AMT-4 abbreviated mental test (Swain)

AMT-4

Sum the four Swain 1997 AMT-4 items from caller-assigned correct/incorrect flags and return whether the score is less than 4 (impaired).

LIVE $0.005 USDC GET /api/calc/amt_4

Markdown: /docs/amt-4.md · Canonical: https://magentlab.com/docs/amt-4

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Sum the four Swain 1997 AMT-4 items from caller-assigned correct/incorrect flags and return whether the score is less than 4 (impaired).

When to use

When an agent already has AMT-4 items assigned as correct or incorrect (age, date of birth, place, year) and needs the published 0–4 total and impaired flag, not a dementia diagnosis and not Hodkinson 1972 AMT-10.

When not to use

Not a medical device and not a dementia diagnosis. magent does not interview the patient.
Each item is a caller-assigned boolean (age_correct, dob_correct, place_correct, year_correct). This API does not collect an age, date of birth, place name, or year.
Impaired is true when the AMT-4 score is less than 4 (Swain 1997). Score 4 is not impaired. This is a screening total, not a diagnosis.
This is Swain 1997 AMT-4 only. It is not Hodkinson 1972 AMT-10.

Formula

AMT-4 = age_correct + dob_correct + place_correct + year_correct; each 1 if true; max 4; impaired iff score < 4 (Swain 1997)

Citation

Title: Evaluation of a shortened version of the Abbreviated Mental Test in a series of elderly patients
Authors: Swain DG, Nightingale PG
Source: Clin Rehabil. 1997;11(3):243-248
DOI: 10.1177/026921559701100308

Worked example

All four items correct

Given: age_correct=truedob_correct=trueplace_correct=trueyear_correct=true

age_correct, dob_correct, place_correct, and year_correct are true as assigned by the caller
Score = 4 (max 4); impaired false

Age incorrect, other items correct

Given: age_correct=falsedob_correct=trueplace_correct=trueyear_correct=true

age_correct false → 0; the other three items true → 1 each
Score = 3 (max 4); impaired true because score < 4

Also searched as

AMT-4
Abbreviated Mental Test 4
Swain AMT-4
AMT4
four-item abbreviated mental test
AMT-4 cognitive screen
abbreviated mental test four items
Swain 1997 AMT-4

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/amt_4?age_correct=true&dob_correct=true&place_correct=true&year_correct=true

Full URL: https://api.magentlab.com/api/calc/amt_4?age_correct=true&dob_correct=true&place_correct=true&year_correct=true

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/amt_4?age_correct=true&dob_correct=true&place_correct=true&year_correct=true"

Parameters

Name	Type	Required	Description
`age_correct`	boolean	required	Caller-assigned flag: age stated correctly (Swain 1997 AMT-4). true scores 1; false scores 0. magent does not interview the patient and does not collect an age.
`dob_correct`	boolean	required	Caller-assigned flag: date of birth stated correctly (Swain 1997 AMT-4). true scores 1; false scores 0. magent does not collect a date of birth.
`place_correct`	boolean	required	Caller-assigned flag: place stated correctly (Swain 1997 AMT-4). true scores 1; false scores 0. magent does not collect a place name.
`year_correct`	boolean	required	Caller-assigned flag: current year stated correctly (Swain 1997 AMT-4). true scores 1; false scores 0. magent does not collect a year.

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.

POST /api/calc/amt_4 Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 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 (fixture)

{
  "items": [
    {
      "age_correct": "true",
      "dob_correct": "true",
      "place_correct": "true",
      "year_correct": "true"
    },
    {
      "age_correct": "true",
      "dob_correct": "true",
      "place_correct": "true",
      "year_correct": "true"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/amt_4",
  "items": [
    {
      "components": [
        {
          "factor": "age_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "dob_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "place_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "year_correct",
          "points": 1,
          "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": "Swain DG, Nightingale PG",
        "doi": "10.1177/026921559701100308",
        "id": "swain-1997",
        "pmid": "9360037",
        "source": "Clin Rehabil. 1997;11(3):243-248",
        "title": "Evaluation of a shortened version of the Abbreviated Mental Test in a series of elderly patients"
      },
      "formula": "amt_4",
      "formula_expression": "AMT-4 = age_correct + dob_correct + place_correct + year_correct; each 1 if true; max 4; impaired iff score < 4 (Swain 1997)",
      "max_score": 4,
      "score": 4,
      "impaired": false
    },
    {
      "components": [
        {
          "factor": "age_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "dob_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "place_correct",
          "points": 1,
          "present": true
        },
        {
          "factor": "year_correct",
          "points": 1,
          "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": "Swain DG, Nightingale PG",
        "doi": "10.1177/026921559701100308",
        "id": "swain-1997",
        "pmid": "9360037",
        "source": "Clin Rehabil. 1997;11(3):243-248",
        "title": "Evaluation of a shortened version of the Abbreviated Mental Test in a series of elderly patients"
      },
      "formula": "amt_4",
      "formula_expression": "AMT-4 = age_correct + dob_correct + place_correct + year_correct; each 1 if true; max 4; impaired iff score < 4 (Swain 1997)",
      "max_score": 4,
      "score": 4,
      "impaired": false
    }
  ]
}

Response

Field	Type	Description
`formula`	string	amt_4
`formula_expression`	string	Exact expression used
`score`	integer	AMT-4 points 0-4 (Swain 1997)
`max_score`	integer	Always 4
`impaired`	boolean	true when score is less than 4 (0–3 impaired; 4 not impaired). Swain 1997 screening total, not a dementia diagnosis.
`components`	array	Per-item points
`citation`	object	Swain 1997 Clin Rehabil citation
`disclaimer`	string	Not-a-device notice

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "components": [
    {
      "factor": "age_correct",
      "points": 1,
      "present": true
    },
    {
      "factor": "dob_correct",
      "points": 1,
      "present": true
    },
    {
      "factor": "place_correct",
      "points": 1,
      "present": true
    },
    {
      "factor": "year_correct",
      "points": 1,
      "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": "Swain DG, Nightingale PG",
    "doi": "10.1177/026921559701100308",
    "id": "swain-1997",
    "pmid": "9360037",
    "source": "Clin Rehabil. 1997;11(3):243-248",
    "title": "Evaluation of a shortened version of the Abbreviated Mental Test in a series of elderly patients"
  },
  "formula": "amt_4",
  "formula_expression": "AMT-4 = age_correct + dob_correct + place_correct + year_correct; each 1 if true; max 4; impaired iff score < 4 (Swain 1997)",
  "max_score": 4,
  "score": 4,
  "impaired": false
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_flag`	boolean clinical flags must be true or false Returned before settlement; you are not charged.
400	`invalid_amt_4`	each AMT-4 item must be true or false as assigned by the caller (Swain 1997). Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

4AT — Sum the Bellelli 2014 4AT items and return unlikely (0), possible cognitive impairment (1–3), or possible delirium (≥4).

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. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /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.