. Author manuscript; available in PMC: 2012 Oct 1.

Published in final edited form as: Am J Geriatr Psychiatry. 2011 Oct;19(10):859–870. doi: 10.1097/JGP.0b013e318202bf5b

Table 4.

Results of GEE multivariate analyses (the global model) describing the relationships between stimulus, environmental and personal attributes and the three measures of engagement

		Duration		Attention		Attitude
		Odds Ratio	Confidence interval	Odds ratio	Confidence interval	Odds ratio	Confidence interval
Stimulus attributes
Type of Stimulus	Control - ref^a	1.00		1.00		1.00
	Real human^a	78.87^***	53.14–117.06	14.56^***	10.20–20.79	16.62^***	11.57–23.86
	Identity^b	13.71^***	10.24–18.36	6.24^***	4.53–8.60	5.33^***	3.86–7.36
	Simulated social^c	9.39^***	7.18–12.27	3.93^***	2.95–5.23	4.61^***	3.45–6.16
	Task/work	7.12^***	5.41–9.37	3.77^***	2.76–5.14	2.27^***	1.70–3.02
	Reading	7.01^***	5.26–9.34	3.77^***	2.74–5.17	2.81^***	2.05–3.85
	Inanimate social	5.70^***	4.37–7.45	3.05^***	2.24–4.13	3.51^***	2.60–4.75
	Pet	5.57^***	3.98–7.80	3.97^***	2.73–5.78	6.63^***	4.35–10.12
	Manipulative	5.19^***	4.05–6.64	2.96^***	2.24–3.92	2.38^***	1.82–3.11
	Music^a	2.72^***	2.00–3.72	1.05	0.76–1.44	1.10	0.79–1.53
Environmental attributes
Introduction	Short - ref^a	1.00		1.00		1.00
	Long	1.13^**	1.05–1.21	1.10^**	1.02–1.18	1.12^**	1.03–1.21
Sound	None - ref^a	1.00		1.00		1.00
	Low	3.02^*	1.15–7.92	3.02^*	1.10–8.26	2.27	0.91–5.66
	Moderate	4.49^**	1.72–11.70	4.93^**	1.80–13.50	3.36^**	1.36–8.33
	High	3.24^*	1.20–8.75	3.55^*	1.27–9.96	2.50	0.96–6.47
Social	0 - ref^a	1.00		1.00		1.00
	1	1.23	0.95–1.6 1	1.27	0.97–1.65	1.32^*	1.02–1.71
	2	1.47^*	1.09–1.99	1.40^*	1.02–1.92	1.53^**	1.11–2.11
	3	1.55^**	1.13–2.13	1.56^**	1.12–2.17	1.52^*	1.08–2.15
	4–9	1.58^**	1.18–2.12	1.56^**	1.17–2.08	1.58^***	1.22–2.05
	10–24	1.53^**	1.18–1.98	1.58^***	1.20–2.07	1.62^***	1.24–2.12
	25+	1.24	0.78–2.00	1.27	0.79–2.03	1.03	0.67–1.58
Personal attributes
MMSE	<3 - ref^a	1.00		1.00		1.00
	3–10	1.83^***	1.31–2.54	1.96^***	1.40–2.74	1.67^**	1.18–2.36
	>=10	2.87^***	2.03–4.05	3.29^***	2.29–4.71	2.59^***	1.79–3.75
ADL	<=1.6 - ref^a	1.00		1.00		1.00
	1.6–2.9	1.88^***	1.38–2.55	2.05^***	1.49–2.80	1.95^***	1.42–2.68
	>2.9	1.67^**	1.21–2.29	1.88^***	1.37–2.58	1.78^***	1.30–2.43
Clarity of speech	Clear speech - ref^a	1.00		1.00		1.00
	Unclear speech	0.67^*	0.49–0.92	0.69^*	0.51–0.95	0.68^*	0.50–0.93
	No speech	0.24^***	0.17–0.34	0.25^***	0.18–0.35	0.30^***	0.21–0.44

Note: P-values are based on Wald statistics with 1 degree of freedom for individual categories, and with k-1 degrees of freedom for the overall test of a variable with k categories.

p ≤ .05;

^**

p ≤ .01;

^***

p ≤ .001

p<.05 for all comparisons with other stimuli (Tukey’s pairwise comparison test)

p<.05 for all comparisons with other stimuli, except for simulated social and pet stimuli with respect to attitude (Tukey’s pairwise comparison test)

p<.05 for comparisons with all other stimuli except reading for duration; for comparisons with manipulative and music stimuli for attention; and for comparisons with reading, task, manipulative and music stimuli for attitude (Tukey’s pairwise comparison test)

Note. The following were not candidates for the multivariate analysis since they were not significant (P<0.2) in the univariate model: age, race, education, count of past interest, vision, hearing (duration), no. of psychotropic medications (duration & attitude).

The following variables entered the backward elimination procedure and were excluded from the final model due to non-significance: gender, marital status, no. of diagnosis, hearing, lighting, no. of medications, no. of psychotropic medications (attention).

Note: Live human social stimuli included a real baby, and one-on-one socializing with a research assistant; simulated social stimuli included a life-like (“real”) baby doll, a robotic animal, and a respite video; inanimate social stimuli included a childish-looking baby doll and a plush animal.

ref^a - the category is the reference value