Always Getting Lost: Defining Developmental Topographical Disorientation (DTD)-A Systematic Literature Review.

Developmental topographical disorientation (DTD) refers to a condition of highly impaired navigation ability in healthy individuals. DTD often leads to severe consequences in daily life, affecting education and professional choices and limited everyday mobility. Since its first description in 2009, a substantial number of empirical studies on DTD have appeared, but a clear clinical definition of DTD that can be used to develop a behavioral assessment tool is not yet available. The aim of the current study was to shed more light on the precise behavioral characteristics of DTD by examining the empirical evidence available to date. Recent theoretical developments that enable the classification of navigation impairment in various populations are utilized in the current work. Through a systematic literature review, reported descriptions and criteria for DTD were identified. Furthermore, tests included and performance of people with DTD are classified in the different navigation domains relevant to navigation impairment (landmark knowledge; location knowledge, egocentric and allocentric; and path knowledge, route and survey). A total of 15 empirical papers were included in the analyses, each discussing performance of people with DTD in large-scale spatial tasks. Initial DTD descriptions focused on mental map quality, whereas later work adheres to a more general definition of impaired navigation. Performance patterns show that the navigation impairment in DTD is largely attributable to low mental map quality, as low performance is primarily found for tasks measuring allocentric location knowledge and path knowledge. In contrast, landmark knowledge remains largely unaffected and, if impaired, appears to also include face recognition impairment, suggesting a more general form of visual agnosia. Egocentric location knowledge is often not included in assessments. The outcomes support the initial focus on poor mental map quality as the key characteristic of DTD, combined with a landmark-focused navigation strategy. The current findings therefore provide relevant input to the development of a clinical characterization of DTD and the development of appropriate assessment tools.