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Updated: Dec 30, 2025
Establishing a Mouse Model of a Pure Small Fiber Neuropathy with the Ultrapotent Agonist of Transient Receptor Potential Vanilloid Type 1
Published on: February 13, 2018
Pain-related evoked potentials in patients with large, mixed, and small fiber neuropathy
Gabriela Siedler1, Claudia Sommer1, Nurcan Üçeyler1
1Department of Neurology, University of Würzburg, Germany.
Objective:
To investigate A-delta fiber pathways in patients with large, mixed, and small fiber neuropathies using pain-related evoked potentials (PREP).
Methods:
We prospectively examined consecutive and unselected 108 patients with neuropathies using PREP. Patients were stratified according to impaired fiber types in those with large fiber neuropathy (LFN, n = 23), mixed fiber neuropathy (MFN, n = 80), and small fiber neuropathy (SFN, n = 5). Additionally, medical history, nerve conduction studies, quantitative sensory testing (QST), and skin punch biopsy were applied. Data was compared with those of 49 healthy controls.
Results:
Patients with MFN showed a distal loss of PREP (16/80, 20%) and prolonged PREP latencies after stimulation at the foot (MFN: 225.8 [135-293.6] ms, controls: 218 [135-394] ms, p < 0.05). Patients with demyelinating neuropathies had prolonged PREP latencies after stimulation at the hand (p < 0.05 each). QST showed an impairment of small and large fiber function in patients with MFN. PREP were mostly absent in patients at advanced stages of neuropathies: in 10/31 (30%) patients with no recordable sural nerve action potential (SNAP, preserved SNAP: 8/76, 10% missing) and in 4/17 (24%) patients with loss of distal epidermal innervation (preserved epidermal innervation: 7/60, 24%) PREP was not recordable. PREP peak-to-peak amplitude after stimulation at the face was lowered in patients with reduced proximal intraepidermal nerve fiber density (p < 0.02).
Conclusion:
PREP is a useful screening method for A-delta fiber pathology also in patients with simultaneous large fiber pathology. Loss of PREP indicates advance stages of nerve fiber damage.
Significance:
PREP may be useful as a complementary method for detection of small fiber impairment also in patients with mixed fiber neuropathy and in advanced stages.
