# HINTS Examination Interpreter (Kattah 2009)

> HINTS Examination Interpreter (Kattah 2009) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Applies the Kattah 2009 three-step HINTS protocol to caller-assigned exam findings to classify acute vestibular syndrome as central (dangerous) or peripheral (benign).

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/hints
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hints-examination-interpreter-kattah-2009-d3b90981
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Pj68pzyFDlNyiljapKvCm

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability hints-examination-interpreter-kattah-2009-d3b90981
```

Example prompt: Run the HINTS exam calculation for a patient in acute vestibular syndrome: the head-impulse test is normal (abnormal sign), there is no direction-changing nystagmus, and there is no skew deviation — is the presentation central or peripheral?

## When to prefer this

Use this endpoint when a clinician or clinical AI agent has already examined a patient in established acute vestibular syndrome (AVS) and has explicit boolean findings for the three HINTS components. Prefer this over general dizziness triage tools when the patient has already been screened into AVS and you need the Kattah 2009 risk stratification specifically. Not a substitute for HINTS-plus (which includes hearing), neuroimaging, or neurological consultation.

## Known failure modes

- Missing required query parameters (head_impulse_normal, direction_changing_nystagmus, or skew_deviation) returns an error
- Non-boolean parameter values may cause validation failure
- Endpoint classifies based solely on caller-assigned flags; incorrect clinical input yields unreliable output
- Not applicable outside the setting of established acute vestibular syndrome (AVS)

## How this service works

Kattah 2009 three-step HINTS (Head-Impulse, Nystagmus, Test-of-Skew) for patients already in acute vestibular syndrome (AVS). Three caller-assigned flags: head_impulse_normal, direction_changing_nystagmus, and skew_deviation. dangerous is true if any flag is true (INFARCT: Impulse Normal, Fast-phase Alternating, Refixation on Cover Test). benign iff none. Not HINTS-plus (hearing). Not a stroke diagnosis or a substitute for neuroimaging. magent does not examine the patient.

## Output

Returns a classification of the acute vestibular syndrome presentation as either dangerous (central, consistent with infarct) if any of the three INFARCT signs are present — normal head-impulse test, direction-changing nystagmus, or skew deviation — or benign (peripheral) if none are present. Does not diagnose stroke and does not substitute for neuroimaging.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "head_impulse_normal",
      "direction_changing_nystagmus",
      "skew_deviation"
     ],
     "properties": {
      "skew_deviation": {
       "type": "boolean",
       "description": "Skew deviation / vertical ocular misalignment on cover test as assigned by the caller (Kattah 2009). true is a dangerous central sign (INFARCT: Refixation on Cover Test). magent does not examine the patient."
      },
      "head_impulse_normal": {
       "type": "boolean",
       "description": "Normal horizontal head-impulse test (h-HIT) as assigned by the caller (Kattah 2009). true is a dangerous central sign (INFARCT: Impulse Normal). magent does not examine the patient."
      },
      "direction_changing_nystagmus": {
       "type": "boolean",
       "description": "Direction-changing nystagmus in eccentric gaze as assigned by the caller (Kattah 2009). true is a dangerous central sign (INFARCT: Fast-phase Alternating). magent does not examine the patient."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hints-examination-interpreter-kattah-2009-d3b90981/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)