The natural course of sleep complaints in seniors - a longitudinal study

FICHTEN CS, CRETI L, WEINSTEIN N, TAGALAKIS V, AMSEL R, BRENDER W, LIBMAN E

Institute of Community and Family Psychiatry, Sir Mortimer B. Davis - Jewish General Hospital, 4333 Cote Ste Catherine Rd., Montreal, Quebec, Canada, H3T IE4.

What happens to older individuals who start out being good sleepers, poor sleepers, or somewhere in between, as they age? Although cross­sectional studies typically show a strong relationship between an immutable factor ­ age ­ and poor sleep, there are some indications that age alone is not necessarily associated with insomnia [1]. Therefore, it is also important to answer the question, "Which older individuals are likely to experience deterioration or improvement in their sleep?" Prospective, longitudinal data often provide insights about problem domains that cannot be obtained using cross­sectional methodologies. Therefore, our objective was to examine developmental trends longitudinally in order to explore the natural course of sleep problems in people over the age of 55 by conducting a 2 year follow­up of participants in our sleep and aging project.

Method

The 193 subjects were participating in a larger study [2]. They were community dwelling volunteers who completed a variety of measures at two testing times, approximately 2 years apart (M = 27 mo.). Mean age at Pre Test was 70. The sex ratio was approximately 1/3 male, and 2/3 female. According to our experimental criteria [2], 60 were Good Sleepers, 36 "Medium Quality," and 97 Poor Sleepers. Poor Sleepers had experienced insomnia for a mean of 14 years (range = 1 to 60). 43 participants who complained of insomnia were administered a 2 week analog treatment [3] shortly after the Pre Test battery, which included: Sleep Questionnaire, Pre­Sleep Arousal Scale, Brief Symptom Inventory (BSI), Eysenck Personality Inventory (EPI), Satisfaction With Life Scale, and Activities Questionnaire. At Post Test, subjects completed the Sleep Questionnaire and Life Events Scale.

Results

Change in sleep status with time. Table 1 shows that there was relatively little change with time: the majority of individuals who experienced Good or Poor Sleep at Pre Testing continued in these categories. Of those who changed, most changed only 1 category ­ to "Medium Quality" status. Table 2 shows that although most people (60%) remained Unchanged, there was both substantial Deterioration (24% of those who were not Poor Sleepers at Pre Testing deteriorated) as well as Improvement (41% of those who were not already Good Sleepers at Pre Testing improved). Results also highlight the different Improvement rates for the 43 subjects who received our analog treatment intervention (Treated) and the 90 Untreated Medium Quality and Poor Sleepers.

Predicting improvement in sleep status with time. ANOVA comparisons [2 Change (Unchanged/Improved) x 2 Treatment (Treated/Untreated)] were made on Pre Test scores of Unchanged and Improved subjects who were Medium Quality or Poor Sleepers at Pre Test. Dependent variables were: age, follow­up duration, sleep efficiency, sleep distress, daytime fatigue, adverse life events, diversity of daily activities, depression, satisfaction with life, pre­sleep cognitive arousal, and neuroticism. Results show only two significant Change main effects: those who Improved had lower Neuroticism (EPI) and Depression (BSI) scores than those who remained Unchanged. A discriminant function analysis based on 5 of the 11 predictor variables shows a 65.5% success rate, with 63% of the Unchanged group and 70% of the Improved group correctly classified (see Table 3).

Predicting deterioration in sleep status with time. Neither a series of ANOVA comparisons [2 Change (Unchanged / Deteriorated)] nor the discriminant function analysis revealed any significant findings (p .05); thus none of the demographic, sleep, or cognitive/affective variables could predict deterioration in our sample.

Table 1: Sleep Status at Pre & Post						Table 2: Improvement and Deterioration						Table 3: Variables Predicting Improvement
Sleep Status	Post Test					Change Pre to Post	Actual/Potential		% of Whole Sample			Variable	r
Pre Test	Good	Medium	Poor				# of Subjects	%				Lower Neuroticism	0.58
						Deteriorated (from Good or Medium)	23/96	(24%)	12%			Lower Cognitive Pre-Sleep Arousal	0.37
Good (n=60)	43	14	3			Unchanged (from Good, Med., or Poor)	116/193	(60%)	60%			Fewer Adverse Life Events	0.36
Medium (n=36)	17	13	6			Improved (from Medium or Poor)	54/133	(41%)	28%			Greater Diversity of Daily Activities	0.23
Poor (n=97)	9	28	60			Treated	26/43	(80%)				Lower Depression	0.22
						Untreated	28/90	(31%)				Younger	0.13
												Lower Sleep Distress Level	0.10

Discussion and Conclusions

The findings indicate that during a 2 year period, most individuals remained unchanged. Of those who were not already Good Sleepers, between 30% and 60% improved. Of those who did not already begin as Poor Sleepers, only 24% deteriorated. Our findings, like those of others who conducted longitudinal investigations [1], show that sleep disorder does not develop as a consequence of increasing age alone. Moreover, our findings indicate that improvement occurs relatively frequently.

People who improved were characterized by better psychological adjustment and lower levels of cognitive arousal during the presleep period. Those who deteriorated, on the other hand, could not be identified using the variables examined in this study. The findings suggest that targeting negative thinking and cognitive arousal in individuals with poor sleep may help facilitate improvement.

Findings reported elsewhere [3] show that a substantial number of older people are minimally distressed even by fairly severe sleep disruption [2]. Important goals for research include not only improvement of poor quality sleep but also identification of factors related to maintenance of good quality sleep in older people and the reduction of distress related to the experience of impaired sleep.

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[1] Foley, D.J., Monjan, A.A., Brown, S.L., Simonsick, E.M., Wallace, R. B., & Blazer, D.G. (1995). Sleep complaints among elderly persons: An epidemiological study of three communities. Sleep, 18(6), 425­432.

[2] Fichten, C.S., Creti, L., Amsel, R., Brender, W., Weinstein, N., & Libman, E. (1995). Poor sleepers who do not complain of insomnia: Myths and realities about psychological and lifestyle characteristics of older good and poor sleepers. Journal of Behavioral Medicine, 18(2), 189­223.

[3] Creti, L., Libman, E., & Fichten, C.S. (1994). A non­pharmacological treatment of insomnia in older individuals: Cognitive refocusing. Proceedings: 8th Annual Meeting of the Association of Professional Sleep Societies, (p. 106, #206).

Research supported by the Conseil québécois de la recherche sociale and NHRDP (Health Canada).