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

ITC for difference waves in relation to DYS status and age band. Colours indicate range from zero (green) to 0.2 (deep red).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: ITC for difference waves in relation to DYS status and age band. Colours indicate range from zero (green) to 0.2 (deep red).

Mentions: Figures 4 and 5 show the mean levels of ITC, along with their spectral components, for mismatch waves in frequencies ranging from 1 to 20 Hz for the four subgroups. As described by Bishop et al. [23], the MMN region is characterized by a burst of increased ITC that is particularly marked in frequencies below 10 Hz. Visual inspection suggested that the DYS groups showed greater synchronization of these frequencies during the MMN time window relative to the controls. To explore this further, we compared the mean ITC in the first half of the trial (0–300 ms) between groups for the small and large deviants (see Table 2). Repeated measures ANCOVA revealed a significant three-way interaction between DYS status, age band, and deviant size, F(1, 35) = 4.61, p = 0.039. To explore this interaction, we first divided the sample into younger and older age bands. Repeated measures ANCOVA showed that for the older age band, the DYS group showed larger ITCs than the TD group, regardless of deviant size, F(1, 18) = 12.93, p = 0.002. However, for the younger age band, there was a significant interaction between DYS status and deviant size, F(1, 18) = 6.53, p = 0.020. Follow-up t tests showed that whereas there was no significant difference between the younger DYS and TD groups in the size of their ITC to the large deviant, t(1, 18) = 1.34, p = 0.198, the younger DYS group had a significantly larger ITC than the younger TD group in response to small deviants, t(1, 18) = -3.27, p = 0.004.


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)

ITC for difference waves in relation to DYS status and age band. Colours indicate range from zero (green) to 0.2 (deep red).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: ITC for difference waves in relation to DYS status and age band. Colours indicate range from zero (green) to 0.2 (deep red).
Mentions: Figures 4 and 5 show the mean levels of ITC, along with their spectral components, for mismatch waves in frequencies ranging from 1 to 20 Hz for the four subgroups. As described by Bishop et al. [23], the MMN region is characterized by a burst of increased ITC that is particularly marked in frequencies below 10 Hz. Visual inspection suggested that the DYS groups showed greater synchronization of these frequencies during the MMN time window relative to the controls. To explore this further, we compared the mean ITC in the first half of the trial (0–300 ms) between groups for the small and large deviants (see Table 2). Repeated measures ANCOVA revealed a significant three-way interaction between DYS status, age band, and deviant size, F(1, 35) = 4.61, p = 0.039. To explore this interaction, we first divided the sample into younger and older age bands. Repeated measures ANCOVA showed that for the older age band, the DYS group showed larger ITCs than the TD group, regardless of deviant size, F(1, 18) = 12.93, p = 0.002. However, for the younger age band, there was a significant interaction between DYS status and deviant size, F(1, 18) = 6.53, p = 0.020. Follow-up t tests showed that whereas there was no significant difference between the younger DYS and TD groups in the size of their ITC to the large deviant, t(1, 18) = 1.34, p = 0.198, the younger DYS group had a significantly larger ITC than the younger TD group in response to small deviants, t(1, 18) = -3.27, p = 0.004.

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