Limits...
Late, not early mismatch responses to changes in frequency are reduced or deviant in children with dyslexia: an event-related potential study.

Halliday LF, Barry JG, Hardiman MJ, Bishop DV - J Neurodev Disord (2014)

Bottom Line: However, findings have been inconsistent, both for behavioural and electrophysiological measures.Conventional analyses revealed no significant differences between groups in the size of the MMN to either large or small frequency deviants.Rather, deficits in late-stage auditory processing appear to be a feature of this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Psychology and Language Sciences, University College London, 2 Wakefield Street, London WC1N 1PF, UK ; Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK.

ABSTRACT

Background: Developmental disorders of oral and written language have been linked to deficits in the processing of auditory information. However, findings have been inconsistent, both for behavioural and electrophysiological measures.

Methods: In this study, we examined event-related potentials (ERPs) in 20 6- to 14-year-old children with developmental dyslexia and 20 age-matched controls, divided into younger (6-11 years, n = 10) and older (11-14 years, n = 10) age bands. We focused on early (mismatch negativity; MMN) and late (late discriminative negativity; LDN) conventional mismatch responses and associated measures derived from time-frequency analysis (inter-trial coherence and event-related spectral perturbation). Responses were elicited using an auditory oddball task, whereby a stream of 1000-Hz standards was interspersed with rare large (1,200 Hz) and small (1,030 Hz) frequency deviants.

Results: Conventional analyses revealed no significant differences between groups in the size of the MMN to either large or small frequency deviants. However, the younger age band of children with dyslexia showed an enhanced inter-trial coherence in the theta frequency band over the time window corresponding to the MMN to small deviants. By contrast, these same children showed a reduced-amplitude LDN for the small deviants relative to their age-matched controls, whilst the older children with dyslexia showed a shorter and less intense period of event-related desynchronization over this time window.

Conclusions: Initial detection and discrimination of auditory frequency change appears normal or even enhanced in children with dyslexia. Rather, deficits in late-stage auditory processing appear to be a feature of this population.

No MeSH data available.


Related in: MedlinePlus

Topographic headplots showing averaged weightings of electrodes on the first principal component. Subplots divided according to DYS status and age band; arbitrary scaling from negative (blue) to positive (red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4126817&req=5

Figure 1: Topographic headplots showing averaged weightings of electrodes on the first principal component. Subplots divided according to DYS status and age band; arbitrary scaling from negative (blue) to positive (red).

Mentions: We followed the procedure of Bishop et al. [23,48] and used the first spatial principal component to represent the auditory ERP. The mean weights from each channel contributing to the principal component for each subgroup are shown in headplots in Figure 1. Consistent with Bishop et al. [23,48], these indicated a fronto-central distribution that was similar between groups and across age groups, although slightly more left-lateralized in the dyslexic group, and particularly the older DYS subgroup.


Late, not early mismatch responses to changes in frequency are reduced or deviant in children with dyslexia: an event-related potential study.

Halliday LF, Barry JG, Hardiman MJ, Bishop DV - J Neurodev Disord (2014)

Topographic headplots showing averaged weightings of electrodes on the first principal component. Subplots divided according to DYS status and age band; arbitrary scaling from negative (blue) to positive (red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4126817&req=5

Figure 1: Topographic headplots showing averaged weightings of electrodes on the first principal component. Subplots divided according to DYS status and age band; arbitrary scaling from negative (blue) to positive (red).
Mentions: We followed the procedure of Bishop et al. [23,48] and used the first spatial principal component to represent the auditory ERP. The mean weights from each channel contributing to the principal component for each subgroup are shown in headplots in Figure 1. Consistent with Bishop et al. [23,48], these indicated a fronto-central distribution that was similar between groups and across age groups, although slightly more left-lateralized in the dyslexic group, and particularly the older DYS subgroup.

Bottom Line: However, findings have been inconsistent, both for behavioural and electrophysiological measures.Conventional analyses revealed no significant differences between groups in the size of the MMN to either large or small frequency deviants.Rather, deficits in late-stage auditory processing appear to be a feature of this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Psychology and Language Sciences, University College London, 2 Wakefield Street, London WC1N 1PF, UK ; Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK.

ABSTRACT

Background: Developmental disorders of oral and written language have been linked to deficits in the processing of auditory information. However, findings have been inconsistent, both for behavioural and electrophysiological measures.

Methods: In this study, we examined event-related potentials (ERPs) in 20 6- to 14-year-old children with developmental dyslexia and 20 age-matched controls, divided into younger (6-11 years, n = 10) and older (11-14 years, n = 10) age bands. We focused on early (mismatch negativity; MMN) and late (late discriminative negativity; LDN) conventional mismatch responses and associated measures derived from time-frequency analysis (inter-trial coherence and event-related spectral perturbation). Responses were elicited using an auditory oddball task, whereby a stream of 1000-Hz standards was interspersed with rare large (1,200 Hz) and small (1,030 Hz) frequency deviants.

Results: Conventional analyses revealed no significant differences between groups in the size of the MMN to either large or small frequency deviants. However, the younger age band of children with dyslexia showed an enhanced inter-trial coherence in the theta frequency band over the time window corresponding to the MMN to small deviants. By contrast, these same children showed a reduced-amplitude LDN for the small deviants relative to their age-matched controls, whilst the older children with dyslexia showed a shorter and less intense period of event-related desynchronization over this time window.

Conclusions: Initial detection and discrimination of auditory frequency change appears normal or even enhanced in children with dyslexia. Rather, deficits in late-stage auditory processing appear to be a feature of this population.

No MeSH data available.


Related in: MedlinePlus