Preamble and Problem Statement The increasing prevalence of neurodegenerative dementia disorders in aging societies results in a proportional rise in missing person cases within this vulnerable population. The search for these individuals presents rescue organizations, particularly highly specialized search and rescue (SAR) dog units, with extraordinary and multidimensional challenges that extend far beyond standard person search protocols. The behavioral repertoire of people with dementia is characterized by a complex interplay of progressive neurocognitive deficits, neuropsychiatric symptoms (Behavioral and Psychological Symptoms of Dementia, BPSD), comorbid physical illnesses, and the resulting unmet needs. A profound, interdisciplinary, and scientifically substantiated understanding of this pathophysiology and its phenotypic manifestations is not merely a methodological necessity but an ethical imperative to maximize the efficiency and effectiveness of SAR dog deployments and substantially increase the probability of survival for those affected – often a matter of hours. This extended paper aims to comprehensively illuminate the neurocognitive, behavioral ecological, and operational-tactical dimensions of this issue and to derive detailed, evidence-based measures for SAR dog units.
I. Neurocognitive and Behavioral Ecological Determinants of the Search Scenario in Dementia The specific characteristics of dementia disorders modify search conditions for SAR dogs in a way that makes adaptation of standard search doctrines imperative.
A. Detailed Neurobiological Foundations and their Implications for the Scent Trail and Search Behavior
1. Topographic Disorientation and Amnesia in Alzheimer’s Disease (AD) and Vascular Dementia (VaD):
- Neurobiology (AD): Alzheimer’s disease is neuropathologically defined primarily by the accumulation of extracellular amyloid-β plaques and intracellular neurofibrillary tangles (hyperphosphorylated tau protein). These pathologies lead to selective vulnerability and progressive loss of neurons and synapses, particularly in the medial temporal lobe, beginning in the entorhinal cortex and hippocampus (Braak & Braak, 1991; Braak & Braak, 1995). These regions are integral to the formation and retrieval of episodic and spatial memory content. The hippocampus houses place cells, which encode specific locations in an environment, while the entorhinal cortex contains grid cells, providing a metric system for spatial navigation (O’Keefe & Nadel, 1978; Moser et al., 2008; Hafting et al., 2005). The failure of these systems leads to the inability to create or retrieve a coherent cognitive map (topographagnosia) and to anterograde and retrograde amnesia.
- Neurobiology (VaD): Vascular dementia results from cerebrovascular damage, such as multi-infarct dementia, strategic single infarcts, or subcortical ischemic vasculopathy (e.g., Binswanger’s disease) with extensive white matter lesions (WMLs). These lesions interrupt critical cortico-subcortical circuits responsible for executive functions, attention, and processing speed, which secondarily also impairs spatial orientation and navigation, often through disruption of information integration or the ability for strategic route finding.
- Implication for SAR Dogs: The disintegration of the cognitive map and loss of goal-directedness lead to erratic movement patterns. The “Circuitous/Looped Travel” patterns described by Koester (2008) are typical. The scent trail is therefore often non-linear, characterized by recursions, abrupt changes in direction, and a high density of scent particles in narrowly confined zones (where the person may have remained disoriented or circled). For Mantrailers, this necessitates the ability to discriminate extremely subtle scent differences to avoid following older sections of the same trail or being misguided by overlaps. The interpretation of the trail’s intensity and age becomes critical.
2. Impairments of Executive Functions and Inadequate Problem-Solving and Risk Behavior (AD, VaD, FTD):
- Neurobiology: Executive functions (planning, organization, working memory, inhibition, cognitive flexibility, decision-making) are primarily linked to the integrity of the prefrontal cortex and its connections to other cortical and subcortical areas (Béland et al., 2009; Miller & Cohen, 2001). In later stages of AD, the pathology spreads to frontal association cortices. In VaD, strategic infarcts in the frontal lobe or interruptions of fronto-subcortical circuits can directly damage executive functions. In Frontotemporal Dementia (FTD), particularly the behavioral variant (bvFTD), the prefrontal and anterior temporal cortex are primarily affected.
