Section 263 of 440
Complete canonical tutorial. This reader section contains the same teaching body as PWR-081 · Tactile acuity. Open the Power dossier.
PWR-081 · SELF GUIDED full tutorial
Compare safe surface details with one fingertip and a hidden answer key
Tactile acuity is the ability to tell small touch details apart at a named body site. This lesson uses coded, room-temperature surfaces rather than needles, monofilaments, two-point tools or pain. You will keep the finger and contact time fixed, make a forced same-or-different choice, reveal the answer only afterwards and test a new pair later.
1 · Permission and limits
Know exactly what you may do
2 · Get ready
Gather what you need and check the starting conditions
What you need
- Six 5 cm squares of familiar clean, dry, blunt material, mounted securely in three matched pairs.
- Opaque codes on the back, a separate answer key, a coin or random-number list and a record sheet.
- A table, chair, timer and optional screen that blocks sight without restricting the hand.
Before you start
- Check the chosen fingertip for intact skin, ordinary comfortable sensation and no new numbness or pain.
- Rub every panel with a cloth-covered finger first; remove anything loose, scratchy, allergenic or hard to clean.
- Choose one exploration rule: the pad of one finger, one left-to-right stroke and three seconds per panel.
3 · The method
Follow these steps in order
- Make coded pairs
Mount two samples from each of three safe material types. Give every panel a code that does not reveal its material, then write the true pairings on a separate key.
Why: Duplicate samples allow real same trials as well as different trials.
Check: The answer key lists three pairs and cannot be seen from the touching side.
- Fix the touch configuration
Name the fingertip, hand, stroke direction, pressure cue and three-second contact time. Use that same setup for every scored trial.
Why: Changing the site or movement changes what is being tested.
Check: You can demonstrate the same single stroke twice without rubbing, tapping or switching fingers.
- Create a balanced trial list
Prepare six same and six different pairings in a random order. Keep the list hidden until the response is made.
Why: A balanced, hidden order prevents guessing from a visible pattern.
Check: The list has 12 trials, equal same and different answers, with no answer exposed early.
- Touch and commit
Touch the first panel once, pause, touch the second once, then say same or different and give confidence from 0 to 100. Do not return for extra strokes.
Why: A committed response preserves a comparable amount of information on each trial.
Check: Each row has one choice and one confidence number before feedback.
- Reveal and name the cue
Check the key after each response. Mark correct or incorrect and write the cue you used, such as ridge spacing, softness or drag.
Why: Immediate, truthful feedback connects the cue with the result instead of rewarding confidence alone.
Check: The record shows the answer, correctness and a concrete touch cue.
- Retest without the old answers
After at least 48 hours, run eight new coded trials, including two safe material types not used in the first session. Keep the same finger and stroke rule.
Why: Delayed and unfamiliar trials separate repeated-board memory from limited near transfer.
Check: The retest records old-pair and new-material accuracy separately.
4 · Worked example
See the whole method used once
Scenario
A board contains duplicate squares of smooth cotton, ribbed card and soft felt, coded A1 to A6.
Walkthrough
- Mina writes the three true pairings on a folded key and makes a list with six same and six different trials.
- She uses the right index fingertip, one three-second left-to-right stroke per panel and no visual view.
- On A2 then A5 she answers different at 70% confidence because the second panel drags more.
- The key shows cotton then felt, so she marks correct and names drag as the cue.
- Two days later she scores old pairs separately from new linen-versus-foam pairs.
Result
Mina scores 9/12 initially, then 6/8 on the delayed set, including 1/2 on unfamiliar materials. That is performance for this fingertip, board and response rule; it is not a clinical threshold or whole-body gain.
5 · Right and wrong
Compare correct or safer execution with the common wrong version
| Moment | Right / safer | Wrong / riskier | Why it matters |
|---|---|---|---|
| Choosing stimuli | Use securely mounted, familiar, clean and comfortable room-temperature surfaces. | Use a pin, ice cube, heated object or mystery material to make differences stronger. | Clinical, thermal, chemical and painful stimuli add harm without improving this educational comparison. |
| Exploration | Use one declared fingertip and the same timed stroke. | Rub until certain or switch fingers on difficult trials. | Unequal exploration makes trial scores incomparable. |
| Feedback | Commit first, then reveal the coded answer. | Look at the material or answer key before deciding. | Previewing the answer measures memory and visual identification, not blind touch discrimination. |
| Claim | Report correct choices for this board and novel pair separately. | Call an improved score a lower tactile threshold or pain recovery. | This fixture is not a validated threshold or clinical outcome measure. |
6 · Common mistakes
Spot the error and apply the correction
| Mistake | Fix |
|---|---|
| The two copies in a same pair are not actually alike. | Cut duplicates from adjacent parts of one material and precheck them before coding. |
| Pressure increases when confidence falls. | Use the same light contact cue and stop after one stroke, even when uncertain. |
| The trial order has mostly different answers. | Build equal same and different trials before starting and randomise only their order. |
| Old-board memory is called transfer. | Add unfamiliar safe surfaces after a delay and score them in their own column. |
7 · Practice
Turn the steps into a usable skill
First session
- Inspect and code six panels.
