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P18.1 Pain stimulation by using synchronised somatosensory evoked potentials (SSEPs) and contact heat evoked potentials (CHEPs)
Posters / Clinical Neurophysiology 117 (2006) S121–S336
appropriate nerves. Common anatomic variants were included. Conclusions: An organized comprehensive map of the motor innervation of the lumbosacral spine allows the physician to increase the accuracy, efficacy, and distribution of botulinum toxin for chemical denervation or other placement of electrodes in interventional procedures such as for the treatment of pain or spasticity. This could also assist the electromyographer in planning his/her study based upon the detection of neuronal injury or the pattern(s) of muscular changes in correlation with MR images. doi:10.1016/j.clinph.2006.06.394
P17.15 Sensorimotor integration in complex regional pain syndrome: A transcranial magnetic stimulation study A. Turton 1, C. McCabe 2, N. Harris 2, S.R. Filipovic 1 1 2
Burden Neurological Institute, UK The Royal National Hospital for Rheumatic Diseases, UK
Background: There is evidence that patients with Complex Regional Pain Syndrome (CRPS) have altered central sensorimotor processing. Sensory input can influence motor output either through indirect pathways or through direct connections from the sensory to motor cortex. Objective: To investigate sensorimotor interaction via direct connections in patients with CRPS and to compare the results with normal subjects. Method: Direct short-latency sensory–motor interaction was evaluated in eight patients with CRPS affecting a hand. Modulation of electromyographic (EMG) responses to transcranial magnetic stimulation (TMS) induced by concomitant median nerve stimulation, so-called short latency afferent inhibition, was measured. Results were compared with eight normal subjects who were age and sex matched with the patients. Results: As expected, all the normal subjects’ EMG responses to TMS with median nerve stimulation were smaller than responses to TMS alone. In seven of the eight CRPS patients, EMG responses to TMS were suppressed when paired with median nerve stimulation. Only one CRPS patient’s results showed no suppression of EMG responses. Conclusion: These results suggest that the disease mechanisms of CRPS do not typically affect the direct neural circuit between sensory and motor cortex and that normal sensory–motor interaction is occurring via this route. doi:10.1016/j.clinph.2006.06.395
P18.1 Pain stimulation by using synchronised somatosensory evoked potentials (SSEPs) and contact heat evoked potentials (CHEPs) D. Debatisse 1, C. Marcucci 1, J.G. Villemure 1, D.R. Sphan 2, E. Pralong 1
1 2
S209
CHUV, NCH-UNN, Switzerland CHUV, Aenesthesiology, Switzerland
Background: SSEPs evaluate conduction of non painful stimuli over large A-b fibres. Nociceptive stimuli generate action potentials conducted in thinner A-d and C fibres. These fibres are characterised by slower conduction velocities and can be evaluated by CHEPs. Objectives: To verify the feasibility of synchronised SSEPs and CHEPs in normal subjects, in order to create a new electrophysiological tool for clinical use. Methods: Twenty healthy normal subjects were investigated (10M/10F). SSEPs were triggered at the right posterior tibial nerve (8 ± 3 mA). Synchronised CHEPs were induced at the right S1 dermatome with a thermocouple at 52 °C (250 ms stimulus duration, 15 s inter stimulus interval, total number of stimuli: 90). Visual Analogue Scale (VAS) was obtained at the first stimulus and every 3 min thereafter. Acquisition of Evoked Potentials with on Fz (A1–A2) and CPz (A1–A2) derivations. Discussion: This study confirms the feasibility of recording SSEPs and CHEPs using concomitant stimulation. CHEPs induces a late N1-P1 component at 560 and 670 ms in Fz and CPz that may reflect A-d fibre activation. While VAS decreases with time, CHEPs and SSEPs amplitudes remain constant. Conclusion: These results suggest that pain perception is a ‘‘cognitive process’’ that is not solely dependent on Pain Evoked Potential amplitude. doi:10.1016/j.clinph.2006.06.396
P18.2 Distinction between cases with chronic neck–shoulder pain and healthy controls with parameters derived from surface array EMG measurements L. Kallenberg, H. Hermens, M. Vollenbroek-Hutten Roessingh Research and Development, Netherlands Background: Although several studies showed differences in EMG patterns between chronic neck–shoulder pain cases and healthy controls, the large inter-subject variability makes it hard to use parameters derived from EMG for diagnostic aims. Aim: To investigate the possibility of distinguishing neck–shoulder pain cases from healthy controls using a set of parameters derived from multi-channel EMG recordings. Methods: Fourteen controls and 13 cases performed a unilateral dynamic hand task, typing, editing, mouse and stress task. Array EMG of the trapezius was measured. Initial value and slope of global EMG parameters (RMS and RMSSLOPE) and median power frequency (FMED and FMEDSLOPE), number of motor unit action potentials per second (MUAP Rate) and MUAP shape properties (RMS and mean power frequency, FMEANMUAP) were