- Implication for SAR Dogs: The inability to adequately assess risks or develop adaptive problem-solving strategies leads individuals with dementia to often follow linear landscape features such as roads, paths, fences, hedges, or streams (“Obstacle Following/Avoidance” or “Boundary Following”) (Rowe et al., 2012; Koester, 2008). These structures offer a deceptive perceptual security or represent the path of least resistance. The scent trail will therefore predictably be found along such lines, allowing for a focusing of search resources. However, executive dysfunctions can also lead to unpredictable behavior, such as entering dangerous areas (e.g., busy roads, bodies of water) without perceiving the danger. The dog must also reliably work faint trails away from these lines that indicate a sudden, poorly planned change of direction.
3. Fluctuating Cognition, Vigilance Fluctuations, and Situational Awareness Impairment (Lewy Body Dementia – DLB):
- Neurobiology: DLB is characterized by the deposition of alpha-synuclein protein aggregates (Lewy bodies and Lewy neurites) in the cortex, limbic system, and brainstem. The pronounced fluctuations in cognition and vigilance are associated with cholinergic and dopaminergic deficits, particularly due to dysfunction of the ascending reticular activating system and cortical cholinergic pathways (Ferman et al., 2014; Perry et al., 1990).
- Implication for SAR Dogs: The scent trail may be consistent and extensive during phases of relative clarity and mobility. However, with the sudden onset of somnolence, apathy, or confusion, the person may abruptly stop, lie down, or remain in one place for an extended period. This leads to a sudden termination of the dynamic trail and a concentration of scent particles in a narrowly confined location. Handlers must interpret the dog’s indication with extreme sensitivity: is the dog signaling the end of an active trail and a transition to a “point of rest” or a hiding situation? This requires the ability to seamlessly switch from dynamic trailing (Mantrailing) to intensive close-quarters or area searching (air scenting).
4. Recurrent Visual Hallucinations, Delusions, and Emotional Lability (DLB, partly AD):
- Neurobiology: Visual hallucinations in DLB are often complex, detailed, and vivid (people, animals, objects). They are associated with dysfunctions in the visual association cortex, cholinergic deficits, and disturbed REM sleep regulation (McKeith et al., 2005; Harding et al., 2002). Delusions (e.g., persecutory, theft, jealousy) can also occur and are often linked to the hallucinations or general cognitive impairment.
- Implication for SAR Dogs: A person acting based on hallucinations or delusions (e.g., fleeing an imagined threat) may lay a very direct, fast, and potentially extensive scent trail (“Flight Response,” “Straight Line Travel”). They may also hide in extremely unusual, inaccessible, or objectively dangerous places to escape the perceived threat. The dog must be able to follow such fast, linear trails and also indicate minute scent cues in atypical hiding spots (e.g., high up, deep down, in narrow crevices). The emotional state can influence the intensity of scent emission (stress hormones).
5. Parkinsonian Motor Symptoms and Mobility Limitations (DLB, VaD with subcortical lesions, advanced AD):
- Neurobiology: Extrapyramidal motor symptoms (bradykinesia, rigidity, postural instability, gait disturbances) in DLB result from alpha-synuclein pathology in nigrostriatal pathways (McKeith et al., 2005). In VaD, subcortical lesions can cause similar symptoms. Motor impairments can also occur in advanced stages of AD.
- Implication for SAR Dogs: Limited mobility leads to a shorter, often dragging scent trail with less extension. Stride length is reduced, speed is low. The probability of finding the person in close proximity to the “Point Last Seen” (PLS) or exhausted after a short distance increases. Immobility elevates the risk of exposure (hypothermia, hyperthermia, pressure sores), exacerbating time criticality. Handlers must consider the missing person’s physical capacity when interpreting trail length and characteristics. A short trail does not necessarily mean vehicle transfer but can reflect severe immobility.
