Neurophysiologic assessment of small fibre damage in chemotherapy-induced peripheral neuropathy

• Published in: Clinical neurophysiology 2021-08, Vol.132 (8), p.1947-1956
• Main Authors: Isak, Baris, Tankisi, Hatice, Pugdahl, Kirsten, Ventzel, Lise, Finnerup, Nanna Brix, Fuglsang-Frederiksen, Anders
• Format: Article
• Language: English
• Subjects: Chemotherapy; Cutaneous silent period; Laser; Quantitative sensory testing; Small fibre
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2021.02.406

•Cutaneous silent period evoked with electrical (El-CSP) or laser (Ls-CSP) stimuli inform about peripheral nociceptive fibres.•Ls-CSP can help confirming small fibre (SF) damage, especially in cases with subtle changes on laser evoked potential.•El-CSP can help diagnosing SF-damage in labs using basic neurophysiologic tests. In patients with chemotherapy-induced peripheral neuropathy (CIPN), demonstration of small fibre (SF) damage is important to understand chronic late effects. Thirty patients having complaints compatible with possible CIPN following treatment with oxaliplatin or docetaxel were compared with 27 healthy subjects. All subjects were evaluated with quantitative sensory testing (QST) assessing SF function and laser evoked potentials (LEP). In addition, SF-damage was assessed using cutaneous silent periods evoked with electrical (El-CSP) and laser (Ls-CSP) stimuli. For LEP, N2P2 amplitudes were significantly smaller in patients than controls in both upper (P = 0.007) and lower extremities (P = 0.002), and the N1 amplitude in upper extremities of patients were significantly smaller than in controls (P = 0.001). SF-QST, LEP, Ls-CSP, and El-CSP were abnormal in 10 (33.3%), 16 (53.3%), 19 (63.3%), and 24 (80%) of CIPN patients, respectively. In patients with possible CIPN, El-CSP and Ls-CSP were more often abnormal than LEP and QST. This is probably because El-CSP and Ls-CSP inform mainly about peripheral nociceptive fibres, while LEP and QST inform about peripheral and central nociceptive pathways together. LEP and QST are established methods to detect SF-damage. El- and Ls-CSP might help clinicians in diagnosing SF-damage.