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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

ERSP for difference waves in relation to DYS status and age band. Colours indicate range from -0.75 (deep blue) through zero (green) to 0.75 (deep red).
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Figure 7: ERSP for difference waves in relation to DYS status and age band. Colours indicate range from -0.75 (deep blue) through zero (green) to 0.75 (deep red).

Mentions: Figures 6 and 7 show corresponding data for the ERSP. As demonstrated by Bishop et al. [48], the plots for the TD group were characterized by a decrease in power across a broad frequency band in the later half of the trial (blue denoting power below baseline levels). The DYS group, in contrast, showed what appeared to be a greater but less prolonged decrease in power that was restricted to frequencies below approximately 13 Hz. Repeated measures ANCOVA was used to compare the mean ERSP in the theta range (4–7 Hz) from 300–600 ms between the DYS and TD groups and between age bands (see Table 2). This demonstrated a significant interaction between group and age band, F(1, 35) = 11.55, p = 0.0023. We investigated this interaction by dividing the group into younger and older age bands and re-running the model. For the older age band, whereas the TD group showed a large decrease in power over the LDN time window, the DYS group did not, F(1, 18) = 8.45, p = 0.009. In contrast, the younger DYS group did not differ significantly in their amount of ERSP over the same time window, F(1, 18) = 2.49, p = 0.132.


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)

ERSP for difference waves in relation to DYS status and age band. Colours indicate range from -0.75 (deep blue) through zero (green) to 0.75 (deep red).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 7: ERSP for difference waves in relation to DYS status and age band. Colours indicate range from -0.75 (deep blue) through zero (green) to 0.75 (deep red).
Mentions: Figures 6 and 7 show corresponding data for the ERSP. As demonstrated by Bishop et al. [48], the plots for the TD group were characterized by a decrease in power across a broad frequency band in the later half of the trial (blue denoting power below baseline levels). The DYS group, in contrast, showed what appeared to be a greater but less prolonged decrease in power that was restricted to frequencies below approximately 13 Hz. Repeated measures ANCOVA was used to compare the mean ERSP in the theta range (4–7 Hz) from 300–600 ms between the DYS and TD groups and between age bands (see Table 2). This demonstrated a significant interaction between group and age band, F(1, 35) = 11.55, p = 0.0023. We investigated this interaction by dividing the group into younger and older age bands and re-running the model. For the older age band, whereas the TD group showed a large decrease in power over the LDN time window, the DYS group did not, F(1, 18) = 8.45, p = 0.009. In contrast, the younger DYS group did not differ significantly in their amount of ERSP over the same time window, F(1, 18) = 2.49, p = 0.132.

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