Short answer: up to roughly 350 words per minute, no. Past that, yes, and it is measurable. The longer answer is more useful, because what you lose first is not what most people expect.
When comprehension is tested at 250, 300 and 350 words per minute with single-word presentation, it is not meaningfully different from normal reading. At 400 and 450 it drops. Above 500, comprehension degrades for everyone, and more sharply for readers working in a second language.
So the honest framing is not “speed reading destroys comprehension”. It is: there is a range where the trade is free, and a point past which you are paying.
This is the part that gets missed. As speed rises, the first thing to degrade is not literal recall — it is inferential comprehension. You can still answer what happened. What you lose is why it happened, what it implies, and how it connects to the paragraph before.
That has a practical consequence. If you test yourself on a fast read by asking “what was that about”, you will conclude you understood it. The check that catches the loss is asking something the text did not state directly.
A common argument for single-word reading is that removing eye movement removes fatigue. One study of a widely used implementation found the opposite: comprehension fell and visual fatigue rose. The proposed reason is blink rate — people blink less when their eyes stop moving, and dry eyes are a large part of what reading fatigue is.
This is why a reader that never suggests a break is not doing you a favour.
When presentation formats are compared directly, showing more of the text at once wins on comprehension. A moving highlight over normal paragraphs beat multi-line, which beat single-line, which beat one word at a time. Guided reading — the highlight, not the flashing word — measurably improved comprehension.
If your goal is understanding difficult material, that is the format the evidence favours. RSVP’s advantage is elsewhere: it is very hard to lose your place, because there is only one place.
Punctum applies those defaults out of the box, including a different starting speed for each language — the per-language numbers are in how fast can you actually read. More on the mechanism in what RSVP reading actually does.