Syllabic Diadochokinesis in Adults With and Without Traumatic Brain Injury: Severity, Stability, and Speech Considerations
Bibliographic record
Abstract
Purpose Syllabic diadochokinesis (DDK) is a standard assessment task for motor speech disorders. This study aimed to compare rate and regularity of DDK according to the presence or absence of traumatic brain injury (TBI) and severity of TBI, examine the stability of DDK over time, and explore associations between DDK and extemporaneous speech. Method Military service members and veterans were categorized into three groups: no history of TBI (control), uncomplicated mild TBI (mTBI), and moderate through severe (including penetrating) TBI (msTBI). Participants produced rapid alternating-motion and sequential-motion syllable repetitions during one or two sessions. A semi-automated protocol determined syllabic rate and regularity. Perceptual ratings of selected participants' connected speech samples were compared to DDK results. Results Two hundred sixty-three service members and veterans provided data from one session and 69 from two sessions separated by 1.9 years ( SD = 1.0). DDKs were significantly slower overall for mTBI and msTBI groups compared to controls. Regularity of productions did not differ significantly across groups. A significant Group × Task interaction revealed that the msTBI group produced sequential-motion syllable repetitions but not alternating-motion repetitions with greater regularity, whereas the opposite occurred for control and mTBI groups. DDK results did not differ significantly between sessions. Perceptual speech analysis for 30 participants, including 20 with atypical or questionable DDK performance, revealed two participants with mildly abnormal speech. Conclusions Overall, DDK productions are slower than normal in adults with moderate, severe, and penetrating TBI and are stable over time. Regularity of productions did not differentiate groups, although this result differed according to task. There were surprisingly few people identified with disordered speech, making comparisons to DDK data tenuous, and indicating that dysarthria is a rare complication in a population of adults with mostly uncomplicated mTBI who are not selected from referrals to a speech-language pathology clinic.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".