A semi-structured interview to assess visual hallucinations in older people.
OBJECTIVE
Visual hallucinations are under-reported by patients and are often undiscovered by health professionals. There is no gold standard available to assess hallucinations. Our objective was to develop a reliable, valid, semi-structured interview for identifying and assessing visual hallucinations in older people with eye disease and cognitive impairment.


METHODS
We piloted the North-East Visual Hallucinations Interview (NEVHI) in 80 older people with visual and/or cognitive impairment (patient group) and 34 older people without known risks of hallucinations (control group). The informants of 11 patients were interviewed separately. We established face validity, content validity, criterion validity, inter-rater agreement and the internal consistency of the NEVHI, and assessed the factor structure for questions evaluating emotions, cognitions, and behaviours associated with hallucinations.


RESULTS
Recurrent visual hallucinations were common in the patient group (68.8%) and absent in controls (0%). The criterion, face and content validities were good and the internal consistency of screening questions for hallucinations was high (Cronbach alpha: 0.71). The inter-rater agreements for simple and complex hallucinations were good (Kappa 0.72 and 0.83, respectively). Four factors associated with experiencing hallucinations (perceived control, pleasantness, distress and awareness) were identified and explained a total variance of 73%. Informants gave more 'don't know answers' than patients throughout the interview (p = 0.008), especially to questions evaluating cognitions and emotions associated with hallucinations (p = 0.02).


CONCLUSIONS
NEVHI is a comprehensive assessment tool, helpful to identify the presence of visual hallucinations and to quantify cognitions, emotions and behaviours associated with hallucinations.
Mosimann
Urs Peter
UP
Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK. u.p.mosimann@ncl.ac.uk
Collerton
Daniel
D
Dudley
Robert
R
Meyer
Thomas Daniel
TD
Graham
Gemma
G
Dean
Jennifer Louise
JL
Bearn
Daniel
D
Killen
Alison
A
Dickinson
Lucy
L
Clarke
Mike Patrick
MP
McKeith
Ian Grant
IG
D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D004522:Educational Status; D004644:Emotions; D005128:Eye Diseases / Q000523:psychology; D005260:Female; D015577:Geriatric Assessment; D006212:Hallucinations / Q000175:diagnosis* / Q000209:etiology / Q000523:psychology; D006801:Humans; D007389:Internal-External Control; D007406:Interview, Psychological; D020961:Lewy Body Disease / Q000523:psychology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011594:Psychometrics; D012008:Recurrence; D015203:Reproducibility of Results; D013997:Time Factors