Introduction
In Belgium, as in many developed countries, the geriatric population is constantly increasing. In 2005, 17.2% of the population was older than 65 years and 1.6% older than 85 years. Among them, respectively 8 and 42% were living in nursing home residence. During the next 10 years, the Belgian population above 85 is expected to grow from 180,000 to 285,000, for a total population that will exceed by a small amount 10 millions [1]. With regard to the statistics of nursing home residents, they were 120,000 in 2001 [2] and already 150,000 in 2004 [1], located in 1771 residences.
Nursing care in nursing home residents remains a challenge, in particular during the night when nursing staff is reduced. Repeated physical staff care interventions in order to monitor incontinence, bed egress or behaviour troubles can also result, through repeated awakenings of the residents, into increased sleep fragmentation, sleep disruption and poor quality sleep [3], [4]. These repeated interventions also require a lot of work performed mainly by the nursing staff [5], [6].
Assistive technology is likely to increase in nursing homes in the future and bed-exit alarms have been developed in order to prevent falls that occur mainly in resident's room [7], [8]. Even if only 3–10% of these falls produce serious injury [9], it results in an important negative impact on patient health, functional status and quality of life; and leads to increased health-care costs [10]. Despite the large offer of commercially devices to increase staff surveillance, few well-conducted studies focused on alarm-effectiveness alone in fall prevention and the evidence to support the use of these devices remains limited [8], [11], [12]. Some data however suggest that the performance of multiple sensors may exceed that of single sensors [11].
With this in mind, we have conducted a feasibility study using a new flat bed multi-sensor monitoring equipment (Heasys®, BF Engineering and Datatrak, Brussels, Belgium). Heasys® has been developed to detect the presence of subjects in bed as well as body movements, and allow also the measure of body temperature and urine saturation. The purpose of the present study was to assess whether Heasys® was efficient to detect bed egresses, and if the detection of movements by Heasys® effectively corresponds to body position changes and is influenced or not by other nocturnal events such as arousals and/or leg/foot movements. For this purpose, healthy volunteers but also patients from a general sleep laboratory population were recorded during sleep; these patients were chosen because arousals and/or leg/foot movements are increased in sleep disorders such as obstructive sleep apnea syndrome (OSA) or periodic leg movements during sleep (PLMS) that are common in older subjects [13]. As the reference test for assessing Heasys® data, we used the current standard for the study of sleep and diagnosis of sleep disorders, namely complete polysomnography (PSG) whose measurements made simultaneously can indicate sleep stages/wake periods, body position and leg muscle electromyogram [14].