title: Duration and numerical estimation in right brain-damaged patients with and without neglect: Lack of support for a mental time line.
abstract: Previous studies have shown that left neglect patients are impaired when they have to orient their attention leftward relative to a standard in numerical comparison tasks. This finding has been accounted for by the idea that numerical magnitudes are represented along a spatial continuum oriented from left to right with small magnitudes on the left and large magnitudes on the right. Similarly, it has been proposed that duration could be represented along a mental time line that shares the properties of the number continuum. By comparing directly duration and numerosity processing, this study investigates whether or not the performance of neglect patients supports the hypothesis of a mental time line. Twenty-two right brain-damaged patients (11 with and 11 without left neglect), as well as 11 age-matched healthy controls, had to judge whether a single dot presented visually lasted shorter or longer than 500 ms and whether a sequence of flashed dots was smaller or larger than 5. Digit spans were also assessed to measure verbal working memory capacities. In duration comparison, no spatial-duration bias was found in neglect patients. Moreover, a significant correlation between verbal working memory and duration performance was observed in right brain-damaged patients, irrespective of the presence or absence of neglect. In numerical comparison, only neglect patients showed an enhanced distance effect for numerical magnitude smaller than the standard. These results do not support the hypothesis of the existence of a mental continuum oriented from left to right for duration. We discuss an alternative account to explain the duration impairment observed in right brain-damaged patients.
authors.affiliation: Psychological Sciences Research Institute and Institute of Neuroscience, Catholic University of Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Masson
authors.affiliation: Psychological Sciences Research Institute and Institute of Neuroscience, Catholic University of Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Mauro
authors.initials: M
authors.lastname: Pesenti
authors.affiliation: Psychological Sciences Research Institute and Institute of Neuroscience, Catholic University of Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Valérie
authors.initials: V
authors.lastname: Dormal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001288:Attention; D001930:Brain Injuries / Q000523:psychology*; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual; D011597:Psychomotor Performance; D012044:Regression Analysis; D013998:Time Perception
keywords: duration; mental time line; numerosity; spatial neglect; working memory