TY - JOUR
T1 - Random local temporal structure of category fluency responses
AU - Meyer, David J.
AU - Messer, Jason
AU - Singh, Tanya
AU - Thomas, Peter J.
AU - Woyczynski, Wojbor A.
AU - Kaye, Jeffrey
AU - Lerner, Alan J.
N1 - Funding Information:
Acknowledgements This research has been supported by the U.S. National Science Foundation Grant “Interdisciplinary Training for Undergraduates in Biological and Mathematical Sciences” (DUE-0634612) administered by PJT; the first three authors were undergraduate students in biology and mathematics at Case while this work has been done. PJT was supported by the National Science Foundation’s program in Mathematical Biology (DMS-0720142), and acknowledges research support from the Oberlin College Libraries. JK was supported by grants from the National Institute on Aging (P30AG024978, P30AG08017 and R01AG024059).
PY - 2012/4
Y1 - 2012/4
N2 - The Category Fluency Test (CFT) provides a sensitive measurement of cognitive capabilities in humans related to retrieval from semantic memory. In particular, it is widely used to assess progress of cognitive impairment in patients with dementia. Previous research shows that, in the first approximation, the intensity of tested individuals' responses within a standard 60-s test period decays exponentially with time, with faster decay rates for more cognitively impaired patients. Such decay rate can then be viewed as a global (macro) diagnostic parameter of each test. In the present paper we focus on the statistical properties of the properly de-trended time intervals between consecutive responses (inter-call times) in the Category Fluency Test. In a sense, those properties reflect the local (micro) structure of the response generation process. We find that a good approximation for the distribution of the de-trended inter-call times is provided by the Weibull Distribution, a probability distribution that appears naturally in this context as a distribution of a minimum of independent random quantities and is the standard tool in industrial reliability theory. This insight leads us to a new interpretation of the concept of "navigating a semantic space" via patient responses.
AB - The Category Fluency Test (CFT) provides a sensitive measurement of cognitive capabilities in humans related to retrieval from semantic memory. In particular, it is widely used to assess progress of cognitive impairment in patients with dementia. Previous research shows that, in the first approximation, the intensity of tested individuals' responses within a standard 60-s test period decays exponentially with time, with faster decay rates for more cognitively impaired patients. Such decay rate can then be viewed as a global (macro) diagnostic parameter of each test. In the present paper we focus on the statistical properties of the properly de-trended time intervals between consecutive responses (inter-call times) in the Category Fluency Test. In a sense, those properties reflect the local (micro) structure of the response generation process. We find that a good approximation for the distribution of the de-trended inter-call times is provided by the Weibull Distribution, a probability distribution that appears naturally in this context as a distribution of a minimum of independent random quantities and is the standard tool in industrial reliability theory. This insight leads us to a new interpretation of the concept of "navigating a semantic space" via patient responses.
KW - Alzheimer's disease
KW - Category fluency test
KW - Cognitive impairment
KW - Inter response times
KW - Semantic memory
KW - Statistical temporal structure
KW - Weibull distribution
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U2 - 10.1007/s10827-011-0349-5
DO - 10.1007/s10827-011-0349-5
M3 - Article
C2 - 21739237
AN - SCOPUS:84863878412
SN - 0929-5313
VL - 32
SP - 213
EP - 231
JO - Journal of Computational Neuroscience
JF - Journal of Computational Neuroscience
IS - 2
ER -