- Complete two unscored demonstrations to learn the stroke rule.
- Run 12 balanced trials with feedback after each response.
- Count correct same and correct different responses separately and stop before skin irritation.
Repeat plan
Use one 8- to 12-trial session, two or three times in one week, with at least a day between sessions. On the last session replace one material pair. Do not increase pressure, temperature, sharpness or session length to create difficulty.
Progress when
- On a second matched set, same and different errors are stable or lower than on the learner’s first rule-consistent set; an uncertain small-sample result is labelled uncertain.
- The learner follows the single-stroke rule without extra exploration.
- Accuracy on at least one unfamiliar pair is recorded rather than assumed.
Do not progress when
- Skin becomes sore, numb, broken or unusually sensitive.
- Performance depends on seeing codes, repeated rubbing or memorised trial order.
- The goal becomes diagnosis, Braille instruction or treatment of pain or sensory loss.
8 · Check the result
Measure what changed
Balanced same-or-different accuracy at one declared fingertip.
How: Divide correct responses by total trials and also report same-trial accuracy, different-trial accuracy, median confidence and unfamiliar-pair accuracy.
Good result: A useful learning result is a rule-consistent record that separates same and different errors and shows whether the unfamiliar-pair result is reproduced on a second matched set. No fixed count is a clinical pass.
This does not prove: It does not prove receptor change, clinical normality, pain improvement, Braille skill or transfer to another body site.
Self-check
- Can you name the exact finger, movement and contact time used?
- Were equal same and different trials hidden until after each answer?
- Can you point to a separate score for unfamiliar materials?
- Can you explain why this is not a clinical tactile threshold?
9 · Stop, adapt or get help
Keep the safety boundary practical
Stop and get help
- Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
- Discard and clean the set if a surface becomes damp, dirty, loose or contaminated.
- Seek appropriate clinical advice for new, one-sided, spreading or function-changing sensory loss instead of repeating the test.
Accessibility and adaptations
- Use larger panels and a hand guide while preserving the single declared contact path.
- A helper may randomise and record spoken answers without cueing them.
- Use the most comfortable intact hand or body site and treat any site change as a new baseline, not a failure.
10 · Evidence and limits
Why these instructions are here
- primary research
Training gains in tactile spatial acuity approached a limit related to fingertip size and transferred less to an untrained finger.
A physical constraint on perceptual learning: tactile spatial acuity improves with training to a limit set by finger size - primary research
A pilot clinical trial did not show superiority to sham and reported worse pain in the intervention group, so this lesson makes no pain-treatment claim.
Tactile acuity training for patients with chronic low back pain: a pilot randomised controlled trial
Limits
- Scores belong to the named fingertip, materials and exploration rule.
- Safe surface comparison is not two-point discrimination, grating threshold testing or diagnosis.
- Improvement on repeated panels may be item learning and must not be called universal tactile enhancement.
Open the complete canonical research register
- Primary empirical supportLimiting / contraryTactile discrimination, but not tactile stimulation alone, reduces chronic limb pain
G. L. Moseley; N. M. Zalucki; K. Wiech · 2008 · Primary research
- Primary empirical supportLimiting / contraryTactile acuity training for patients with chronic low back pain: a pilot randomised controlled trial
C. Ryan; N. Harland; B. T. Drew; D. Martin · 2014 · Primary research
- Primary empirical supportLimiting / contraryA physical constraint on perceptual learning: tactile spatial acuity improves with training to a limit set by finger size
M. Wong; R. M. Peters; D. Goldreich · 2013 · Primary research
- Primary empirical supportLimiting / contraryMassive cortical reorganization in sighted Braille readers
K. Siuda-Krzywicka; Ł. Bola; M. Paplińska; E. Sumera; K. Jednoróg; A. Marchewka; M. W. Śliwińska; A. Amedi; M. Szwed · 2016 · Primary research
Read the complete evidence interpretation on the Power dossier.
Tutorial delivery controls
Learn, adapt, troubleshoot and resume
Progress is saved only in this browser on this device.
Step-by-step learner mode
Each activity includes its success check, a nearby accessible alternative and an “I’m stuck” correction path. Alternatives preserve the target where possible; when they change the task, Titan labels them as related rather than equivalent.
Make coded pairs
Mount two samples from each of three safe material types. Give every panel a code that does not reveal its material, then write the true pairings on a separate key.
Duplicate samples allow real same trials as well as different trials.
The answer key lists three pairs and cannot be seen from the touching side.
I’m stuck on this step
Reset: Re-read this authored instruction — “Mount two samples from each of three safe material types. Give every panel a code that does not reveal its material, then write the true pairings on a separate key.” — and its success check, then attempt only this step.
Possible snag: The two copies in a same pair are not actually alike.
