Fig. 4

Response category threshold curve showing disordered thresholds for item 6 (“How often did the following symptoms in your hand wake you up at night? –numbness or tingling”) in the CTS-6. The response options were 0= “Never”, 1= “Once”, 2= “2 or 3 times”, 3= “4 or 5 times”, 4=“More than 5 times”. Note in figure ‘Person location’