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# FDA Accepts Wearable Sensor-Based Foot Drop Measure for Trials
- URL: https://www.fdaweb.com/fda-accepts-wearable-sensor-based-foot-drop-measure-for-trials-d5161821/
- Published: 2026-09-23T16:00:00.000Z
- Updated: 2026-09-23T16:00:00.000Z
- Author: David McFarland
- Tags: Drugs, Legacy-ID-D5161821, #Import 2026-09-24 19:50

FDA has accepted a letter of intent (LOI) for a wearable sensor-based digital outcome measure designed to assess foot drop severity and gait impairment in patients with Charcot-Marie-Tooth disease type 1A (CMT1A), marking the first digital health technology for a rare neurological condition accepted into the agency's Innovative Science and Technology Approaches for New Drugs (ISTAND) program. The agency says the digital measurement tool is intended for use as an efficacy endpoint in clinical trials evaluating treatments for CMT1A, a progressive inherited peripheral neuropathy affecting approximately one in 5,000 people. There are currently no FDA-approved therapies for the condition.

The proposed tool uses movement sensors attached to patients' ankles and feet during a six-minute walk test conducted at scheduled clinic visits. It captures quantitative measurements of foot drop, including ankle range of motion, foot drop angle and mid-swing foot angle, to assess disease progression and potential treatment-related improvements.

[FDA said](https://www.fda.gov/drugs/drug-alerts-and-statements/fda-accepts-wearable-sensor-derived-foot-drop-metrics-under-istand-longitudinal-outcome-measures?ref=fdaweb.com) the technology could provide objective, continuous, high-resolution measurements that are more sensitive to treatment-related changes than existing clinical scales.

Acceptance of the LOI represents the first step in FDA's three-stage drug development tool qualification process and does not constitute qualification of the proposed measure for regulatory use. Launched in 2020, the ISTAND program supports the development of innovative drug development tools that do not readily fit into existing qualification pathways, including novel digital health technologies and other approaches intended to address unmet needs in drug development.