6. Personality, Behavioral, and Language Disorders (Frontotemporal Dementia – FTD):
- Neurobiology: FTD is a heterogeneous group of disorders involving atrophy of the frontal and/or temporal lobes. The behavioral variant (bvFTD) is characterized by personality changes such as disinhibition, apathy, loss of empathy, compulsive-stereotypical behaviors, and executive dysfunctions (Neary et al., 1998; Rascovsky et al., 2011). Primary progressive aphasia (PPA) manifests in various language disorders.
- Implication for SAR Dogs: Impulsive, disinhibited actions can lead the person into socially inappropriate or dangerous, publicly inaccessible areas (e.g., private properties, industrial sites, railway tracks), which means extremely difficult terrain and high contamination for search dogs. Apathy can cause the person not to respond to calls or the approach of search teams, severely impairing the effectiveness of area search dogs trained for acoustic or interactive indications. Dogs with very precise, passive alerts or bringsel indications are superior here. Stereotypical, repetitive movements (e.g., constant pacing in a small area) create extremely dense, overlapping scent trails in narrowly confined, often circular areas, posing a challenge for Mantrailers in terms of resolution.
B. Specific, Multidimensional Challenges for SAR Dog Deployment The neurocognitive and behavioral ecological patterns outlined above culminate in a series of specific challenges:
- Hypercomplexity and extreme variability of the scent trail: Scent trails are not only shaped by the aforementioned patterns but also by individual factors such as medication (which can alter body odor), hygiene habits, and the specific disease progression. Distinguishing between fresh and older trail sections during recursions requires the highest olfactory discrimination performance from the dog and excellent interpretation skills from the handler.
- Dramatic time criticality (“Golden 24/12/6 Hours”): While the “Golden 24 Hours” is a general benchmark (Koester, 2008), the survival probability for individuals with dementia often decreases even more rapidly due to their increased vulnerability to dehydration, hypo-/hyperthermia, falls, and missed essential medication (Buglass et al., 2011). In adverse weather conditions, even 6-12 hours can be critical. This demands immediate and maximally prioritized alert and operational readiness.
- Atypical and often illogical hiding behavior: Fear, confusion, the desire for protection from imagined threats, or regressive behavior can lead the person to hide in extremely atypical, hard-to-see, and often dangerous locations (Rossmo & Van Blaricom, 2008). This ranges from under vehicles, in garbage cans, narrow utility shafts, to treetops or water drains. Dogs must be trained to indicate even minimal scent sources in such places and not be deterred by the improbability of the hiding spot.
- Minimal to no cooperation and communication upon finding: The missing person is unlikely to respond adequately to calls from search teams or the approach of a dog, and may be anxious, aggressive, or completely apathetic. This requires specialized indication behaviors from the dogs (e.g., calm alert from a distance, barking without harassment, bringseling) and psychologically trained handlers for de-escalating initial contact and securing the person.
- Significant influence of environmental factors and terrain: Rain, wind, extreme temperatures, and high humidity massively affect the persistence, distribution, and trackability of scent trails. Dense vegetation, urban development (heat islands, wind tunnels, scent contamination from traffic and other people), and difficult terrain (steep slopes, bodies of water, industrial brownfields) can hinder the spread of human scent (relevant for area search dogs) or fragment and contaminate the trail for Mantrailers.
II. Strategic-Tactical Imperatives and Required Measures for SAR Dog Units: An Integrated and Evidence-Based Approach Given the complexity described, SAR dog deployments for missing persons with dementia require comprehensive measures that go beyond standard procedures and are scientifically founded.
A. Pre-hospital Crisis Management, Prevention, and Optimized Information Acquisition: The Basis for Operational Success
1. Implementation of Staged Early Warning Systems and Rigorous Prioritization Protocols:
- Standardized emergency protocols with escalation levels: Development and implementation of binding protocols in integrated control centers, police, and emergency services that automatically classify the report of a missing person with diagnosed dementia as an operation of the highest urgency (e.g., “Immediate Deployment – Person in Life-Threatening Danger”). This must trigger immediate, parallel alerting of qualified SAR dog units (Mantrailers and area search dogs), police (including helicopters with thermal imaging cameras – TICs), and, if necessary, other specialized SAR units (e.g., drones with TICs/zoom, cave/water rescue in appropriate terrain).
