Measuring Lingual Range of Motion

For years, we’ve been hyper-focused on lingual strength—squeezing bulbs, pressing tongues against the palate, and tracking numbers on devices like the IOPI. But let’s not forget the other key player: lingual range of motion.

Measuring the Muscles of the Tongue: More Than Just Strength

We’ve had tools like the Iowa Oral Performance Instrument (IOPI) and Tongue Press to quantify strength. They’ve become standard in clinics for giving us that sweet, sweet data—numbers we can chart, track, and brag about in our documentation.

But what about range of motion?

That tongue needs to reach, stretch, elevate, and lateralize—not just press hard. Without range, all the strength in the world won’t get that bolus where it needs to go.

The Research We’ve Been Waiting For

We finally have a validated way to measure lingual range of motion, thanks to:

Lazarus, C.L., et al. (2014).
Development of a New Lingual Range-of-Motion Assessment Scale, Normative Data in Surgically Treated Oral Cancer Patients. Dysphagia, 29(4), 489–499.

This study compared:

36 patients post-oral tongue surgery
31 healthy individuals

Their goal? To create a standardized scale for lingual range-of-motion, correlate it with real-life outcomes, and give us a tool that tracks progress over time—hello, documentation goals!

The Lingual Range-of-Motion Scale

The study broke lingual movement into four domains:

Protrusion
Right Lateralization
Left Lateralization
Elevation

Each domain was scored out of 100 and then averaged for a total score ranging from 0 to 100.

Protrusion

Measured using a Therabite jaw ROM disc (because rulers in the mouth are just awkward).

100 (Normal): ≥15 mm past upper lip
50 (Mild-Moderate): >1 mm but <15 mm
25 (Severe): Some movement, can’t reach lip
0 (Total): No movement

Lateralization (Right & Left)

Assessed by the ability to touch the corner of the mouth (commissures).

100 (Normal): Full contact
50 (Mild-Moderate): 50% reduction
25 (Severe): >50% reduction
0 (Total): No movement

Elevation

Tongue tip toward the upper alveolar ridge.

100 (Normal): Full contact
50 (Moderate): Elevates but doesn’t reach
0 (Severe): No visible elevation

Total Score Interpretation:

Each of the 4 movements is scored and then averaged:

100 = Normal
50 = Mild to Moderate Impairment
25 = Severe Impairment
0 = Total Impairment

Additional Measures in the Study

The researchers didn’t stop at range-of-motion—they went all in:

Strength: Measured using the IOPI
Jaw ROM: Also measured using Therabite discs
Saliva Flow: Saxon test (chew a 4×4 gauze for 2 minutes—yum)
Function:
- Performance Status Scale: Diet, speech intelligibility, social eating
- Quality of Life: EAT-10, MDADI, SHI

So What Did They Find?

Lingual range-of-motion significantly impacts:

Diet and nutrition
Speech clarity
Social participation
Overall quality of life

And perhaps most importantly—it gives us another evidence-based tool to support our evaluations, treatment planning, and goal writing.

Final Thoughts

This validated scale lets us objectively measure lingual range of motion, which can support our clinical judgment and show progress over time. Especially for patients post oral surgery, this can guide treatment and help determine realistic functional outcomes.

We need to stop thinking only in strength and start thinking also about range of motion. After all, a strong tongue that can’t move where it needs to go isn’t doing anyone any good.

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