Pakhomov Serguei V S, Kaiser Eden A, Boley Daniel L, Marino Susan E, Knopman David S, Birnbaum Angela K
Center for Clinical and Cognitive Neuropharmacology, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414, USA.
J Neurolinguistics. 2011 Oct;24(6):619-635. doi: 10.1016/j.jneuroling.2011.06.002.
Spontaneous speech of healthy adults consists of alternating periods of fluent and hesitant segments, forming temporal cycles in speech fluency. The regularity of these cycles may be related to the functioning of brain networks during speech planning and execution. This paper investigates the theoretical link between human cognitive functioning and temporal cycles in speech production using a quantitative time series analysis to characterize the regularity and frequency of temporal cycles in adults with differing levels and etiology of cognitive decline. We compare spontaneous speech of adults without a neurological diagnosis, both older and younger, to that of adults with frontotemporal lobar degeneration (FTLD). Two measures of temporal cycle frequency (mean and mode) calculated from the power spectrum of speech fluency represented as a time series were found to be associated with subjects' age, regardless of diagnosis of dementia. Two measures of periodicity (g-statistic and rhythmicity-index), as well as mean frequency, differentiated between adults with and without dementia. Our study confirms the presence of regular temporal cycles in spontaneous speech and suggests that temporal cycle characteristics are affected in different ways by declines in cognitive functioning due to dementia and aging.
健康成年人的自发言语由流利和犹豫片段交替出现的时期组成，在言语流畅性方面形成时间周期。这些周期的规律性可能与言语规划和执行过程中大脑网络的功能有关。本文使用定量时间序列分析来表征认知衰退程度和病因不同的成年人言语时间周期的规律性和频率，研究人类认知功能与言语产生时间周期之间的理论联系。我们将未患神经疾病的成年人（包括老年人和年轻人）的自发言语与额颞叶痴呆（FTLD）患者的自发言语进行比较。从作为时间序列表示的言语流畅性功率谱计算出的两个时间周期频率指标（均值和众数）被发现与受试者的年龄相关，无论其是否患有痴呆症。两个周期性指标（g统计量和节律性指数）以及平均频率，能够区分患有和未患有痴呆症的成年人。我们的研究证实了自发言语中存在规律的时间周期，并表明由于痴呆和衰老导致的认知功能衰退以不同方式影响时间周期特征。
