Dyslexia Reading EEG Research Reveals a Surprising Link Between Color and the Brain

Dyslexia reading EEG research has mostly focused on text processing and phonology. But what if the color of the page matters too?

A 2021 study published in Brain Sciences set out to answer that. It tested 36 school-age children – 18 with dyslexia and 18 typical readers. They read the same story across 13 different color conditions. Brain activity, skin conductance, heart rate, and eye movements were all captured at the same time. The result is one of the most detailed multi-sensor pictures of how color shifts the neurophysiology of reading.

Study setup and task

The setup was built around a portable sensor hub. It combined 4 physiological modalities in one recording session. EEG and ECG signals were recorded using mbt’s mobile EEG device. Electrodermal activity (EDA) came from a research-grade custom prototype. Eye movements were captured at 120 Hz using a remote eye tracker. All streams were synchronized via Lab Streaming Layer (LSL), and keyboard markers defined the start and end of each color slide.

Participants read a continuous story drawn from a Serbian third-grade textbook. It was divided into 13 self-paced paragraphs, one per color condition. The first slide always showed black text on white. This was the standard classroom reference. The remaining 12 color slides appeared in a pseudo-randomized order. Background colors were paired with black text.

The 13 conditions covered seven background colors: white (reference), red, blue, yellow, orange, purple, and turquoise. The overlay used the same six colors plus yellow. The colored-background design is relatively rare in dyslexia reading EEG work, making this one of the broadest color surveys.

The eye-movement signature of dyslexia holds across every color

Across all color conditions, children with dyslexia showed longer reading times, more fixations, and longer fixation durations. They also had higher saccade counts and longer saccade durations. Controls scored higher on fixation frequency and saccade frequency. Typical readers covered more fixation events per second. This fits what other dyslexia studies have established. Typical readers process a wider letter span per fixation.

These differences were stable across all 13 color conditions.

Turquoise helps. Purple does something else.

For dyslexic children, turquoise background produced the shortest reading times of any condition. Turquoise overlay came second. Yellow background ranked third. This confirmed earlier work identifying yellow as beneficial for dyslexic readers.

For typical readers, the pattern differed. Their shortest reading times came from violet overlay, blue overlay, and orange overlay. These weren’t the colors that helped dyslexic children.

The EEG data told a specific story about purple. During the purple background condition, children with dyslexia showed significantly elevated beta (15–40 Hz) power. Broadband (0.5–40 Hz) power was also elevated compared to controls. During the purple overlay, their theta band power was significantly increased.

Elevated beta and disrupted theta oscillations appear consistently in dyslexia reading EEG research. They’re among the most replicated neurophysiological markers of the disorder. Purple appears to selectively trigger that pattern.

EDA separates the groups most cleanly

Of all four modalities, EDA showed the most consistent between-group difference. It’s rarely included in dyslexia reading EEG protocols, but this study suggests it should be. Non-dyslexic children had higher EDA values across almost all color conditions. The exceptions are informative. Orange, turquoise overlay, and orange overlay are all lower-saturation conditions. Prior work shows that pastel colors have a calming effect on arousal. That effect appears across both groups here.

Heart rate follows color-specific patterns

HRV findings were more selective than EEG or EDA. In the dyslexia reading EEG literature, HRV tends to show the weakest between-group effects.

On white background, no significant group differences appeared for any HRV parameter. When specific colors were examined, some differences appeared. Non-dyslexic children showed higher mean heart rate on purple, turquoise overlay, and yellow overlay. Dyslexic children showed higher mean RR intervals in those same conditions.

Higher HR in controls and higher RR in the dyslexic group both suggest lower sympathetic arousal. This pattern appears under specific color conditions in dyslexic children and mirrors the EDA results.

A clearer picture of dyslexia

This study adds neurophysiological depth to a question that’s mostly been approached behaviorally. Turquoise background and overlay consistently produced the shortest reading times for dyslexic children. Purple triggered elevated beta and broadband power. This pattern is consistent with dyslexia reading EEG profiles in the broader literature

This dyslexia reading EEG research added eye-tracking, EDA, and HRV in a single portable session. That multimodal approach lays the groundwork for sensor-based tools to support earlier identification of dyslexia.

Read the original paper: Jakovljević et al. (2021)