Materials related to the project on diagnosing BPPV through nystagmus recognition.
BPPV diagnosis
Below is a quick reference table for BPPV diagnosis based on the contents of the documents. Based on the nystagmus characteristics of the four tests left DP, right DP, left Roll Test (RT) and right Roll Test (RT), seven diagnostic outcomes (six BPPV subtypes + negative) can be clearly distinguished:
| Diagnosis | Left DP test | Right DP test | Left RT test (head turned to the left) | Right RT test (head turned to the right) | Key diagnostic criteria |
|---|---|---|---|---|---|
| Right posterior canal canalithiasis (RP ca) | Negative (no nystagmus) | Positive (counterclockwise nystagmus) | Negative (head-movement nystagmus not recorded) | Negative (head-movement nystagmus not recorded) | Right DP induces short-latency counterclockwise nystagmus (1-5 seconds); Epley treatment is effective |
| Right horizontal canal canalithiasis (RH ca) | Negative | Negative | Negative or weak geotropic nystagmus | Positive: strong geotropic nystagmus | Right RT induces strong geotropic nystagmus (fast phase toward the ground); the side with the stronger response is the affected side |
| Right horizontal canal cupulolithiasis (RH cu) | Negative or weak nystagmus | Negative or weak nystagmus | Positive: strong apogeotropic nystagmus | Positive: weak apogeotropic nystagmus | Left RT induces strong apogeotropic nystagmus (fast phase toward the healthy side); the side with the stronger response is the affected side |
| Left posterior canal canalithiasis (LP ca) | Positive (clockwise nystagmus) | Negative (no nystagmus) | Negative (head-movement nystagmus not recorded) | Negative (head-movement nystagmus not recorded) | Left DP induces short-latency clockwise nystagmus (1-5 seconds); Epley treatment is effective |
| Left horizontal canal canalithiasis (LH ca) | Negative | Negative | Positive: strong geotropic nystagmus | Negative or weak geotropic nystagmus | Left RT induces strong geotropic nystagmus (fast phase toward the affected side); the side with the stronger response is the affected side |
| Left horizontal canal cupulolithiasis (LH cu) | Negative or weak nystagmus | Negative or weak nystagmus | Positive: weak apogeotropic nystagmus | Positive: strong apogeotropic nystagmus | Right RT induces strong apogeotropic nystagmus (fast phase toward the healthy side); the side with the stronger response is the affected side |
| Positional tests negative (no BPPV) | Negative | Negative | Negative | Negative | No nystagmus in any test |
Usage notes
Determining the nystagmus direction (based on the viewing perspective of the left-eye recording):
- Clockwise: appears as clockwise rotation when observed from the patient’s left eye
- Counterclockwise: appears as counterclockwise rotation when observed from the patient’s left eye
- Geotropic: fast phase toward the ground (horizontal nystagmus)
- Apogeotropic: fast phase toward the sky (horizontal nystagmus)
Key rules:
- Posterior canal lesions: only the DP test is positive (the affected-side position induces vertical-torsional nystagmus); RT is always negative.
- Horizontal canal lesions: DP is always negative; RT distinguishes between:
- Canalithiasis (ca): RT toward the affected side induces strong geotropic nystagmus
- Cupulolithiasis (cu): RT toward the affected side induces strong apogeotropic nystagmus
- Locating the affected side: for the horizontal canal, the side with the strongest nystagmus in the RT test is the affected side.
Treatment hints:
- Posterior canal canalithiasis: the Epley repositioning maneuver is effective
- Horizontal canal lesions: the Barbecue or Gufoni repositioning maneuver is needed
Note: all tests must exclude the transient nystagmus during head movement (only the nystagmus after the head position has stabilized is recorded).
| Diagnosis | Left DP test | Right DP test | Left RT test (head turned to the left) | Right RT test (head turned to the right) | Key diagnostic criteria |
|---|---|---|---|---|---|
| Right posterior canal canalithiasis (RP ca) | No nystagmus | Counterclockwise | No nystagmus | No nystagmus | Right DP induces short-latency counterclockwise nystagmus (1-5 seconds); Epley treatment is effective |
| Right horizontal canal canalithiasis (RH ca) | No nystagmus | No nystagmus | No nystagmus or geotropic | Geotropic | Right RT induces geotropic nystagmus (fast phase toward the ground); the side with the stronger response is the affected side |
| Right horizontal canal cupulolithiasis (RH cu) | No nystagmus or weak nystagmus | No nystagmus or weak nystagmus | Apogeotropic | Apogeotropic | Left RT induces apogeotropic nystagmus (fast phase toward the healthy side); the side with the stronger response is the affected side |
| Left posterior canal canalithiasis (LP ca) | Clockwise | No nystagmus | No nystagmus | No nystagmus | Left DP induces short-latency clockwise nystagmus (1-5 seconds); Epley treatment is effective |
| Left horizontal canal canalithiasis (LH ca) | No nystagmus | No nystagmus | Geotropic | No nystagmus or geotropic | Left RT induces geotropic nystagmus (fast phase toward the affected side); the side with the stronger response is the affected side |
| Left horizontal canal cupulolithiasis (LH cu) | No nystagmus or weak nystagmus | No nystagmus or weak nystagmus | Apogeotropic | Apogeotropic | Right RT induces apogeotropic nystagmus (fast phase toward the healthy side); the side with the stronger response is the affected side |
| Positional tests negative (no BPPV) | No nystagmus | No nystagmus | No nystagmus | No nystagmus | No nystagmus in any test |
Classification task metrics
📊 Summary of common classification metrics
| Metric | Meaning | Formula | Focus |
|---|---|---|---|
| Precision | Of the samples judged positive, how many are truly positive | TP / (TP + FP) | Don’t wrongly accuse the innocent |
| Recall | The proportion of all true positives that are successfully identified | TP / (TP + FN) | Don’t let the guilty slip through |
| F1-score | The harmonic mean of precision and recall | 2 * (P * R) / (P + R) | Balance both |
| Accuracy | The proportion of all judgments that are correct | (TP + TN) / (TP + FP + FN + TN) | Whether the overall recognition is correct |
Where:
- TP: true positive (predicted positive, actually positive)
- FP: false positive (predicted positive, actually negative)
- FN: false negative (predicted negative, actually positive)
- TN: true negative (predicted negative, actually negative)
Lessons learned
Before starting a project, get the project requirements clear, and do broad research and gather materials; don’t just start writing code and training models on a whim…
Translated from the Chinese original.
