["Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterised by a triad of motor, psychiatric and cognitive deficits with the latter classically attributed to disruption of frontostriatal networks. However, emerging evidence from animal models of HD suggests that some of the early cognitive deficits may have a hippocampal basis. The objective of this study was to link previous rodent findings in this area to clinical practice.", 'In this study, 94 participants included patients with early HD, premanifest HD and age-matched controls underwent hippocampal-based cognitive assessments. These included a virtual reality version of the Morris water maze, a task involved participants having to swim through a virtual pool to find a submerged platform using a joystick, and the Cambridge Neuropsychological Test Automated Battery (CANTAB) paired associates learning task, a test also known to rely on hippocampal integrity.', 'Patients with early HD showed impaired performance in both the virtual Morris water maze and the CANTAB paired associates learning. Such deficits were also correlated with estimated years to diagnosis in premanifest participants.'] Does hippocampal dysfunction define disease onset in Huntington 's disease?