Topographical disorientation in Alzheimer's disease

Abstract

-Topographical disorientation (TD) has not been as extensively studied as other frequent manifestations of Alzheimer's disease (AD). Objective: To verify the occurrence of TD and to identify the neuropsychological dysfunctions associated with TD in AD. Method: Thirty patients with probable AD, their caregivers and 30 subjects without dementia (controls) were interviewed with a questionnaire and evaluated with tests related to topographical orientation. Results: AD patients, even those with mild dementia, differ from controls in the questionnaire on topographical orientation and in most neuropsychological tests except for tests of spatial working memory, point localization, three dimension and nonsense figure copy. When the performances in the neuropsychological tests of patients with mild or moderate dementia were compared, only landmark recognition and route description were more impaired in moderate dementia. Conclusion: TD occurs even in mild dementia of AD, a finding apparently not explained by the impairments of more elementary spatial functions.Key WorDs: Alzheimer's disease, orientation, spatial perception, topographical disorientation, spatial working memory. Desorientação topográfica na doença de AlzheimerResumo -Desorientação topográfica (DT) não tem sido tão exaustivamente estudada quanto outros sintomas frequentes da doença de Alzheimer (DA). Objetivo: Verificar a ocorrência de DT e identificar as disfunções neuropsicológicas associadas com a DT na DA. Método: Trinta pacientes com DA provável, seus cuidadores e trinta sujeitos sem demência (controles) foram entrevistados com um questionário e testes relacionados à orientação topográfica. Resultados: Pacientes com DA, mesmo aqueles com demência leve, diferiram dos controles no questionário de orientação topográfica e na maioria dos testes neuropsicológicos, exceto nos testes memória operacional espacial, localização de pontos, cópia de figuras sem sentido e de figura em três dimensões. Quando os desempenhos de pacientes com demência leve ou moderada foram comparados, apenas os testes de reconhecimento de marcos e descrição de rotas foram mais comprometidos na demência moderada. Conclusão: DT ocorre mesmo na demência leve da DA, um achado aparentemente não explicado pelo comprometimento das funções espaciais mais elementares.PAlAVrAs-ChAVe: doença de Alzheimer, orientação topográfica, desorientação topográfica, percepção espacial, memória operacional espacial.

Everyday episodic memory in amnestic mild cognitive impairment: a preliminary investigation

“…The geographical disorientation found on the Route Description task in the MCI group occurred despite the provision of cardinal directions and a clear map of the imaginary city. This finding is important, as similar decrements in route description have been observed in the mild stages of AD and these deficits are attributed to allocentric disorientation [38]. …”

“…Importantly, whilst sex was not evenly distributed between the participant groups, the over-representation of males in the MCI group did not mask the significant spatial memory deficits found in this cohort compared with controls. The relative sparing of spatial recognition memory in MCI warrants further attention, particularly where the functional capacity of the individual is concerned, given that topographical disorientation is often one of the initial manifestations of AD [38,41] and likely contributes to the compromised capacity to carry out such activities of daily living as shopping and travelling unaccompanied.…”

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What is the role of spatial processing in the decline of episodic memory in Alzheimer’s disease? The “mental frame syncing” hypothesis

“…In addition to episodic memory impairment, a decline in spatial memory is one of the earliest clinical manifestations of AD (Henderson et al, 1989; Passini et al, 1995; Cherrier et al, 2001; Monacelli et al, 2003; Guariglia and Nitrini, 2009; Laczó et al, 2011; Gazova et al, 2012; Lithfous et al, 2013). …”