Stimulus dependence of the M100 latency in the age range 11-18 years

The latency of the major component of the auditory evoked neuromagnetic field, the M100 or N1m, is sensitive to acoustical and perceptual attributes of the presented stimulus [1-3]. In particular the latency depends upon stimulus intensity, frequency and spectral complexity. Thus latency variation has been proposed as an objective metric of hearing, complex sound processing and a number of clinical conditions in adults (e.g. tinnitus). Previous MEG studies have shown the 100ms component of the auditory evoked response to also have prolonged latency in children and teenagers [4]. Thus age may represent an additional factor in the description of latency variation, previously described, in some detail, in adults [2,3] as a function of stimulus attributes, such as stimulus intensity, acoustic structure and perceptual categorization. As such, latency measures in response to acoustic stimuli have a more complex interpretation in children. On the other hand, the age (development) dependent variation in evoked response latency may offer an objective instrument for the study and characterization of development in children and young adults. The accumulation of a normative database of evoked response latency as a function of stimulus acoustic complexity in children serves considerable value in the study of clinical sound processing and, in particular, developmental communication and language disorders, such as dyslexia, autism and attention deficit hyperactivity disorder.