What Is Temporal Summation — and Why Can Repeated Touch Become Increasingly Painful?

When the Same Stimulus Feels Worse Each Time

Temporal summation describes a phenomenon in which an identical, repeated low-frequency painful stimulus is perceived as progressively more intense with each repetition, even though the physical stimulus itself has not changed at all.

A Build-Up of Spinal Cord Excitability

At the spinal cord level, repeated C-fibre nociceptive input can progressively increase the excitability of dorsal horn neurons — a phenomenon originally described in animal studies as "wind-up" — causing each successive signal to produce a disproportionately larger response in the spinal cord, and ultimately a disproportionately larger perceived pain (Price et al., 2002).

Why This Is Tested in Chronic Pain Research

Enhanced temporal summation has been documented in several chronic pain conditions, including fibromyalgia, and is considered one quantifiable marker of altered central pain processing. Clinically, it offers one explanation for why some people experience escalating discomfort from a repetitive, seemingly low-level stimulus — such as sustained typing or repeated light massage strokes — that would not trouble most people at all.