Table 3 Positive and negative predictive values for having a large syrinx (≥ 4 mm)

Unprovoked scratching ^Q2

- Yes/No

- Often-Always/ Sometimes-Never

0.71

0.77

0.75

0.63

Scratching neck or shoulder ^Q3

0.74

0.69

Unilateral scratching ^Q4 in dogs scratching the neck or shoulder

0.72

-

Bilateral scratching ^Q4 in dogs scratching the neck or shoulder

0.80

-

Phantom scratching ^Q5

0.74

0.58

Aggravation of scratching during emotional arousal ^Q6

0.74

0.59

Aversion to touch on head, neck or shoulder ^Q7

0.74

0.58

A preferred head posture during sleep ^Q13

0.82

0.52