Continuous, non-invasive monitoring of bladder filling in patients with adult neurogenic lower urinary tract dysfunction (ANLUTD) remains an unmet clinical need. This study presents the first-in-human clinical evaluation of a wearable near-infrared (NIR) device (inContAlert BladderMate) for continuous daytime bladder monitoring under real-world conditions, with the aim of assessing feasibility and event-based detection of clinically relevant bladder filling (≥300 ml).

This study is part of an ongoing prospective trial currently being conducted at a specialized spinal cord injury center. The investigated wearable device utilizes near-infrared light to continuously estimate bladder filling and does not require gel, in contrast to conventional ultrasound-based technologies. The system provides user feedback when a predefined bladder volume threshold is reached, recommending bladder emptying. In this preliminary analysis, a 47-year-old female patient with paraplegia and ANLUTD was included. Bladder emptying was performed via intermittent catheterization. The patient used the device during daily activities. According to the instructions for use, the device should be positioned above the suprapubic region using a custom textile fixation strap. Device performance was evaluated using event-based analysis of catheterization episodes. The detection rate was defined as the proportion of catheterization events with a voided volume ≥300 ml that were correctly preceded by a device notification indicating the threshold had been reached. The voided volume during catheterization was used as the reference standard. A correct detection was recorded when the device notification (indicating ≥300 ml and recommending emptying) corresponded to a measured voided volume ≥300 ml.

In total, 29 valid voiding events were recorded and included in the analysis. The device was used over 17 days with a mean daily wear time of 8.31 ± 1.92 hours. Two notifications have been issued at a bladder filling of 250 ml (6.9%). Five notifications have not been issued when a bladder filling of ≥300 ml was reached (17.2%). 22 events were correctly detected, corresponding to a detection rate of 75.9%. The device was well tolerated, and no adverse events occurred. Integration into the patient’s daily routine over the 17-day monitoring period was feasible without any reported problems.

This first-in-human application demonstrates the feasibility of continuous, non-invasive bladder monitoring using a wearable NIR device under real-world conditions. The observed detection rate of 75.9% for a clinically relevant threshold of 300 ml is promising. Analysis of delayed detections suggests that suboptimal device positioning was a major contributing factor. Inconsistent use of the recommended suprapubic fixation resulted in suboptimal sensor alignment, likely reducing signal quality. Notably, these metrics were maintained without supervision in daily home routines. When applying a threshold of 250 ml, the system demonstrates a robust detection rate of 82.8%, affirming its utility for real-world ambulatory monitoring.

While these findings should be interpreted in the context of a single-patient feasibility analysis, wearable NIR technology shows potential for continuous and non-invasive detection of clinically relevant bladder filling thresholds. Initial results demonstrate promising performance and feasibility in ANLUTD. With improved fixation strategies and validation in larger cohorts, this approach may support more timely and individualized bladder emptying and help reduce the risk of bladder overdistension.

Continence 19S (2026) 102568
DOI: 10.1016/j.cont.2026.102568