Electrocortical Dynamics in Children with a Language-Learning Impairment Before and After Audiovisual Training

Resting-state EEG alpha rhythm spectral power in children with specific language impairment: a cross-sectional study

PURPOSE

This study investigated EEG alpha rhythm spectral power in children with Specific Language Impairment (SLI) and compared it to typically developing children to better understand the electrophysiological characteristics of this disorder. Specifically, we explored resting-state EEG, because there are studies that point to it being linked to speech and language development.

METHODS

EEG recordings of 30 children diagnosed with specific language impairment and 30 typically developing children, aged 4.0-6.11 years, were carried out under eyes closed and eyes open conditions. Differences in alpha rhythm spectral power in relation to brain topography and experimental conditions were calculated.

RESULTS

In the eyes closed condition, alpha rhythm spectral power was statistically significantly lower in children with specific language impairment in the left temporal (T5) and occipital electrodes (O1, O2) than in typically developing children. In the eyes open condition, children with SLI showed significantly lower alpha rhythm spectral power in the left temporal (T3, T5), parietal (P3, Pz), and occipital electrodes (O1, O2). There were no statistically significant differences between the groups in relation to the relative change (the difference between average alpha rhythm spectral power during eyes closed condition and average alpha rhythm spectral power during eyes open condition divided by average alpha rhythm spectral power during eyes closed condition) in the alpha rhythm spectral power between the conditions.

CONCLUSION

Lower alpha rhythm spectral power in the left temporal, left, midline parietal, and occipital brain regions could be a valuable electrophysiological marker in children with SLI. Further investigation is needed to examine the connection between EEG alpha spectral power and general processing and memory deficits in patients with SLI.

Training-Induced Changes in Rapid Auditory Processing in Children With Specific Language Impairment: Electrophysiological Indicators

The brain’s ability to recognize acoustic changes occurring in rapid temporal succession is important for speech and successful language development. Children with specific language impairment (SLI) are characterized by deficient dynamics of temporal information processing (TIP) in the millisecond time range accompanied by disordered language development. Furthermore, previous studies have found that intervention based on amelioration of TIP resulted in improvement of both language and other cognitive functions. This study aimed to explain the changes associated with TIP training from the perspective of event-related potentials (ERPs). Thirty-six children aged 5–8 years (26 boys, 10 girls) diagnosed with SLI underwent two types of intense audio-visual computer intervention: experimental TIP training targeted at the millisecond time range (n = 18) or control non-TIP training (n = 18). Paired 50 ms tones of 1000 Hz and 1200 Hz were presented with inter-stimulus intervals (ISIs) of either 50 ms (Short ISI Condition) or 200 ms (Long ISI Condition). Auditory ERPs were measured in a passive oddball paradigm before and after each type of training. The mismatch negativity (MMN) paradigm was applied as an electrophysiological indicator of the brain’s ability to automatically detect violations of regularity in paired tones presented in rapid succession. Moreover, the P3a component was also analyzed. After 24 sessions of temporal training (in the experimental group) MMN amplitude enhancement was observed in both ISI conditions, reflecting increased efficiency in perceiving changes in rapid auditory sequences. In both experimental and control groups, P3a amplitude was enhanced in both ISIs. This may be due to the improvement of involuntary attention shifting to the auditory events involved in each training type. To conclude, temporal training, compared to non-temporal control training, improved the ability to detect changes in a rapid auditory stream in children with SLI.

Complex mismatch negativity to tone pair deviants in long-term schizophrenia and in the first-episode schizophrenia spectrum

Mismatch negativity (MMN) is an event-related potential to stimulus change. MMN to infrequent deviant tones that differs in a simple physical parameter from repetitive standard tones is reduced in patients with long-term schizophrenia (Sz; d=~1). However, this simple MMN is not uniformly reduced at the first-episode of schizophrenia-spectrum psychosis (FESz; d<0.1 for pitch; <0.4 for duration). Deviant stimuli that violate pattern rules also evoke MMN. This complex MMN is evoked by deviations in the relation of sounds to each other. The simplest pattern involves tone pairs. Although the pitch of first tone in the pair varies, the second tone's pitch always follows a rule (e.g., always 3 semitones higher). We measured complex MMN to deviant tone pairs that descended in pitch among standard tone pairs that ascended in pitch, never before examined in Sz or in FESz. Experiment 1 showed significant reductions in complex MMN in 20 Sz compared to 22 matched controls. Experiment 2 replicated smaller complex MMN in a shorter protocol in 24 Sz compared to 21 matched controls, but showed no significant complex MMN reduction in 21 FESz compared to 21 matched controls. Although reduced in Sz, indicating deficits in generation of a simple acoustic pattern rule, the tone pair complex MMN was within normal limits in FESz. This suggests that more complex perceptual pattern analysis processes are, at least partially, still intact at the first break. Future work will determine at what point of pattern complexity subtle auditory perception pathophysiology will be revealed in FESz.