Correction: Cut duplicates from adjacent parts of one material and precheck them before coding.
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Fix the touch configuration
Name the fingertip, hand, stroke direction, pressure cue and three-second contact time. Use that same setup for every scored trial.
Changing the site or movement changes what is being tested.
You can demonstrate the same single stroke twice without rubbing, tapping or switching fingers.
I’m stuck on this step
Reset: Re-read this authored instruction — “Name the fingertip, hand, stroke direction, pressure cue and three-second contact time. Use that same setup for every scored trial.” — and its success check, then attempt only this step.
Possible snag: Pressure increases when confidence falls.
Correction: Use the same light contact cue and stop after one stroke, even when uncertain.
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Create a balanced trial list
Prepare six same and six different pairings in a random order. Keep the list hidden until the response is made.
A balanced, hidden order prevents guessing from a visible pattern.
The list has 12 trials, equal same and different answers, with no answer exposed early.
I’m stuck on this step
Reset: Re-read this authored instruction — “Prepare six same and six different pairings in a random order. Keep the list hidden until the response is made.” — and its success check, then attempt only this step.
Possible snag: The trial order has mostly different answers.
Correction: Build equal same and different trials before starting and randomise only their order.
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Touch and commit
Touch the first panel once, pause, touch the second once, then say same or different and give confidence from 0 to 100. Do not return for extra strokes.
A committed response preserves a comparable amount of information on each trial.
Each row has one choice and one confidence number before feedback.
I’m stuck on this step
Reset: Re-read this authored instruction — “Touch the first panel once, pause, touch the second once, then say same or different and give confidence from 0 to 100. Do not return for extra strokes.” — and its success check, then attempt only this step.
Possible snag: The result from “Touch the first panel once, pause, touch the second once, then say same or different and give confidence from 0 to 100. Do not return for extra strokes.” does not yet meet this declared check: Each row has one choice and one confidence number before feedback.
Correction: Return to the start of “Touch and commit”, reduce complexity or pace, and repeat only the part needed to satisfy: “Each row has one choice and one confidence number before feedback.”
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Reveal and name the cue
Check the key after each response. Mark correct or incorrect and write the cue you used, such as ridge spacing, softness or drag.
Immediate, truthful feedback connects the cue with the result instead of rewarding confidence alone.
The record shows the answer, correctness and a concrete touch cue.
I’m stuck on this step
Reset: Re-read this authored instruction — “Check the key after each response. Mark correct or incorrect and write the cue you used, such as ridge spacing, softness or drag.” — and its success check, then attempt only this step.
Possible snag: The result from “Check the key after each response. Mark correct or incorrect and write the cue you used, such as ridge spacing, softness or drag.” does not yet meet this declared check: The record shows the answer, correctness and a concrete touch cue.
Correction: Return to the start of “Reveal and name the cue”, reduce complexity or pace, and repeat only the part needed to satisfy: “The record shows the answer, correctness and a concrete touch cue.”
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Retest without the old answers
After at least 48 hours, run eight new coded trials, including two safe material types not used in the first session. Keep the same finger and stroke rule.
Delayed and unfamiliar trials separate repeated-board memory from limited near transfer.
The retest records old-pair and new-material accuracy separately.
I’m stuck on this step
Reset: Re-read this authored instruction — “After at least 48 hours, run eight new coded trials, including two safe material types not used in the first session. Keep the same finger and stroke rule.” — and its success check, then attempt only this step.
Possible snag: Old-board memory is called transfer.
Correction: Add unfamiliar safe surfaces after a delay and score them in their own column.
Stop / get help: Stop for pain, burning, persistent tingling, new numbness, colour change, swelling or broken skin.
Correct versus incorrect execution
These accessible process diagrams are built from the tutorial’s own right/wrong teaching. They are not anatomical illustrations and do not add technique beyond the canonical tutorial.
Use securely mounted, familiar, clean and comfortable room-temperature surfaces.
Use a pin, ice cube, heated object or mystery material to make differences stronger.
Use one declared fingertip and the same timed stroke.
Rub until certain or switch fingers on difficult trials.
Commit first, then reveal the coded answer.
Look at the material or answer key before deciding.
Report correct choices for this board and novel pair separately.
Call an improved score a lower tactile threshold or pain recovery.
Method-structure checklist
10 of 10 structural checks present
- Ordered, Power-specific instructions — present
- Every activity has a success check — present
- Materials or supplied records are declared — present
- Measurement or assessment rule is present — present
- Tutorial-specific troubleshooting is present — present
- Stopping or escalation boundary is present — present
- Every activity has an adjacent alternative — present
- Correct-versus-incorrect comparison is present — present
- Evidence context is bound to the Power record — present
- Planning metadata is present — present
The method-readiness band and presence checklist assess tutorial presentation and are separate from evidence quality for the underlying Power. They are automated editorial aids, not human approval.
Manual editorial sign-off: Pending. This tutorial must not display a human-approved state until an identified editor signs the exact content hash.