As an alternative to theories positing visual or phonological deficits it has been suggested that the aetiology of dyslexia takes the form of a temporal processing deficit that may refer to impairment in the functional connectivity of the processes involved in reading. Here we investigated this idea in an experimental task designed to measure simultaneity thresholds. Fifteen children diagnosed with developmental dyslexia, alongside a matched sample of 13 normal readers undertook a series of threshold determination procedures designed to locate visual simultaneity thresholds and to assess the influence of subthreshold synchrony or asynchrony upon these thresholds. While there were no significant differences in simultaneity thresholds between dyslexic and normal readers, indicating no evidence of an altered perception, or temporal quantization of events, the dyslexic readers reported simultaneity significantly less frequently than normal readers, with the reduction largely attributable presentation of a subthreshold asynchrony. The results are discussed in terms of a whole systems approach to maintaining information processing integrity.