# Neck Disability Index NDI Status: LIVE Price: $0.005 USDC `GET /api/calc/ndi` HTML: https://magentlab.com/docs/ndi Markdown: https://magentlab.com/docs/ndi.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Sum ten caller-assigned Vernon 1991 Neck Disability Index sections (each integer 0-5) and return the published 0-50 total with that paper's raw-score disability bands. ## When to use When an agent already has Vernon 1991 integers 0-5 for the ten NDI sections and needs the published total and raw 0-50 bands. magent does not interview the patient, diagnose neck disease, score Oswestry, or apply later percentage website cutoffs. ## When not to use - Not a medical device and not a diagnosis of neck pathology or a treatment order. - Each of the ten sections is a caller-assigned integer 0-5. magent does not interview the patient. - Vernon 1991 scored the raw 0-50 total. Bands are 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, and >34 complete. magent does not convert to a 0-100 percent or apply later 0-8%/10-28% website percentage bands. - This is Vernon 1991 NDI only. magent does not score the Oswestry Low Back Pain Disability Questionnaire. ## Formula ``` NDI = pain_intensity + personal_care + lifting + reading + headaches + concentration + work + driving + sleeping + recreation; each caller-assigned 0-5; Vernon 1991 ten sections; max 50; raw 0-50 bands 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, >34 complete ``` ## Citation [The Neck Disability Index: a study of reliability and validity](https://pubmed.ncbi.nlm.nih.gov/1834753) Vernon H, Mior S J Manipulative Physiol Ther. 1991;14(7):409-415 DOI: none ## Worked example ### All items 0 Given: `concentration=0, driving=0, headaches=0, lifting=0, pain_intensity=0, personal_care=0, reading=0, recreation=0, sleeping=0, work=0` 1. pain_intensity, personal_care, lifting, reading, headaches, concentration, work, driving, sleeping, and recreation are 0 as assigned by the caller 2. Score = 0 (max 50); disability none (Vernon 1991 raw 0-4) ### All items 5 Given: `concentration=5, driving=5, headaches=5, lifting=5, pain_intensity=5, personal_care=5, reading=5, recreation=5, sleeping=5, work=5` 1. each of the ten Vernon 1991 sections is 5 as assigned by the caller 2. Score = 50 (max 50); disability complete (Vernon 1991 raw >34) ## Also searched as - NDI - Neck Disability Index - Vernon NDI - neck pain disability - NDI score - Vernon 1991 NDI - cervical disability index - neck disability questionnaire - NDI 0-50 ## Parameters - `pain_intensity` (integer, required): Caller-assigned Vernon 1991 NDI pain intensity (integer 0-5): 0 no pain at the moment through 5 worst imaginable pain at the moment. magent does not interview the patient. - `personal_care` (integer, required): Caller-assigned Vernon 1991 NDI personal care (washing, dressing) (integer 0-5): 0 looks after self normally without extra pain through 5 does not get dressed, washes with difficulty and stays in bed. magent does not interview the patient. - `lifting` (integer, required): Caller-assigned Vernon 1991 NDI lifting (integer 0-5): 0 can lift heavy weights without extra pain through 5 cannot lift or carry anything. magent does not interview the patient. - `reading` (integer, required): Caller-assigned Vernon 1991 NDI reading (integer 0-5): 0 can read as much as wanted with no neck pain through 5 cannot read at all. magent does not interview the patient. - `headaches` (integer, required): Caller-assigned Vernon 1991 NDI headaches (integer 0-5): 0 no headaches through 5 headaches almost all the time. magent does not interview the patient. - `concentration` (integer, required): Caller-assigned Vernon 1991 NDI concentration (integer 0-5): 0 can concentrate fully with no difficulty through 5 cannot concentrate at all. magent does not interview the patient. - `work` (integer, required): Caller-assigned Vernon 1991 NDI work (integer 0-5): 0 can do as much work as wanted through 5 cannot do any work at all. magent does not interview the patient. - `driving` (integer, required): Caller-assigned Vernon 1991 NDI driving (integer 0-5): 0 can drive without neck pain through 5 cannot drive at all. magent does not interview the patient. - `sleeping` (integer, required): Caller-assigned Vernon 1991 NDI sleeping (integer 0-5): 0 no trouble sleeping through 5 sleep completely disturbed (5-7 hours sleepless). magent does not interview the patient. - `recreation` (integer, required): Caller-assigned Vernon 1991 NDI recreation (integer 0-5): 0 can engage in all recreation activities with no neck pain through 5 cannot do any recreation activities. magent does not interview the patient. ## Bulk (POST) POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/ndi` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows. - The first invalid item fails the whole request (index in the 400 JSON). You are not charged. - HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row. - Catalog misses (empty matches, found=false) stay paid 200s inside that slot. - x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items. Example request: ```json { "items": [ { "concentration": "0", "driving": "0", "headaches": "0", "lifting": "0", "pain_intensity": "0", "personal_care": "0", "reading": "0", "recreation": "0", "sleeping": "0", "work": "0" }, { "concentration": "0", "driving": "0", "headaches": "0", "lifting": "0", "pain_intensity": "0", "personal_care": "0", "reading": "0", "recreation": "0", "sleeping": "0", "work": "0" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/ndi Example 200: ```json { "count": 2, "path": "/api/calc/ndi", "items": [ { "components": [ { "value": 0, "factor": "pain_intensity", "points": 0, "present": true }, { "value": 0, "factor": "personal_care", "points": 0, "present": true }, { "value": 0, "factor": "lifting", "points": 0, "present": true }, { "value": 0, "factor": "reading", "points": 0, "present": true }, { "value": 0, "factor": "headaches", "points": 0, "present": true }, { "value": 0, "factor": "concentration", "points": 0, "present": true }, { "value": 0, "factor": "work", "points": 0, "present": true }, { "value": 0, "factor": "driving", "points": 0, "present": true }, { "value": 0, "factor": "sleeping", "points": 0, "present": true }, { "value": 0, "factor": "recreation", "points": 0, "present": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Vernon H, Mior S", "id": "vernon-1991", "pmid": "1834753", "source": "J Manipulative Physiol Ther. 1991;14(7):409-415", "title": "The Neck Disability Index: a study of reliability and validity" }, "formula": "ndi", "formula_expression": "NDI = pain_intensity + personal_care + lifting + reading + headaches + concentration + work + driving + sleeping + recreation; each caller-assigned 0-5; Vernon 1991 ten sections; max 50; raw 0-50 bands 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, >34 complete", "max_score": 50, "score": 0, "disability": "none" }, { "components": [ { "value": 0, "factor": "pain_intensity", "points": 0, "present": true }, { "value": 0, "factor": "personal_care", "points": 0, "present": true }, { "value": 0, "factor": "lifting", "points": 0, "present": true }, { "value": 0, "factor": "reading", "points": 0, "present": true }, { "value": 0, "factor": "headaches", "points": 0, "present": true }, { "value": 0, "factor": "concentration", "points": 0, "present": true }, { "value": 0, "factor": "work", "points": 0, "present": true }, { "value": 0, "factor": "driving", "points": 0, "present": true }, { "value": 0, "factor": "sleeping", "points": 0, "present": true }, { "value": 0, "factor": "recreation", "points": 0, "present": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Vernon H, Mior S", "id": "vernon-1991", "pmid": "1834753", "source": "J Manipulative Physiol Ther. 1991;14(7):409-415", "title": "The Neck Disability Index: a study of reliability and validity" }, "formula": "ndi", "formula_expression": "NDI = pain_intensity + personal_care + lifting + reading + headaches + concentration + work + driving + sleeping + recreation; each caller-assigned 0-5; Vernon 1991 ten sections; max 50; raw 0-50 bands 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, >34 complete", "max_score": 50, "score": 0, "disability": "none" } ] } ``` ## Response fields - `formula` (string): ndi - `formula_expression` (string): Exact expression used - `score` (integer): Vernon 1991 sum of ten caller-assigned 0-5 sections (total 0-50) - `max_score` (integer): Always 50 - `disability` (string): Vernon 1991 raw 0-50 bands: none (0-4), mild (5-14), moderate (15-24), severe (25-34), complete (>34). Not a diagnosis. - `components` (array): Per-section caller-assigned points - `citation` (object): Vernon and Mior J Manipulative Physiol Ther 1991 citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "value": 0, "factor": "pain_intensity", "points": 0, "present": true }, { "value": 0, "factor": "personal_care", "points": 0, "present": true }, { "value": 0, "factor": "lifting", "points": 0, "present": true }, { "value": 0, "factor": "reading", "points": 0, "present": true }, { "value": 0, "factor": "headaches", "points": 0, "present": true }, { "value": 0, "factor": "concentration", "points": 0, "present": true }, { "value": 0, "factor": "work", "points": 0, "present": true }, { "value": 0, "factor": "driving", "points": 0, "present": true }, { "value": 0, "factor": "sleeping", "points": 0, "present": true }, { "value": 0, "factor": "recreation", "points": 0, "present": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Vernon H, Mior S", "id": "vernon-1991", "pmid": "1834753", "source": "J Manipulative Physiol Ther. 1991;14(7):409-415", "title": "The Neck Disability Index: a study of reliability and validity" }, "formula": "ndi", "formula_expression": "NDI = pain_intensity + personal_care + lifting + reading + headaches + concentration + work + driving + sleeping + recreation; each caller-assigned 0-5; Vernon 1991 ten sections; max 50; raw 0-50 bands 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, >34 complete", "max_score": 50, "score": 0, "disability": "none" } ``` ## Errors - HTTP 400 `invalid_ndi`: NDI needs the ten Vernon 1991 sections each as an integer 0-5. Returned before settlement; you are not charged. - HTTP 400 `invalid_ndi_item`: each NDI section must be an integer from 0 to 5 (Vernon 1991). Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [Barthel Index](https://magentlab.com/docs/barthel) — Sum ten caller-assigned Mahoney 1965 Barthel Index item points and return the published 0-100 total. - [Modified Rankin](https://magentlab.com/docs/modified-rankin) — Return the van Swieten 1988 modified Rankin handicap grade 0-5 from a caller-assigned integer, with the published grade wording. ## Payment Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/docs/mcp ## Guarantees - HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON. - exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE. - HTTP 402 is unpaid only. Do not sign a second authorization because of a 503. - Execution is timeout-bounded and concurrency-capped. - Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.