SUD and VOC Scales in EMDR, Explained

Two short numbers do a lot of work in an EMDR session: the SUD rating that tells you how disturbing a memory feels right now, and the VOC rating that tells you how true a positive belief feels. You use both constantly, but it's worth being precise about what they actually measure, where they came from, and where their limits are — especially when a screen is your only window into a client's state.

What SUD measures

SUD stands for Subjective Units of Disturbance (sometimes “Distress”). It’s a 0-to-10 self-report scale, with 0 meaning no disturbance or a neutral state and 10 meaning the highest disturbance the client can imagine. The scale was originally developed by psychologist Joseph Wolpe in 1969 as a self-report tool for exposure-based work, well before EMDR existed, and it’s since become a standard measure across cognitive-behavioral and trauma therapies generally, not just EMDR (Wikipedia, Subjective units of distress scale).

The prompt is simple and worth using consistently: “On a scale of zero to ten, where zero is no disturbance and ten is the highest disturbance you can imagine, how disturbing does this feel right now?” That “right now” matters — SUD tracks present-moment distress, not a memory of how bad it felt at its worst.

What VOC measures

VOC stands for Validity of Cognition. It’s a 1-to-7 scale that asks how true a positive belief about the self feels when paired with the target memory — 1 meaning it feels completely false, 7 meaning it feels completely true (Trauma Therapist Institute, practical guide to SUDs and VOC in EMDR). Unlike SUD, which you want to see fall, VOC is a scale you want to see rise — the goal is a felt sense of truth, not just an intellectual agreement that a positive belief is logically correct.

The gap between “I know it’s true” and “I believe it” is the whole point of tracking VOC separately from SUD. A client can rationally agree that “I did the best I could” is accurate while still feeling it at a 2 — and that gap is often exactly what reprocessing is working on.

Where they fit across the eight phases

Both scales show up at specific, predictable points in the standard protocol:

• Phase 3, Assessment: you establish baseline SUD and VOC for the target memory and the desired positive cognition, before any bilateral stimulation begins.
• Phase 4, Desensitization: SUD is checked after each set, tracking the memory’s emotional charge as it (ideally) comes down toward 0 or 1.
• Phase 5, Installation: once SUD has settled, attention shifts to VOC, strengthening the positive cognition toward a 7.
• Phase 8, Reevaluation: at the start of a later session, you recheck both ratings on the original target to confirm the shift held (Trauma Therapist Institute).

For the fuller structure these phases sit inside, our walkthrough of the eight phases of EMDR covers how each phase connects to the next, with notes on running the sequence remotely.

Eliciting honest ratings over a screen

A number given quickly to move things along isn’t the same as a number a client has actually checked in on. A few habits help get a more reliable read, especially when you can’t lean on the fuller range of in-person cues:

• Ask the same way every time. Consistent phrasing (“zero to ten, right now”) reduces the chance a client is answering a slightly different question each time you ask.
• Leave a beat of silence after asking, rather than filling it — a genuine check-in takes a second or two longer than a reflexive answer.
• Watch for a mismatch between the number and what you’re seeing or hearing. A flat “it’s a 3” delivered with a shaking voice is worth a gentle follow-up rather than taking the number at face value.
• Normalize “I don’t know” or in-between answers. Clients sometimes round to familiar numbers out of habit; permission to say “somewhere around a 6, maybe” often gets you a more honest read than a forced integer.

If a client’s ratings stall and won’t move across several sets, that’s usually a signal worth acting on rather than pushing through — our piece on what to do when EMDR processing gets stuck walks through a ladder of options, and the window of tolerance is often the underlying reason ratings freeze in the first place.

These scales aren’t limited to standard trauma targets, either. In phobia work, for example, SUD is often what you’re tracking most closely set to set, since the fear response itself is the presenting complaint — our piece on EMDR for panic disorder and specific phobias shows how that plays out with an anxiety-focused target.

A caution worth knowing about SUD specifically

SUD’s simplicity is also its weak point. A recent methodological review argues the scale is often poorly defined in practice — it’s not always clear whether a rating reflects anxiety specifically, general distress, or something else the client is folding in, and whether “right now” means current-moment or peak-remembered distress can vary session to session, which makes ratings harder to compare over time (Rethinking the Subjective Units of Distress Scale, PMC). The review’s practical suggestion is to supplement the number with a brief check on what the client means by it — “what’s the 6 made of right now?” — rather than treating the digit alone as a complete picture. That doesn’t make SUD less useful day to day; it’s a reminder to keep it paired with what you’re observing, not read in isolation.

Where CloudEMDR fits in

Nothing about SUD and VOC ratings changes because of the delivery tool, but a clean, distraction-free session makes it easier to actually pause and ask. With a CloudEMDR Pro Remote Session, your client sees only the moving dot — no visible controls, nothing competing for attention — while you keep a timer and the full session view on your side, which leaves room to build a genuine SUD or VOC check into the natural pause between sets rather than rushing it.