title: Pre-perceptual pain sensory responses (N1 component) in type 1 diabetes mellitus.
abstract: We investigated the integrity of the ascending pathways for pain sensitivity in the early stage of type 1 diabetes mellitus, by measuring the N1 component and the conventional N2/P2 vertex potentials of laser evoked potentials (LEPs). Brain responses to laser stimuli were obtained in 21 healthy volunteers and 21 type 1 diabetic patients, without either clinical neuropathy or electrophysiological evidence of large-fiber damage. In diabetic patients N1 and P2 latencies were prolonged and the N1 and N2/P2 amplitudes were decreased after foot stimulation. A significant reduction of the conduction velocity of Adelta fibers in the lower limbs was also observed. LEPs reveal an early, subclinical and selective damage of pain sensation in diabetic patients. N1 and P2 potentials are delayed and decreased in parallel giving evidence that LEP abnormalities are not secondary to a cognitive dysfunction and mostly reflect a small-fiber dysfunction.
authors.affiliation: Institute of Neurology, La Sapienza, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Rossi
authors.forename: Susanna
authors.initials: S
authors.lastname: Morano
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.forename: Annarita
authors.initials: A
authors.lastname: Gabriele
authors.forename: Umberto
authors.initials: U
authors.lastname: Di Mario
authors.forename: Cristoforo
authors.initials: C
authors.lastname: Morocutti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pozzessere
mesh_terms: D000344:Afferent Pathways / Q000473:pathology / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000473:pathology / Q000503:physiopathology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D007834:Lasers; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology; D009619:Nociceptors / Q000473:pathology / Q000502:physiology*; D010146:Pain / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D010525:Peripheral Nerves / Q000473:pathology / Q000503:physiopathology*; D010812:Physical Stimulation; D011930:Reaction Time / Q000502:physiology