Search results for "Laser-evoked potentials"

Differential effects on the laser evoked potential of selectively attending to pain localisation versus pain unpleasantness

2004

Abstract Objective : To determine the effects on the laser evoked potential (LEP) of selectively attending to affective (unpleasantness) versus sensory-discriminative (localisation) components of pain. Methods : LEPs, elicited by painful CO 2 laser stimulation of two areas of the right forearm, were recorded from 62 electrodes in 21 healthy volunteers, during three tasks that were matched for generalised attention: Localisation (report stimulus location), Unpleasantness (report stimulus unpleasantness), Control (report pain detection). LEP components are named by polarity, latency, and electrode. Results : N300-T7 peak amplitude was significantly greater during Localisation than Unpleasantn…

Differential nociceptive deficits in patients with borderline personality disorder and self-injurious behavior: laser-evoked potentials, spatial disc…

2003

Approximately 70-80% of women meeting criteria for borderline personality disorder (BPD) report attenuated pain perception or analgesia during non-suicidal, intentional self-mutilation. The aim of this study was to use laser-evoked potentials (LEPs) and psychophysical methods to differentiate the factors that may underlie this analgesic state. Ten unmedicated female patients with BPD (according to DSM-IV) and 14 healthy female control subjects were investigated using brief radiant heat pulses generated by a thulium laser and five-channel LEP recording. Heat pulses were applied as part of a spatial discrimination task (two levels of difficulty) and during a mental arithmetic task. BPD patien…

Attention to pain is processed at multiple cortical sites in man.

2004

Painful cutaneous laser stimuli evoked potentials (LEPs) were recorded over the primary somatosensory (SI), parasylvian, and medial frontal (MF) cortex areas in a patient with subdural electrode grids located over these areas for surgical treatment of epilepsy. The amplitudes of the negative (N2*) and positive (P2**) LEP peaks over SI, parasylvian, and MF cortex were enhanced by attention to (counting stimuli), in comparison with distraction from the stimulus (reading for comprehension). Late positive deflections following the P2** peak (late potential—LP) were recorded over MF and from the lateral premotor regions during attention but not during distraction. These findings suggest that att…

Laser-evoked potentials for assessment of nociceptive pathways in humans

1998

I n their Focus article, Chen, Arendt-Nielsen, and Plaghki [8] provide a comprehensive review of the . literature o~ human evoked potentials that ~re elicited by noxious heat, usually generated by Infrared laser stimulators. From this review, we identified four issues that may deserve a comment: (1) Standardize the experiment or its scientific report? (2) Nociception and pain. (3) What do laser-evoked potentials (LEPs) really measure? (4) Rational clinical use. For the sake of brevity, we do not attempt to quote all relevant literature; a complete literature survey can be found in a recent review paper by Bromm and Lorenz [4].

Clinical usefulness of laser-evoked potentials

2003

In contrast to the function of the visual or auditory pathways which are electrophysiologically accessible by visual or auditory evoked potentials, the somatosensory pathway cannot be investigated as a whole by conventional somatosensory evoked potentials (SEP), because these only reflect function of large fibers, dorsal columns, medial lemniscus and their thalamo-cortical projections mediating sensations like touch and vibration. The other half of the somatosensory system, signaling temperature and pain perception, uses a different set of afferents and different central pathways, the function of which is accessible by laser-evoked potentials (LEPs). LEP can document lesions of the spinotha…

Neurophysiological studies of pain pathways in peripheral and central nervous system disorders.

2003

Standard clinical neurophysiological assessment of somatosensory pathways by sensory evoked potentials (SEPs) is limited to the tactile and proprioceptive systems consisting of large fibers in the peripheral nerve, the dorsal columns of the spinal cord and the medial lemniscus in the brainstem. This limitation means that about half of the lesions in the somatosensory system will not be detectable. In recent years, many clinical studies have confirmed that laser evoked potentials (LEPs) allow the assessment of the other half of the somatosensory system. Rapid heating of the skin by infrared laser pulses specifically activates the nociceptive and thermoreceptive pathways consisting of small f…

13 LASER-EVOKED POTENTIALS IN PERIPHERAL NEUROPATHY

2007

Recommendations for the clinical use of somatosensory-evoked potentials

2008

The International Federation of Clinical Neurophysiology (IFCN) is in the process of updating its Recommendations for clinical practice published in 1999. These new recommendations dedicated to somatosensory-evoked potentials (SEPs) update the methodological aspects and general clinical applications of standard SEPs, and introduce new sections dedicated to the anatomical-functional organization of the somatosensory system and to special clinical applications, such as intraoperative monitoring, recordings in the intensive care unit, pain-related evoked potentials, and trigeminal and pudendal SEPs. Standard SEPs have gained an established role in the health system, and the special clinical ap…