Bumps Test

bumps test plate

Figure 1.  Bumps Device showing grid layout and size.  This device consists of photoresist bumps fabricated on a ground glass substrate.

 

plan view of single bump

Figure 2.  White Light Interferometry (WLI) image of a single bump, replicated in plastic using hot embossing.

Bump detection threshold by group

Figure 3.  Mean (SEM) bump detection thresholds for all healthy subjects (Control) and all patients (All) with neuropathy. Patients were subdivided according to those with sensory symptoms in the feet only (Feet) and those in whom symptoms were also reported in the hands (Hands). *** Significant difference from control; ### significant difference from feet. (p=0.001)

Bump detection accuracy percentage by group

Figure 4.  The percent of healthy subjects (Control), all neuropathy patients (Neuropathy), and the subgroup of patients with sensory symptoms in the hands (Hands) that identified individual bumps on their first trial.

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A rapid, sensitive method to quantify tactile threshold of finger pads for early detection and staging of peripheral neuropathy and for use in clinical trials.

The Bumps device is a checkerboard-like smooth surface with 12 squares; each square encloses 5 colored circles. The subject explores the circles of each square with the index finger pad to locate the one circle containing a small bump.  Bumps in different squares have different heights.  All bumps are cylindrical, 550 microns in diameter and range from 0.5 microns up to 26 microns in height.

Detection threshold is defined as the smallest bump height detected. In some subjects, a 3-mm skin biopsy from the tested finger pad was taken to compare density of Meissner corpuscles to bump detection thresholds.1 The sensory organs activated by the finger striking a bump are the Meissner's Corpuscles that are present on the ridges of the fingerprint.

Kennedy WR, Selim MM, Brink TS, Hodges JS, Wendelschafer-Crabb G, Foster SX, Nolano M, Provitera V, Simone DA. A new device to quantify tactile sensation in neuropathy. Neurology. 2011;76:1642-1649. PMID: 21555731.

U.S. Patent No. 8,133,189 B2 (issued Mar. 13, 2012).

NIH Grant 2R42TR000462-02  The Bumps: a device for rapid non invasive quantification of touch sensation