Table 2 Sensitivity and specificity of a positive response to individual QSVHI questions

QSVHI question	PD vs non-PD				PD vs PSP
QSVHI question	Sens	Spec	PPV	NPV	Sens	Spec	PPV	NPV
A Screening question	36	100	100	38	36	100	100	23
1 Presence	45	89	91	38	45	91	96	24
2 Passage	50	98	98	43	50	95	98	26
3 Illusions	45	91	93	39	45	95	98	24
B Total	72	89	94	55	72	86	97	37
1 Formed VH	36	93	93	36	36	100	100	23
2 VH, associated AH	8	100	100	29	8	100	100	17
Total VH	74	91	96	57	75	86	97	39
Total de novo VH	62	91	95	48	62	95	99	32

AH, auditory hallucinations; NPV, negative predictive value; PD, Parkinson’s disease; PPV, positive predictive value; QSVHI, Queen Square Visual Hallucination Inventory; Sens, sensitivity; Spec, specificity; VH, visual hallucinations.