Alzheimer\'s Disease

We performed a retrospective study of the behavior of lost Dementia of Alzheimer\'s Type (DAT) patients who became the subjects of organized Search and Rescue efforts. We compared the DAT patients behavior to the behavior of elderly lost victims that possessed normal cognitive abilities. Data for both populations was from the Virginia Department of Emergency Services lost subject database. We found that normal elderly individuals on average traveled a greater straight line distance (2.56 km) from the Point Last Seen (PLS) than DAT patients (0.88 km). The median straight line distance from the PLS was the same for both populations (0.8 km). The mortality rate for DAT patients was 19 percent. Mortality was caused by hypothermia, dehydration, and drowning. No fatalities were found among DAT patients when they were located within 24 hours. A mortality rate of 46 percent was found for patients requiring more than 24 hours to locate. This 24 hour survivability window suggests that lost DAT patients require an immediate and aggressive search response.

Keywords: Wandering, Alzheimer\'s Disease, Lost person behavior, missing person, Behavioral profile


Our goals are to create a preliminary behavioral profile of lost Dementia of Alzheimer\'s Type (DAT) patients, determine factors that impact survivability, and to create a database. Incident commanders in missing person searches rely on lost person behavior profiles and statistics for the initial deployment of resources, development of objectives, and predicting survivability. The major textbooks and field guides currently used by incident commanders combine both Alzheimer\'s with Elderly subjects or fail to give any numbers [1,2]. Unfortunately, search subjects suffering from Alzheimer\'s disease are grouped with elderly subjects or undocumented.

Current estimates of Alzheimer\'s Disease are four million based upon an estimated 10.3% of the population over the age of 65 suffers from probable Alzheimer\'s disease [3]. An estimated 12-14 million Americans will be affected by the year 2040 [4]. The increase is believed to be due to an increase in awareness of the disease and an increase in the age of the U.S. population [5]. Regional demographics also will affect the percentage of Alzheimer\'s cases found in each state. Indeed there appears to be a higher prevalence in rural areas [6] and among those with less education [7,8]. It is this particular subset of DAT patients that often results in search and rescue incidents.

Alzheimer\'s disease (AD) is a disease of exclusion since only after the patients\' death can it be diagnosed positively. However, DAT [9] or probable AD is characterized well and can be documented with behavioral tests [10,11,12]. Wandering significantly increases with further deterioration of the DAT patient. Among mild cases of DAT, 18% of the patients wander, while in severe cases, wandering increases to 50% [13]. Other studies have made estimates of the prevalence of wanderers ranging from twelve to thirty-nine percent [14,15]. Another study reported twenty-six percent of AD patients getting lost in the outdoors in the preceding week [16].

Wanderers are distinguishable from non-wanderers by constant disorientation, inability to know when lost, better social skills, and are more active [17]. These traits have serious consequences when the patient wanders into a wilderness or rural location. Looking at several factors that affect survival in patients with DAT only the severity of DAT, behavioral problems, and wandering or falling correlate to decreased longevity [18]. One law enforcement agency reported four deaths out of 450 (1%) separate episodes of critical wandering [19]. Nova Scotia\'s Emergency Measures Organization reported a mortality rate of seven out of fifteen (47%) among "walk-a-ways" (Alzheimer\'s, other senile dementia, mentally retarded, and psychosis). All fatalities were attributable to hypothermia [20]. In another study, six out of twenty-nine patients died (21%) when search and rescue groups responded only after law enforcement search attempts were unsuccessful. Deceased patients appeared to have succumbed to hypothermia or drowned. Twelve patients (36%) were found alive but required evacuation. Based upon field diagnosis all the patients suffered from hypothermia and/or dehydration. DAT patients have usually wandered before, are generally unresponsive even when uninjured, leave few physical clues, and wander across roads [21].

Materials and Methods

The Virginia Department of Emergency Services (DES) is responsible for coordinating Search and Rescue (SAR) activities throughout the state. In 1986, DES introduced a new management system that uses selected operations personnel to handle