title: Gender disparity in subcortical encoding of binaurally presented speech stimuli: an auditory evoked potentials study.
abstract: OBJECTIVE
  To investigate the influence of gender on subcortical representation of speech acoustic parameters where simultaneously presented to both ears.
  
  
  METHODS
  Two-channel speech-evoked auditory brainstem responses were obtained in 25 female and 23 male normal hearing young adults by using binaural presentation of the 40 ms synthetic consonant-vowel/da/, and the encoding of the fast and slow elements of speech stimuli at subcortical level were compared in the temporal and spectral domains between the sexes using independent sample, two tailed t-test.
  
  
  RESULTS
  Highly detectable responses were established in both groups. Analysis in the time domain revealed earlier and larger Fast-onset-responses in females but there was no gender related difference in sustained segment and offset of the response. Interpeak intervals between Frequency Following Response peaks were also invariant to sex. Based on shorter onset responses in females, composite onset measures were also sex dependent. Analysis in the spectral domain showed more robust and better representation of fundamental frequency as well as the first formant and high frequency components of first formant in females than in males.
  
  
  CONCLUSIONS
  Anatomical, biological and biochemical distinctions between females and males could alter the neural encoding of the acoustic cues of speech stimuli at subcortical level. Females have an advantage in binaural processing of the slow and fast elements of speech. This could be a physiological evidence for better identification of speaker and emotional tone of voice, as well as better perceiving the phonetic information of speech in women.
authors.affiliation: Department of Audiology, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Ahadi
authors.affiliation: Department of Audiology, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran; Rehabilitation Research Center, Iran University of Medical Sciences, Tehran, Iran. Electronic address: a-pourbakht@tums.ac.ir.
authors.forename: Akram
authors.initials: A
authors.lastname: Pourbakht
authors.affiliation: Medical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Research Center of Biomedical Technology and Robotics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Homayoun
authors.initials: AH
authors.lastname: Jafari
authors.affiliation: Medical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Shirjian
authors.affiliation: Medical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Salar
authors.initials: AS
authors.lastname: Jafarpisheh
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001933:Brain Stem / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012737:Sex Factors; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
keywords: Auditory brainstem response; Brain stem; Gender; Speech