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P35.2 Cortical control of mental sweating in humans: Study on sympathetic skin responses evoked by subdural electrode stimulation
Posters / Clinical Neurophysiology 117 (2006) S121–S336
higher tier than V2, responds strongly to ICs, and that ICrelated activation in V1/V2 in fact might be driven by feedback input from the LOC. When Kanizsa-type ICs are modified by rounding the corners of the inducers and misaligning them slightly, the impression of an enclosed salient region (SR) remains, although ICs no longer are perceived. Stanley and Rubin (Neuron 2003;37:323–31) found that the LOC responded to SR, suggesting that the LOC subserves a rapid but crude region-based segmentation process preceding boundary completion in V1/V2. Aims: The present study examined the feedback hypothesis that IC-related activation in V1/V2 might be driven by input from the LOC. Methods: Fifteen healthy male subjects participated in the experiment. Written consent was obtained from all subjects after explanation of the study. The time course of cortical responses to ICs was compared with those to SR using high-density (74-channel) event-related potentials. Results: Scalp mapping indicated that shared negative modulation for ICs and SR was distributed bilaterally over the lateral occipital scalp at a latency of 70 to 180 ms. Slightly later, a weak negative modulation occurred with ICs but not SR at the occipital pole scalp from 170 to 180 ms. Dipoles for early and late modulations were fitted optimally in the LOC and occipital pole, respectively. Discussion: The present results suggested that IC-related cortical activation could be separated into region-based segmentation and subsequent boundary completion. doi:10.1016/j.clinph.2006.06.585
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The cough reflex was normal; coughing resulted with inhalation of 2.5% of citric acid; sensation was reported as tingling in the mid-line at the upper end of the sternum. When breathing increasing levels of inspired CO2 freely, IW reported breathing deeper and faster, with the lower neck as the site of the sensation, but did not report any sensation of air hunger even though ventilation had reached 27 l/min. Ventilatory sensitivity too was normal. As in normal controls, we were able to generate air hunger by ventilating the subject using a nasal mask at fixed respiratory frequency at a CO2 level of 47– 48 mmHg; if the tidal volume was then increased, whilst keeping CO2 constant, the sensation of air hunger was abolished, demonstrating the inhibitory power of lung stretch (Hering-Breuer); the sensation was again only perceived at the root of the neck. Discussion: In most tests IW’s breathing was remarkably normal. The studies suggest that air hunger maybe a centrally originating sensation, but one projected to the chest wall in the presence of large fibre afferents. Acknowledgement: We thank IW for his interest and cooperation. doi:10.1016/j.clinph.2006.06.586
P35.2 Cortical control of mental sweating in humans: Study on sympathetic skin responses evoked by subdural electrode stimulation K. Matsunaga 1, N. Akamatsu 2, T. Uozumi 2, E. Urasaki 3, S. Tsuji 2 1
P35.1 A study of human breathing after selective loss of large fibre sensory nerves below the neck J. Cole 1, K. Murphy 2, A. Guz 2 1
Poole Hospital, Clinical Neurophysiology, UK Charing Cross Hospital, Respiratory Medicine, Imperial College, UK
Kumamoto Kinoh Hospital, Department of Neurology, Japan 2 University of Occupational and Environmental Health, School of Medicine, Department of Neurology, Japan 3 University of Occupational and Environmental Health, School of Medicine, Department of Neurosurgery, Japan
2
Introduction: To investigate the sensations from breathing experiments were performed with a subject, IW, who has an acute sensory neuronopathy leaving him without touch, movement/position sense below C3 and hence who lacks intercostal afferents. Methods: A wide variety of respiratory investigations were performed and, where, relevant his perceptions sought. Results: Resting ventilation, O2 and CO2 levels, spirometry and vital capacity were normal, both seated and lying, with the subject able to generate normal maximum inspiratory and expiratory mouth pressures. Voluntary breathhold at the end of a normal expiration lasted for 27 s; a tight sensation was experienced at the root of the neck 10 s into the breathhold and rose until the break-point with no sensation in the chest or abdomen.
Background: Palmar and plantar sweating is mainly produced by mental stimulation and thus it is called mental sweating. The central mechanism of mental sweating may involve the cerebral cortex. However, the cortical area which has an excitatory influence on mental sweating has not been elucidated in humans. Objective: To investigate the cortical area which has an excitatory influence on mental sweating in humans, using SSRs evoked by subdural electrode stimulation. Patients and methods: The data were obtained from seven patients with medically intractable partial epilepsy (two men and five women, age 31–51 years). Six patients were evaluated for epilepsy surgery using chronically implanted subdural electrode grids. One patient was evaluated using bilateral depth electrodes in hippocampus. Functional cortical mapping was made using high frequency (50 Hz) cortical stimulation through subdural electrodes. SSRs were recorded from the hands and feet. We used high frequency
S288
Posters / Clinical Neurophysiology 117 (2006) S121–S336
(50 Hz) electrical stimulation of 1 s duration to evoke SSRs. Results: SSRs could be evoked by stimulation through electrodes over the primary sensorimotor and temporal cortices. Stimulation of the motor areas (M1) for face, tongue and eye movement or the sensory areas (S1) for face and tongue as well as M1 and S1 areas for the hand and foot could produce SSRs. SSRs could also be evoked by stimulation of the M1 for the hand and temporal cortex even at subthreshold intensities which did not produce any positive motor or psychic responses during the stimulation train. Conclusion: Sensorimotor and temporal cortical areas have an excitatory influence on mental sweating in humans. doi:10.1016/j.clinph.2006.06.587
P35.3 Autonomic tests in predominantly sensory neuropathy with normal nerve conduction tests V. Salanga 1, L. Flaherty 2 1 2
Cleveland Clinic Florida, Department of Neurology, USA Cleveland Clinic Florida, USA
Background: Routine nerve conduction tests (NCTs) for suspected peripheral polyneuropathy in the lower limbs usually include peroneal and/or tibial motor nerve and sural sensory nerve conduction studies. Patients with normal routine NCTs may have small fiber sensory neuropathy, which may be detected by autonomic tests (ATs). Thus, in patients with complaints of burning painful feet, normal clinical examination, and normal routine NCTs, ATs may be useful in diagnosing small fiber sensory neuropathy. Objective: To determine if patients with typical sensory neuropathic symptoms in the distal lower extremities and normal routine NCTs may have abnormal ATs. Methods: ATs in our laboratory include recording sympathetic skin responses (SSR) in the hand and foot, and cardiovagal responses (R-R intervals with deep breathing and Valsalva ratio). We reviewed patients with sensory neuropathic symptoms who had routine NCTs and ATs in our laboratory during the past 3 years. Results: Of 45 patients who had normal routine NCTs, 37 (82%) had abnormal ATs, and 8 (18%) had normal ATs. 29 of 37 (78%) patients had abnormal SSR and cardiovagal tests, 4 of 37 (11%) had abnormal cardiovagal tests only, and 4 of 37 (11%) had abnormal SSR only. Conclusion: Patients with complaints of burning pain and numbness in the distal lower limbs should be evaluated for sensory neuropathy. If routine NCTs are normal, autonomic tests should be performed. doi:10.1016/j.clinph.2006.06.588
P35.4 Effects of interictal epileptiform discharges on heart rate variability during sleep in patients with benign epilepsy with centrotemporal spikes Y. Li 1, P. Xie 1, Y. Wang 2, Y. Zhu 2, L. Kang 2 1
The First Affiliated Hospital, Chongqing University of Medical Sciences, Department of Neurology, China 2 The second Teaching Hospital of Yan’an University School of Medicine, Department of Neurology, China Background: Sudden unexpected deaths (SUDEP) are more serious problem in patients with epilepsy. Autonomic neuronal dysfunction has been associated with SUDEP but data regarding autonomic function in patients with benign epilepsy with centrotemporal spikes during sleep is not clear. Aims: In this study we have explored the effects of interictal epileptiform discharges on heart rate variability during sleep in patients with benign epilepsy with centrotemporal spikes. Patients and methods: Twenty-one patients with newly diagnosed benign epilepsy with centrotemporal spikes (BECTS£Ó) and twenty one healthy controls were studied. The polysomnogram was collected by a digital polygraph. ECG was synchronously monitored throughout the sleep. The spike-index and heart rate variability were calculated over 5 min periods. Results: LF components increased along with the depth of sleep in both groups, and reached peak in S4 stage. However, epileptic group had significantly greater LF components in S2, S3 and S4 stage (p < 0.05).The LF/HF ratio changed significantly with the sleep stages(p < 0.04 in control group; p < 0.02 in epileptic group): in deep sleep, it decreased, and in REM sleep, it increased. Patients with BECTS had a higher LF/HF ratio than control in all stages (p < 0.05), especially in S2 stages (p < 0.01). Conclusions: There is autonomic dysregulation in patients with benign epilepsy with centrotemporal spikes, especially during epileptic discharges. doi:10.1016/j.clinph.2006.06.589
P35.5 ACE genotype is associated with prolonged QTc in individuals with decreased heart rate variability during paced breathing A. Grandinetti 1, D. Chow 1, S. Seifried 1, D. Sletten 2, P. Low 2 1 2
University of Hawaii at Manoa, USA Mayo Clinic, USA
Background: Increased QT interval is a common electrocardiographic abnormality that is an important predictor of cardiovascular mortality. Recently, the angiotensin-converting enzyme (ACE) gene Insertion/Deletion polymorphism has been associated with QTc and QT dispersion, and in at least one study, associated with
higher tier than V2, responds strongly to ICs, and that ICrelated activation in V1/V2 in fact might be driven by feedback input from the LOC. When Kanizsa-type ICs are modified by rounding the corners of the inducers and misaligning them slightly, the impression of an enclosed salient region (SR) remains, although ICs no longer are perceived. Stanley and Rubin (Neuron 2003;37:323–31) found that the LOC responded to SR, suggesting that the LOC subserves a rapid but crude region-based segmentation process preceding boundary completion in V1/V2. Aims: The present study examined the feedback hypothesis that IC-related activation in V1/V2 might be driven by input from the LOC. Methods: Fifteen healthy male subjects participated in the experiment. Written consent was obtained from all subjects after explanation of the study. The time course of cortical responses to ICs was compared with those to SR using high-density (74-channel) event-related potentials. Results: Scalp mapping indicated that shared negative modulation for ICs and SR was distributed bilaterally over the lateral occipital scalp at a latency of 70 to 180 ms. Slightly later, a weak negative modulation occurred with ICs but not SR at the occipital pole scalp from 170 to 180 ms. Dipoles for early and late modulations were fitted optimally in the LOC and occipital pole, respectively. Discussion: The present results suggested that IC-related cortical activation could be separated into region-based segmentation and subsequent boundary completion. doi:10.1016/j.clinph.2006.06.585
S287
The cough reflex was normal; coughing resulted with inhalation of 2.5% of citric acid; sensation was reported as tingling in the mid-line at the upper end of the sternum. When breathing increasing levels of inspired CO2 freely, IW reported breathing deeper and faster, with the lower neck as the site of the sensation, but did not report any sensation of air hunger even though ventilation had reached 27 l/min. Ventilatory sensitivity too was normal. As in normal controls, we were able to generate air hunger by ventilating the subject using a nasal mask at fixed respiratory frequency at a CO2 level of 47– 48 mmHg; if the tidal volume was then increased, whilst keeping CO2 constant, the sensation of air hunger was abolished, demonstrating the inhibitory power of lung stretch (Hering-Breuer); the sensation was again only perceived at the root of the neck. Discussion: In most tests IW’s breathing was remarkably normal. The studies suggest that air hunger maybe a centrally originating sensation, but one projected to the chest wall in the presence of large fibre afferents. Acknowledgement: We thank IW for his interest and cooperation. doi:10.1016/j.clinph.2006.06.586
P35.2 Cortical control of mental sweating in humans: Study on sympathetic skin responses evoked by subdural electrode stimulation K. Matsunaga 1, N. Akamatsu 2, T. Uozumi 2, E. Urasaki 3, S. Tsuji 2 1
P35.1 A study of human breathing after selective loss of large fibre sensory nerves below the neck J. Cole 1, K. Murphy 2, A. Guz 2 1
Poole Hospital, Clinical Neurophysiology, UK Charing Cross Hospital, Respiratory Medicine, Imperial College, UK
Kumamoto Kinoh Hospital, Department of Neurology, Japan 2 University of Occupational and Environmental Health, School of Medicine, Department of Neurology, Japan 3 University of Occupational and Environmental Health, School of Medicine, Department of Neurosurgery, Japan
2
Introduction: To investigate the sensations from breathing experiments were performed with a subject, IW, who has an acute sensory neuronopathy leaving him without touch, movement/position sense below C3 and hence who lacks intercostal afferents. Methods: A wide variety of respiratory investigations were performed and, where, relevant his perceptions sought. Results: Resting ventilation, O2 and CO2 levels, spirometry and vital capacity were normal, both seated and lying, with the subject able to generate normal maximum inspiratory and expiratory mouth pressures. Voluntary breathhold at the end of a normal expiration lasted for 27 s; a tight sensation was experienced at the root of the neck 10 s into the breathhold and rose until the break-point with no sensation in the chest or abdomen.
Background: Palmar and plantar sweating is mainly produced by mental stimulation and thus it is called mental sweating. The central mechanism of mental sweating may involve the cerebral cortex. However, the cortical area which has an excitatory influence on mental sweating has not been elucidated in humans. Objective: To investigate the cortical area which has an excitatory influence on mental sweating in humans, using SSRs evoked by subdural electrode stimulation. Patients and methods: The data were obtained from seven patients with medically intractable partial epilepsy (two men and five women, age 31–51 years). Six patients were evaluated for epilepsy surgery using chronically implanted subdural electrode grids. One patient was evaluated using bilateral depth electrodes in hippocampus. Functional cortical mapping was made using high frequency (50 Hz) cortical stimulation through subdural electrodes. SSRs were recorded from the hands and feet. We used high frequency
S288
Posters / Clinical Neurophysiology 117 (2006) S121–S336
(50 Hz) electrical stimulation of 1 s duration to evoke SSRs. Results: SSRs could be evoked by stimulation through electrodes over the primary sensorimotor and temporal cortices. Stimulation of the motor areas (M1) for face, tongue and eye movement or the sensory areas (S1) for face and tongue as well as M1 and S1 areas for the hand and foot could produce SSRs. SSRs could also be evoked by stimulation of the M1 for the hand and temporal cortex even at subthreshold intensities which did not produce any positive motor or psychic responses during the stimulation train. Conclusion: Sensorimotor and temporal cortical areas have an excitatory influence on mental sweating in humans. doi:10.1016/j.clinph.2006.06.587
P35.3 Autonomic tests in predominantly sensory neuropathy with normal nerve conduction tests V. Salanga 1, L. Flaherty 2 1 2
Cleveland Clinic Florida, Department of Neurology, USA Cleveland Clinic Florida, USA
Background: Routine nerve conduction tests (NCTs) for suspected peripheral polyneuropathy in the lower limbs usually include peroneal and/or tibial motor nerve and sural sensory nerve conduction studies. Patients with normal routine NCTs may have small fiber sensory neuropathy, which may be detected by autonomic tests (ATs). Thus, in patients with complaints of burning painful feet, normal clinical examination, and normal routine NCTs, ATs may be useful in diagnosing small fiber sensory neuropathy. Objective: To determine if patients with typical sensory neuropathic symptoms in the distal lower extremities and normal routine NCTs may have abnormal ATs. Methods: ATs in our laboratory include recording sympathetic skin responses (SSR) in the hand and foot, and cardiovagal responses (R-R intervals with deep breathing and Valsalva ratio). We reviewed patients with sensory neuropathic symptoms who had routine NCTs and ATs in our laboratory during the past 3 years. Results: Of 45 patients who had normal routine NCTs, 37 (82%) had abnormal ATs, and 8 (18%) had normal ATs. 29 of 37 (78%) patients had abnormal SSR and cardiovagal tests, 4 of 37 (11%) had abnormal cardiovagal tests only, and 4 of 37 (11%) had abnormal SSR only. Conclusion: Patients with complaints of burning pain and numbness in the distal lower limbs should be evaluated for sensory neuropathy. If routine NCTs are normal, autonomic tests should be performed. doi:10.1016/j.clinph.2006.06.588
P35.4 Effects of interictal epileptiform discharges on heart rate variability during sleep in patients with benign epilepsy with centrotemporal spikes Y. Li 1, P. Xie 1, Y. Wang 2, Y. Zhu 2, L. Kang 2 1
The First Affiliated Hospital, Chongqing University of Medical Sciences, Department of Neurology, China 2 The second Teaching Hospital of Yan’an University School of Medicine, Department of Neurology, China Background: Sudden unexpected deaths (SUDEP) are more serious problem in patients with epilepsy. Autonomic neuronal dysfunction has been associated with SUDEP but data regarding autonomic function in patients with benign epilepsy with centrotemporal spikes during sleep is not clear. Aims: In this study we have explored the effects of interictal epileptiform discharges on heart rate variability during sleep in patients with benign epilepsy with centrotemporal spikes. Patients and methods: Twenty-one patients with newly diagnosed benign epilepsy with centrotemporal spikes (BECTS£Ó) and twenty one healthy controls were studied. The polysomnogram was collected by a digital polygraph. ECG was synchronously monitored throughout the sleep. The spike-index and heart rate variability were calculated over 5 min periods. Results: LF components increased along with the depth of sleep in both groups, and reached peak in S4 stage. However, epileptic group had significantly greater LF components in S2, S3 and S4 stage (p < 0.05).The LF/HF ratio changed significantly with the sleep stages(p < 0.04 in control group; p < 0.02 in epileptic group): in deep sleep, it decreased, and in REM sleep, it increased. Patients with BECTS had a higher LF/HF ratio than control in all stages (p < 0.05), especially in S2 stages (p < 0.01). Conclusions: There is autonomic dysregulation in patients with benign epilepsy with centrotemporal spikes, especially during epileptic discharges. doi:10.1016/j.clinph.2006.06.589
P35.5 ACE genotype is associated with prolonged QTc in individuals with decreased heart rate variability during paced breathing A. Grandinetti 1, D. Chow 1, S. Seifried 1, D. Sletten 2, P. Low 2 1 2
University of Hawaii at Manoa, USA Mayo Clinic, USA
Background: Increased QT interval is a common electrocardiographic abnormality that is an important predictor of cardiovascular mortality. Recently, the angiotensin-converting enzyme (ACE) gene Insertion/Deletion polymorphism has been associated with QTc and QT dispersion, and in at least one study, associated with