appropriate nerves. Common anatomic variants were included. Conclusions: An organized comprehensive map of the motor innervation of the lumbosacral spine allows the physician to increase the accuracy, efficacy, and distribution of botulinum toxin for chemical denervation or other placement of electrodes in interventional procedures such as for the treatment of pain or spasticity. This could also assist the electromyographer in planning his/her study based upon the detection of neuronal injury or the pattern(s) of muscular changes in correlation with MR images. doi:10.1016/j.clinph.2006.06.394
P17.15 Sensorimotor integration in complex regional pain syndrome: A transcranial magnetic stimulation study A. Turton 1, C. McCabe 2, N. Harris 2, S.R. Filipovic 1 1 2
Burden Neurological Institute, UK The Royal National Hospital for Rheumatic Diseases, UK
Background: There is evidence that patients with Complex Regional Pain Syndrome (CRPS) have altered central sensorimotor processing. Sensory input can influence motor output either through indirect pathways or through direct connections from the sensory to motor cortex. Objective: To investigate sensorimotor interaction via direct connections in patients with CRPS and to compare the results with normal subjects. Method: Direct short-latency sensory–motor interaction was evaluated in eight patients with CRPS affecting a hand. Modulation of electromyographic (EMG) responses to transcranial magnetic stimulation (TMS) induced by concomitant median nerve stimulation, so-called short latency afferent inhibition, was measured. Results were compared with eight normal subjects who were age and sex matched with the patients. Results: As expected, all the normal subjects’ EMG responses to TMS with median nerve stimulation were smaller than responses to TMS alone. In seven of the eight CRPS patients, EMG responses to TMS were suppressed when paired with median nerve stimulation. Only one CRPS patient’s results showed no suppression of EMG responses. Conclusion: These results suggest that the disease mechanisms of CRPS do not typically affect the direct neural circuit between sensory and motor cortex and that normal sensory–motor interaction is occurring via this route. doi:10.1016/j.clinph.2006.06.395
P18.1 Pain stimulation by using synchronised somatosensory evoked potentials (SSEPs) and contact heat evoked potentials (CHEPs) D. Debatisse 1, C. Marcucci 1, J.G. Villemure 1, D.R. Sphan 2, E. Pralong 1
1 2
S209
CHUV, NCH-UNN, Switzerland CHUV, Aenesthesiology, Switzerland
Background: SSEPs evaluate conduction of non painful stimuli over large A-b fibres. Nociceptive stimuli generate action potentials conducted in thinner A-d and C fibres. These fibres are characterised by slower conduction velocities and can be evaluated by CHEPs. Objectives: To verify the feasibility of synchronised SSEPs and CHEPs in normal subjects, in order to create a new electrophysiological tool for clinical use. Methods: Twenty healthy normal subjects were investigated (10M/10F). SSEPs were triggered at the right posterior tibial nerve (8 ± 3 mA). Synchronised CHEPs were induced at the right S1 dermatome with a thermocouple at 52 °C (250 ms stimulus duration, 15 s inter stimulus interval, total number of stimuli: 90). Visual Analogue Scale (VAS) was obtained at the first stimulus and every 3 min thereafter. Acquisition of Evoked Potentials with on Fz (A1–A2) and CPz (A1–A2) derivations. Discussion: This study confirms the feasibility of recording SSEPs and CHEPs using concomitant stimulation. CHEPs induces a late N1-P1 component at 560 and 670 ms in Fz and CPz that may reflect A-d fibre activation. While VAS decreases with time, CHEPs and SSEPs amplitudes remain constant. Conclusion: These results suggest that pain perception is a ‘‘cognitive process’’ that is not solely dependent on Pain Evoked Potential amplitude. doi:10.1016/j.clinph.2006.06.396
P18.2 Distinction between cases with chronic neck–shoulder pain and healthy controls with parameters derived from surface array EMG measurements L. Kallenberg, H. Hermens, M. Vollenbroek-Hutten Roessingh Research and Development, Netherlands Background: Although several studies showed differences in EMG patterns between chronic neck–shoulder pain cases and healthy controls, the large inter-subject variability makes it hard to use parameters derived from EMG for diagnostic aims. Aim: To investigate the possibility of distinguishing neck–shoulder pain cases from healthy controls using a set of parameters derived from multi-channel EMG recordings. Methods: Fourteen controls and 13 cases performed a unilateral dynamic hand task, typing, editing, mouse and stress task. Array EMG of the trapezius was measured. Initial value and slope of global EMG parameters (RMS and RMSSLOPE) and median power frequency (FMED and FMEDSLOPE), number of motor unit action potentials per second (MUAP Rate) and MUAP shape properties (RMS and mean power frequency, FMEANMUAP) were