Table I.

Neurophysiological, clinical and patient‐oriented values averaged across subjects†

	CTS cases (SD)	Normal value	Z
Neurophysiological assessment
Radial SNCV 1 digit‐wrist, m/s	53.7 (5.3)	≥ 41 m/s	0.36
Radial SNAP 1 digit‐wrist, μV	13.3 (5.5)	> 5 μV	−0.03
Median SNCV 1 digit‐wrist, m/s	38.0 (6.8)	≥ 42 m/s	−3.34
Median SNAP 1 digit‐wrist, μV	13.8 (9.2)	> 5 μV	−0.84
Median SNCV 3 digit‐wrist, m/s	42.7 (4.9)	≥ 44 m/s	−3.38
Median SNAP 3 digit‐wrist, μV	15.2 (5.1)	> 6 μV	−0.33
Median distal motor latency, msec	3.5 (1.2)	≤ 3.9 msec	0.71
Median CMAP wrist‐tenar, mV	10.1 (5.6)	> 3 mV	0.12
Clinical assessment
Hi‐Ob mean score	2.6 (0.8)
PAIN	64.3%
Phalen test	78.6%
Patient‐oriented evaluation
BCTQ symptom score	2.9 (1.1)
BCTQ hand function score	2.4 (1.2)

^†Normative values are indicated in the third column for neurophysiological parameters, while for clinical and patient‐oriented parameters, healthy subjects are characterized by 0 value, i.e. absence of symptoms. Average Z‐scores for neurophysiological parameters are reported in the last column (normative one‐tail value at 5% = 1.645). Parameters out of normative range indicated in bold. SNCV, sensory nerve conduction velocity; SNAP, sensory nerve action potential; CMAP, compound motion action potential; HiOb, historical‐objective scale; PAIN, pain scale; BCTQ, Boston Carpal Tunnel Questionnaire.