Abstract
Purposes: The study sets the stage for temporal information processing as a fundamental basis of human cognition and a novel neurorehabilitation method. We focus on auditory perception of temporal order and address the following questions: (1) do subjects' age, gender, hearing status and cognitive functioning influence temporal ordering abilities; (2) are there any differences between Polish and German subjects on these abilities?
Methods: 86 Polish and 82 German subjects aged from 20 to 69 years were classified into 5 age groups. Subjects identified the order of two 1-ms clicks presented monaurally in rapid succession. The temporal order threshold (i.e. the minimum temporal gap required to report the stimulus order at 75% correctness) was assessed for each individual.
Results: There were no differences between Polish and German subjects on temporal ordering. In both samples, a significant prolongation of temporal-order threshold was observed in subjects older than 60 years of age. Temporal processing was relatively resistant to subjects' hearing status, but it depended on cognitive competence. Thus, it is not chronological age as such but cognitive competence that may explain age-related decreases of temporal acuity. Furthermore, potential effects of age or gender are robust against the language background as no differences were observed between Polish and German subjects.
Conclusions: We propose the existence of a neural mechanism underlying the perception of rapid changes in non-verbal acoustic features which constitute a frame for speech perception in many languages. This finding may be important with respect to future applications of temporal training in speech therapy programs designed for patients with receptive language disorders of different etiologies.