Time and language--critical remarks on diagnosis and training methods of temporal-order judgment

A lively discussion concerning the causal relation between auditory temporal processing and phoneme identification has evolved over the last decades. Subjects with language impairments not only show deficits in the identification of stop-consonant vowel syllables, but also have problems detecting the temporal order of acoustic stimuli. Recently published studies claim that an improvement in phoneme discrimination can be achieved through the training of temporal-processing abilities. Critical assessment of these studies often reveals the following weaknesses: first, the diagnostic and training methods vary between studies, which makes comparisons difficult. Second, usually only mean differences between groups or before/after treatment are presented. The success in diagnosis and training of individuals or subgroups is not documented. Third, only few diagnostic measures employed have been tested for reliability. Furthermore, the tests have not been designed according to modern psychometric methods. Fourth, several training modules are used in parallel. The effects of temporal-processing training cannot be isolated. Possible approaches for detecting the possible causal relation between the time and the language domain are discussed.