- Cultivation of a “Zero-Delay” principle and “Golden Hours” awareness: Intensive, recurrent training and sensitization of all involved stakeholders (from relatives and caregivers to first reporters and emergency responders) about the extreme time criticality and the mechanisms of physiological destabilization in individuals with dementia. The goal is to minimize any conceivable delay in the alert and deployment chain.
2. Multidimensional, Dementia-Specific Information Gathering and Analysis (Advanced Initial Assessment):
- Structured, qualified initial interview by trained personnel: Team leaders or specially qualified dog handlers must conduct an in-depth, structured initial assessment. This must go far beyond standard questions and delve deeply into the individual characteristics of the dementia, pre-dementia personality structure, biographical aspects, and current behavioral patterns. Standardized checklists covering dementia-specific aspects should be developed and used for this purpose.
- Exact verification of Time and Point Last Seen (TLS/PLS): Indispensable for the precise dynamic calculation of the Probability of Survival (POS) and the definition of the initial search radius based on established models (e.g., Koester’s Lost Person Behavior statistics, adapted for dementia profiles).
- Detailed collection of life routines, preferences, and biographically significant locations: Systematic inquiry about former places of residence, workplaces, regularly visited places (shops, churches, parks), favorite walking routes, places with strong emotional or biographical significance (e.g., childhood home, place where a partner was met). Such places can act as “attractors,” even if they are far from the current residence or PLS. Mantrailers can be specifically deployed here (Scent Specific Searches to Destination).
- Analysis of potential triggers for “wandering” behavior: Were there specific stressors, changes in routine, unmet needs (hunger, thirst, need to use the toilet, pain), boredom, an attempt to perform a “task” (e.g., “go to work,” “pick up children”), or did the typical “sundowning” syndrome (late-day agitation) manifest? This information can provide clues about motivation, emotional state, and the likely initial direction of movement.
- Comprehensive clinical and functional status: Recording of the type and stage of dementia, communication skills (active/passive), medication plan (especially time-critical drugs like insulin, Parkinson’s medication, antiepileptics), current physical condition, mobility limitations (walking aids, wheelchair, arthritis, previous fractures, strokes with paresis, vision and hearing impairments). These parameters are crucial for assessing the possible range, speed, type of terrain to be searched, and the urgency of medical care after finding.
- Detailed description of clothing and items carried: Including possible changes of clothes. Inquiring about personal items carried (keys, wallet, ID papers, mobile phone – even if often inoperable) provides clues about identification possibilities, degree of preparation, and potential interactions (e.g., use of public transport).
- Recording of previous missing person episodes: Analysis of patterns, distances traveled, locations found, and behavior during previous incidents.
3. Proactive Establishment and Management of Scent Reference Libraries:
- Standardized protocols for securing scent articles: SAR dog units should actively and repeatedly disseminate detailed, scientifically sound instructions to relatives, care facilities, and support services on how to prepare an odor-neutral and contamination-low reference item (e.g., an unwashed cotton T-shirt, socks, pillowcase worn directly against the body for several hours – secured in a sterile, airtight glass container or special odor-neutral bag, stored cool and dark) and have it immediately available in an emergency. The importance of an uncontaminated, person-specific reference item for the precision and speed of Mantrailing searches must be emphasized. Multiple articles from different days can be beneficial.
B. Adaptive Operational Strategies and Differentiated SAR Dog Unit Tactics: Tailored and Dynamic Search Operations
1. Implementation of Dynamic, Integrative, and Scenario-Adaptive Search Patterns:
- Mantrailing as the primary initial tactic with a known PLS: Given the need to follow a highly individual scent trail and clarify the initial direction of movement, Mantrailing (with qualified and certified teams) is often the method of first choice, especially in complex urban or suburban environments with high foreign scent contamination. Mantrailers can clarify the direction of departure and initial movement patterns, even if erratic, and identify “decision points” (intersections, turn-offs).
- Parallel or sequential, targeted area search (Air Scenting): If the point of departure is unclear, if the Mantrailer definitively loses the trail (e.g., due to vehicle pick-up, entering heavily contaminated areas, trail time limit), or if the person is very likely hiding in a defined area, systematic area search with specially trained area search dogs is essential. These dogs work “off-leash” searching for human air scent in their assigned sector. Sector allocation must consider LPB data and terrain specifics.
- Strategic prioritization and systematic search of linear features and “attractors”: Handlers should specifically and repeatedly deploy and train their dogs along roads, paths, fences, hedges, streams, forest edges, or railway lines (with appropriate safety precautions), as individuals with dementia are empirically shown to follow these structures (Koester, 2008; Rowe et al., 2012). Identified biographical “attractors” should also be searched as a priority, possibly by separate, rapidly deployed teams.
- Application of “Segmented Search Tactics” for long trails: For suspected long trails, it may be sensible to deploy Mantrailers not only from the PLS but also from probable points along the route (based on witness statements or LPB data) to save time (“Leapfrogging”).
2. High Specialization in Atypical Hiding Behavior and Hard-to-Access Locations:
- SAR dogs must be intensively and specifically trained to detect and precisely indicate even minimal scent particles in and at extremely atypical hiding places (e.g., under dense thorn bushes, in sewage drains, in trees, in garbage containers, under vehicles, in unsecured basements or attics of vacant buildings). Training must cover an immense range of possible hiding locations and scenarios, including the dog overcoming obstacles.
3. Competent Handling of Water Bodies, Heights, and Other Specific Risk Areas:
- SAR dogs, especially Mantrailers, must be trained to reliably follow trails to the edges of water bodies (rivers, lakes, ponds, canals) and clearly indicate entry into the water or loss of the trail at the water. This is vitally important due to the high risk of drowning for individuals with dementia (Lin et al., 2020). Specialized water search dogs can be deployed additionally if needed. The indication behavior for living and drowned persons should, if possible and depending on the dog’s training, be distinguishable or at least interpretable differently. Training on steep slopes, bridges, and other fall-risk locations is also necessary.
4. Optimization and Standardization of Night and Adverse Weather Operations:
- Given the “sundowning” phenomenon, frequent nighttime elopements, and increased exposure risk in darkness and cold, SAR dog teams must be optimally equipped for night operations (high-power, non-glare head and helmet lamps, GPS tracking for dogs and handlers, thermal imaging cameras for command/pre-reconnaissance) and intensively trained. This includes habituating dogs to light beams, shadows, and altered acoustic perceptions. Coordination with aerial units (police helicopters with FLIR/TICs), which can identify potential “hot spots” for ground teams, must be practiced and standardized.
C. Psychological Competence, Ethical Communication, and Dog-Specific Preparation in Deployment
1. In-depth Psychological and Gerontological Training for Handlers and Team Leaders:
- Handlers and team leaders require sound, up-to-date knowledge of the diverse symptoms, behaviors, emotional states, and communication capabilities of people with different forms and stages of dementia (AD, VaD, DLB, FTD). This includes detailed knowledge of direct behavioral effects (e.g., fluctuating cognition and agitation in DLB, impulsivity and disinhibition in bvFTD, apathy, anxiety, paranoid ideation).
- Intensive training in verbal and non-verbal techniques for de-escalation, trust-building contact, and person-centered communication is essential. This includes the practical application of principles from Validation Therapy according to Naomi Feil (Feil, 1992) to acknowledge and value the subjective reality and emotional needs of the found person, rather than correcting or confronting their altered perception of reality. Similarly, concepts of person-centered care according to Tom Kitwood (Kitwood, 1997) should be taught, focusing on maintaining personhood, dignity, and individual needs to minimize anxiety, stress, and agitation in the found person.
