Lateralization Profile in ASD Children with Different Speech Development Levels

The lateralization profile and its link to speech development in 10 children with autism spectrum disorders and 20 neurotypical controls aged 6-7 were studied. Neuropsychological methods for the dominant arm, dominant ear, and dominant eye determination were used as well as for expressive and impressive speech assessment. Ambilateral results were found more often in autism spectrum disorders children compared to neurotypical controls. autism spectrum disorders children with ambilateral rates prevalence have shown higher results in speech development. There were more left ear dominance cases among autism spectrum disorders children compared with controls.

GIN (Gaps-In-Noise) Performance in the Pediatric Population

Background: The recently developed Gaps-In-Noise (GIN) test has provided a new diagnostic tool for the detection of temporal resolution deficits. Previous reports indicate that the GIN is a relatively sensitive tool for the diagnosis of central auditory processing disorder ([C]APD) in adult populations. Purpose: The purpose of the present study was to determine the feasibility of the GIN test in the pediatric population. Research Design: This was a prospective pseudorandomized investigation. Study Sample: This investigation involved administration of the GIN to 72 participants divided into six groups of normal children ranging from 7 through 18 years of age. Data Collection and Analysis: The approximate GIN threshold (the shortest gap duration for which at least four of six gaps were correctly identified) served as the dependent variable. Results were analyzed using an ANOVA to examine between- and within-group differences. Results: No statistically significant differences were seen in GIN thresholds among age groups. In addition, within group analysis yielded no statistically significant differences between ears within each age group. No developmental effect was seen in GIN thresholds between the ages of 7 and 18 years. Children as young as age 7 are able to complete the GIN with no significant difficulty and perform at levels commensurate with normal adults. The absence of ear differences suggests that temporal resolution as measured by the GIN is an auditory process that develops relatively early and symmetrically (i.e., no laterality or ear dominance effects). Conclusions: The GIN procedure appears to be a feasible measure of temporal resolution in both pediatric and adult populations.

From Dichoptic to Dichotic: Historical Contrasts between Binocular Vision and Binaural Hearing

Phenomena involving vision with two eyes have been commented upon for several thousand years whereas those concerned with hearing with two ears have a much more recent history. Studies of binocular vision and binaural hearing are contrasted with respect to the singleness of the percept, experimental manipulations of dichoptic and dichotic stimuli, eye and ear dominance, spatial localisation, and the instruments used to stimulate the paired organs. One of the principal phenomena that led to studies of dichotic hearing was dichoptic colour mixing. There was similar disagreement regarding whether colours or sounds could be combined when presented to different paired organs. Direction and distance in visual localisation were analysed before those for auditory localisation, partly due to difficulties in controlling the stimuli. Instruments for investigating binocular vision, like the stereoscope and pseudoscope, were invented before those for binaural hearing, like the stethophone and pseudophone.

EEG Correlates of Behavioural Laterality: Ear Dominance

To examine whether ear dominance in a dichotic pitch-discrimination task is associated with asymmetrical activation of the two cortical hemispheres, ear dominance scores and electroencephalographic (EEG) laterality were correlated in two independent samples ( ns = 46 and 128). The results indicate that ear dominance can partly be attributed to a relatively stronger activation of the contralateral prefrontal cortex. The observed association may reflect the tendency to direct attention preferably to one ear.

Ear Dominance and Telephone Sales

In a field study, three equally sized sales teams used one of three head-sets—left, right, both ears—for a day's selling of insurance by telephone. This had no effect on sales In a retrospective study of records, daily sales performance including the percentage conversion rate for sales divided by the number of calls and the number and duration of calls was related to preference for type of head-set. Sales were markedly influenced by the choice of head-set. People who chose to wear the left earpiece significantly out-sold the others wearing right and stereohead-sets. Neither the number of incoming calls nor the time spent on the telephone were influenced by the choice of head-set. When sales are analysed in terms of individual differences in personal preference for type of head-set, those who chose the left ear had an advantage. Forced use of the left, versus right ear or both ears for one day had no effect.

Effect of Music Training on Monaural Perception of Pitch and Rhythm

A monaural study of music perception was conducted on 77 right-handed subjects from a university population. The musical ability of each subject was classified in two ways, according to years of training and by total score for three tests of musical achievement [melody (sequence and excerpt), harmony, and rhythm]. Analysis indicated that subjects with more years of training showed a right-ear dominance for recognition of excerpts but those with high scores had no such dominance. Both groups with either low scores or no formal training had a right-ear dominance for recognition of sequences. Correlations of scores from each ear within subjects and between tests indicated that perception of pitch tended to be more accurate in the same ear. For all classifications of subjects no ear dominance was found for harmony and rhythm tests. These results suggest that the measurement of hemispheric asymmetry of music perception is dependent upon the criteria chosen for classification of subjects, in this case, training and achievement.