to peak vertical movement of the 13 mm diameter blunt stimulus probe was recorded continuously in microns by means of an accelerometer. The variable tissue damping of the vibration amplitude was thus excluded as a source of error [20].
• Tested by the application of a branch of a tuning fork (256 cycles per second) to the pulp of the index finger and comparing the perceived intensity to that in the little finger in the same hand [21].
• Determined in the 2nd finger of each hand with a Vibratron II (Physitemp, Clifton, New Jersey) using a standard psychophysical technique and published normal values based on age and height [22].
• Testing with the prong of a 256 cycle per second tuning fork was performed on the fingertip [26]
• The perception threshold was determined with the method of limits, i.e. as the average of appearance and disappearance thresholds when the stimulus was successively increased and decreased. Vibratory threshold was determined at least 3 times at each site and the mean was calculated [20].
• A vibratory threshold was considered abnormal if it was more than 1.65 standard deviations above the mean for persons of that age and height [22].
Von Frey hairs [20] • A series of 10 nylon filaments of different diameters and length with log arrhythmically spaced bend pressures from 0.02 to 10 g were applied perpendicularly to the pulp of the finger. Each filament was applied 10 times at irregular intervals (to avoid the error of rhythmical response). • The threshold was defined as the pressure which was felt closest to half of the 10 stimulations [20].
Warm and cold thresholds [20] • Determined according to Fruhstorfer et al. (1976) [20]. • No description