- Communication should always be calm, empathetic, non-confrontational, in short, simple sentences, and with positive body language. Direct, staring eye contact can be perceived as threatening and should be used adaptively. Education about typical fear reactions or aggressive behaviors and self-protection strategies are also part of the training.
2. Specific Preparation and Desensitization of the SAR Dog for Interaction with Individuals with Dementia:
- The dogs themselves must be specifically prepared for interacting with individuals who may be confused, have uncoordinated motor skills, suddenly change their volume or direction of movement, or react unexpectedly (e.g., defensively or embracingly). This includes systematic desensitization and habituation training to unusual movements, vocalizations, odors (e.g., due to incontinence), or the sight of walking aids or wheelchairs. The goal is to avoid unsettling or overwhelming the dog, ensuring a consistently calm, confident, reliable, and stress-free indication performance. The indication behavior must be trained so that it does not additionally frighten or harass the found person.
D. Systemic Interdisciplinary Cooperation, Technological Integration, and Continuous Scientific Development: A Learning System
1. Seamless and Institutionalized Integration into the Overall Societal SAR Process:
- SAR dog units must be recognized and integrated as an integral and indispensable component of the entire search and rescue process. This requires regular, realistic joint exercises and complex simulation scenarios with all relevant emergency service partners (police, fire department, medical emergency services, DLRG/Water Watch) and other SAR units (e.g., drone teams, technical locating services, aviation sports associations for aerial area search). The aim is to optimize interfaces, standardize communication protocols (digital/analog), establish clear command chains (e.g., under police leadership), and ensure smooth, resource-efficient coordination of diverse forces in the operational area.
2. Systematic Use and Integration of LPB Data, GIS Technology, and Predictive Modeling:
- Operational planning and command must routinely utilize the latest scientific findings from “Lost Person Behavior” research (e.g., the databases and analyses by Robert Koester). Search areas should be prioritized based on dementia-specific Probability of Detection (POD) and Probability Area (POA) maps to maximize success chances. Modern Geographic Information Systems (GIS) with integrated LPB overlays, digital terrain models, current aerial imagery, and the capability for real-time recording of search sectors and find locations should be standard equipment and confidently mastered by team leaders and planners. The development and use of predictive algorithms (possibly incorporating AI methods) to refine search strategies based on individual case parameters is a desirable goal.
3. Commitment to Continuous Research, Evidence-Based Further Education, and Quality Management:
- Research in the field of dementia, particularly on the neurocognitive modeling of wandering behavior, scent-specific aspects in dementia, and the effectiveness of search strategies, must be continuously advanced nationally and internationally, and the results transferred into practice. This also includes the development, validation, and implementation of new technologies (e.g., improved sensors, drone technology, data analysis tools).
- Regular, certified further education for handlers, team leaders, and all SAR personnel on the latest findings in dementia research, gerontopsychological approaches, communication techniques, operational tactics, GPS navigation, map work, and first aid (also specifically for geriatric emergencies) is essential to competently meet ever-evolving challenges. Establishment of quality management systems and regular audits to ensure the highest operational standards.
Synthesis and looking forward The successful deployment of SAR dogs in the search for missing persons with dementia represents one of the most demanding tasks in the entire spectrum of search and rescue services. It far transcends mere cynological performance and requires a profound, integrative understanding of medical, neurobiological, psychological, ethical, and tactical dimensions. Only through a holistic, evidence-based, interdisciplinary networked approach characterized by continuous learning – encompassing proactive prevention, optimized alert chains, highly specialized training for humans and animals, adaptive operational strategies, and interaction with affected individuals and their environment guided by empathy and professionalism – can SAR dog units optimally fulfill their indispensable role in protecting and rescuing people with dementia. Investment in research, training, and technology in this area is not just a matter of efficiency but an imperative of humanity and a societal obligation towards an ever-growing group of particularly vulnerable fellow human beings.