Expanding our understanding of sensory gating in children with autism spectrum disorders

Abstract

Objective: This study examined sensory gating in children with autism spectrum disorders (ASD). Gating is usually examined at the P50 component and rarely at mid- and late-latency components.

Methods: Electroencephalography data were recorded during a paired-click paradigm, from 18 children with ASD (5-12 years), and 18 typically-developing (TD) children. Gating was assessed at the P50, N1, P2, and N2 event-related potential components. Parents of all participants completed the Short Sensory Profile (SSP).

Results: TD children showed gating at all components while children with ASD showed gating only at P2 and N2. Compared to TD children, the ASD group showed significantly reduced gating at P50, N1, and P2. No group differences were found at N2, suggesting typical N2 gating in the ASD group. Time-frequency analyses showed reduced orientation and neural synchronization of auditory stimuli. P50 and N1 gating significantly correlated with the SSP.

Conclusion: Although children with ASD have impaired early orientation and filtering of auditory stimuli, they exhibited gating at P2 and N2 components suggesting use of different gating mechanisms compared to TD children. Sensory deficits in ASD may relate to gating.

Significance: The data provide novel evidence for impaired neural orientation, filtering, and synchronization in children with ASD.

Keywords: Auditory filtering; Autism spectrum disorders; Electroencephalography (EEG); Sensory gating; Time-frequency analysis.

Figure 1:

Topographical map of the P50 component based on averaged event-related potentials of click 1 and click 2.

Figure 2:

Event-related potential plots for three typically-developing children (depicted in blue) on the left and three children with autism spectrum disorder (depicted in green) on the right. The averaged brain response to the first click stimuli is shown with a solid line, while the second click is shown as a dashed line. Data were filtered with a bandpass setting of .23 to 30 Hz. The three children in each group represent the 75^th, 50^th, and 25^th percentile of the respective group’s distribution (panel A, panel B, and panel C, respectively) of the Click 1 peak-to-peak N1 amplitudes. The N1 peak-to-peak amplitude was calculated as the difference in amplitude between the N1 peak and the preceding P1 peak.

Figure 3:

Grand averaged event-related potentials for each group (typically-developing children [TD] and children with autism spectrum disorder [ASD]) and each click (click 1 and click 2) time-locked to the auditory stimuli at the Cz electrode site

Figure 4:

Time-frequency plot of evoked power from the sensory gating paradigm. The white line at 0 milliseconds on the time axis indicates the onset of click 1, and the second white line at 500 milliseconds depicts the onset of click 2. A. Evoked power for typically-developing (TD) children. B. Evoked power for children with autism spectrum disorders (ASD). C. T map comparing the evoked power for the two groups.

Figure 5.

Time-frequency plot depicting phase-locking or inter-trial coherence during the sensory gating paradigm. The white line at 0 milliseconds on the time axis indicates the onset of click 1, and the second white line at 500 milliseconds depicts the onset of click 2. A. Phase-locking plot for typically-developing (TD) children. B. Phase-locking for children with autism spectrum disorders (ASD). C. T map comparing Phase-locking for the two groups.

Figure 6:

T map comparing evoked power between the two clicks. A. Comparison of clicks in typically-developing (TD) children. B. Comparison of clicks in children with autism spectrum disorders (ASD).