title: Diagnostic accuracy of laser-evoked potentials in diabetic neuropathy.
abstract: Although the most widely agreed neurophysiological tool for investigating small fiber damage is laser-evoked potential (LEP) recording, no study has documented its diagnostic accuracy. In this clinical, neurophysiological, and skin biopsy study, we collected age-corrected LEP normative ranges, verified the association of LEPs with pinprick sensory disturbances in the typical diabetic mixed fiber polyneuropathy, and assessed the sensitivity and specificity of LEPs in diabetic small fiber neuropathy. From 288 LEP recordings from the face, hand, and foot in 73 healthy subjects, we collected age-corrected normative ranges for LEPs. We then selected 100 patients with mixed-fiber diabetic neuropathy and 25 patients with possible small-fiber diabetic neuropathy. In the 100 patients with mixed fiber neuropathy, we verified how LEP abnormalities were associated with clinically evident pinprick sensory disturbances. In the 25 patients with possible pure small fiber neuropathy, using the skin biopsy for assessing the intraepidermal nerve fiber density as a reference standard, we calculated LEP sensitivity and specificity. In healthy participants, age strongly influenced normative ranges for all LEP variables. By applying age-corrected normative ranges for LEPs, we found that LEPs were strongly associated with pinprick sensory disturbances. In relation to the skin biopsy findings, LEPs yielded 78% sensitivity and 81% specificity in the diagnosis of diabetic small fiber neuropathy. Our study, providing age-corrected normative ranges for the main LEP data and their diagnostic accuracy, helps to make LEPs more reliable as a clinical diagnostic tool, and proposes this technique as a less invasive alternative to skin biopsy for diagnosing diabetic small fiber neuropathy.
authors.affiliation: aDepartment of Neurology and Psychiatry, Sapienza University, Rome, Italy bDivision of Neurology, Ospedale Pediatrico Bambino Gesú, IRCCS, Rome, Italy cCenter for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark dNeurology Unit, San Pio X Clinic, Fondazione Opera San Camillo, Milan, Italy eDepartment of Internal Medicine, Sapienza University, Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Di Stefano
authors.forename: Silvia
authors.initials: S
authors.lastname: La Cesa
authors.forename: Caterina
authors.initials: C
authors.lastname: Leone
authors.forename: Alessia
authors.initials: A
authors.lastname: Pepe
authors.forename: Eleonora
authors.initials: E
authors.lastname: Galosi
authors.forename: Marco
authors.initials: M
authors.lastname: Fiorelli
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Valeriani
authors.forename: Marco
authors.initials: M
authors.lastname: Lacerenza
authors.forename: Mario
authors.initials: M
authors.lastname: Pergolini
authors.forename: Antonella
authors.initials: A
authors.lastname: Biasiotta
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cruccu
authors.forename: Andrea
authors.initials: A
authors.lastname: Truini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology*; D003943:Diagnostic Techniques, Neurological; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials; D007834:Lasers; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D010775:Photic Stimulation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult