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P1.5 The effect of gender on prepulse inhibition of the blink reflex
S60
Poster presentations: Poster session 1. Cranial nerves and spinal reflexes
system and there are few studies examining vestibular function in MD patients during quiescence and during an acute attack. Objective: To test whether dynamic otolith function is changed during the acute attack of M´ eni` ere’s Disease (MD) we measured dynamic otolith function in the same patients during the acute attack and compared these measures to those taken in the same patients during the quiescent phase between MD attacks. The two measures of dynamic otolith function were ocular and cervical vestibular-evoked myogenic potentials (oVEMPs and cVEMPs) produced in response to bone conducted vibration (BCV) of the midline of the forehead at the hairline (a location called Fz). Methods: Surface EMG electrodes measured responses to the 500 Hz Fz BCV either from beneath the eyes while the patient looked upwards the oVEMP or from over the stretched sternocleidomastoid muscles the cVEMP. In both cases the stimulus was repeated 7 ms bursts of 500 Hz vibration delivered by a hand-held Bruel & Kjaer 4810 minishaker (50 stimuli at a rate of 3/s). Results: During the MD attack there was a very large increase in the amplitude of the contralesional n10 of the oVEMP compared to quiescence, but there was a significant decrease in the ipsilesional p13 of the cVEMP during the attack compared to quiescence. Conclusion: In the acute MD attack, dynamic utricular function in the affected ear is enhanced, whereas dynamic saccular function in the affected ear is not similarly affected.
stimulation. Surface stimulation electrode was applied to the base of the penis dorsum. Surface recording electrode was applied above the bulbocavernosus muscle. We recorded the latency, calculated at onset, and the maximal amplitude of response, calculated peak to peak. Results: We were able to detect the bulbocavernosus reflex in all examined men. No correlation with age was found. The mean onset latency value was 33.0±4.85 ms (mean ±2 SD). The mean amplitude value was 16.53±12.21 mV (mean ±2 SD). Conclusion: Our normative data of bulbocavernosus reflex were similar to the ones previously published. This study provides normative values for the neurophysiologic study of bulbocavernosus reflex in a larger sample of patients.
P1.5 The effect of gender on prepulse inhibition of the blink reflex M. Kofler1 , H. Kumru2 , J. Schaller1 Department of Neurology, Hochzirl Hospital, Zirl, Austria, 2 Department of Neurology, Guttmann Institute, Badalona, Spain
1
Objectives: The effect of gender on prepulse inhibition of the blink reflex has not as yet been investigated. Methods: We studied the blink reflex bilaterally in 64 healthy volunteers (32 males, mean age = 40.7, SD = 13.2 years; 32 females, mean age = 39.7, SD = 11.7 years) following right supraorbital nerve stimulation (0.2 ms constant current square pulse, 10 times sensory threshold intensity, at least 10 s interstimulus interval). Single sweeps were amplified, filtered (30 3000 Hz), and recorded either alone (n = 8) or conditioned by a prepulse (0.5 ms constant current square pulse, 2 times sensory threshold intensity, 100 ms prior to supraorbital nerve stimulation) applied to the dominant index finger (60 right-handed subjects) though ring electrodes (n = 8). Latency and amplitude of the R1 component, as well as latency and area-under-the-curve of R2 and R2c (contralateral to stimulation) were measured in single traces and then averaged per subject. These mean values were then compared between males and females. Results: Unconditioned blink reflex R1 amplitude was larger in men (P < 0.01), while latencies of R1, R2, and R2c, as well as area of R2 and R2c did not differ between males and females. Prepulse stimulation caused a significant increase of R1 amplitude, and of R2 and R2c latency (P < 0.01 each). Prepulse inhibition of the area of R2 and R2c was significant in both males and females, with significantly more suppression in men (P < 0.05, each). Age had no significant influence on prepulse inhibition. Conclusions: These data indicate less prepulse inhibition of the blink reflex in females, consistent with more pronounced protective reflex activity as compared to males. This finding concurs with previous reports of gender differences in other protective reflexes, such as auditory startle reaction, flexor reflexes and cutaneous silent periods. P1.6 Bulbocavernosus reflex: normative data 1,2
1,2
3
1
1
G. Granata , L. Padua , F. Rossi , P. De Franco , C. Erra , V. Rossi Department of Neuroscience, Institute of Neurology, Catholic University, Rome, Italy, 2 Don C. Gnocchi Onlus Foundation, Italy, 3 Department of Neurology, Universit` a Federico II, Naples, Italy, 4 Servizio di Neurofisiopatologia, AORN Cardarelli, Naples, Italy
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1
Introduction: Bulbocavernosus reflex is the neurophysiological examination of the sacral reflex arc. In each patient with suspected urinary, bowel, or sexual neurogenic dysfunction, neurophysiological evaluation of the sacral segments should be performed. Previous normative data were obtained on small samples. Objective: The aim of this study is to determine normative values for the bulbocavernosus reflex in a large sample of men. Methods: We studied 105 male patients without central and peripheral neurological diseases. The sacral reflex was elicited after electrical
P1.7 Postural instability in Parkinson’s disease is not associated with depressed vestibulospinal reflex P. P¨ oschl1 , A. Janzen2 , W. Schulte-Mattler2 Krankenhaus der Barmherzigen Br¨ uder, Regensburg, Germany, 2 Neurologische Universit¨ atsklinik Regensburg, Regensburg, Germany 1
Introduction: Postural instability (PI) is one of the four principal symptoms of Parkinson’s disease (PD). Physiologically postural stability depends on intact vestibule-spinal reflexes (VSR). The VSR can be quantified by vestibular evoked myogenic potentials (VEMP). Recently, reduced VEMP amplitudes were reported in progressive supranuclear palsy (PSP). Objective: To study VEMPs in patients with PD. Methods: PD patients recruited from our outpatient clinic were prospectively examined. Disease duration, medication, dominant side of involvement, UPDRS score, PI UPDRS subscore were obtained. The accompanying spouses of the patients served as control group. Subjects with any vestibular symptoms or previous history of vestibular or auditory disease were excluded. Routine VEMP studies (click stimulation, 120 dB SPL, 5 Hz) were done in all subjects. Preinnervation was achieved by turning of the head contralateral to the click. Per ear, three runs were registered from each proband. Raw data of 128 stimuli were recorded per run. Preinnervation was quantified by the averaged root mean square (RMS) of EMG of the 50 ms pre-stimulus interval. Results: Twenty-three PD patients (age range 42 82 years, mean 65) and 16 healthy controls (age range 38 76, mean 65) were studied. Neither the normalized amplitudes nor the P13 latencies differed significantly between both groups. There was no correlation between VEMP amplitudes, latencies, and UPDRS scores. Conclusions: The findings argue against major involvement of the VSR in PI of patients with PD. The difference to the results from patients with PSP suggests that VSR alteration is different in these disorders. However, it is unclear to what extent methodological differences contribute to this difference. P1.8 Diagnostic value of vestibular evoked myogenic potentials (VEMP) in multiple sclerosis A. Pedrera-Mazarro1 , M. Carretero-García1 , L. Costa-Frossard2 , ´ lvarez-Cerme˜ enez2 J.C. A no2 , F. Paradinas-Jim´ 1 Department of Clinical Neurophysiology, Hospital Ram´ on y Cajal, on y Cajal, Madrid, Spain, 2 Department of Neurology, Hospital Ram´ Madrid, Spain Introduction: Patients with multiple sclerosis (MS) frequently report vestibular symptoms during the course of their diseases. Vestibular evoked myogenic potential (VEMP) testing is a non-invasive diagnostic technique to assess the vestibular function. It measures the vestibulocervical reflex that consists in an inhibitory potential recorded from sternocleidomastoid (SCM) muscle in response to loud sounds: a biphasic (positive-negative), high amplitude and low latency wave (p13-n23). It is a useful tool to asses sacule and inferior vestibular nerve function. Objectives: Our aim is to investigate VEMPs in patients with MS and to compare these findings with clinical and instrumental data. Method: We studied 32 patients (14 male, 18 female, mean age 36.25 years, range 12 to 59) with MS diagnosis. Each ear was stimulated separately by series of clicks (100 dB HL, 3 pps and duration 0.1 millisecond), and responses were recorded through surface electrodes in both SCM muscles (200 averages with low (10 Hz) and high (1.6 kHz) frequency filters). We studied the latencies of the p13-n23 positive-
Poster presentations: Poster session 1. Cranial nerves and spinal reflexes
system and there are few studies examining vestibular function in MD patients during quiescence and during an acute attack. Objective: To test whether dynamic otolith function is changed during the acute attack of M´ eni` ere’s Disease (MD) we measured dynamic otolith function in the same patients during the acute attack and compared these measures to those taken in the same patients during the quiescent phase between MD attacks. The two measures of dynamic otolith function were ocular and cervical vestibular-evoked myogenic potentials (oVEMPs and cVEMPs) produced in response to bone conducted vibration (BCV) of the midline of the forehead at the hairline (a location called Fz). Methods: Surface EMG electrodes measured responses to the 500 Hz Fz BCV either from beneath the eyes while the patient looked upwards the oVEMP or from over the stretched sternocleidomastoid muscles the cVEMP. In both cases the stimulus was repeated 7 ms bursts of 500 Hz vibration delivered by a hand-held Bruel & Kjaer 4810 minishaker (50 stimuli at a rate of 3/s). Results: During the MD attack there was a very large increase in the amplitude of the contralesional n10 of the oVEMP compared to quiescence, but there was a significant decrease in the ipsilesional p13 of the cVEMP during the attack compared to quiescence. Conclusion: In the acute MD attack, dynamic utricular function in the affected ear is enhanced, whereas dynamic saccular function in the affected ear is not similarly affected.
stimulation. Surface stimulation electrode was applied to the base of the penis dorsum. Surface recording electrode was applied above the bulbocavernosus muscle. We recorded the latency, calculated at onset, and the maximal amplitude of response, calculated peak to peak. Results: We were able to detect the bulbocavernosus reflex in all examined men. No correlation with age was found. The mean onset latency value was 33.0±4.85 ms (mean ±2 SD). The mean amplitude value was 16.53±12.21 mV (mean ±2 SD). Conclusion: Our normative data of bulbocavernosus reflex were similar to the ones previously published. This study provides normative values for the neurophysiologic study of bulbocavernosus reflex in a larger sample of patients.
P1.5 The effect of gender on prepulse inhibition of the blink reflex M. Kofler1 , H. Kumru2 , J. Schaller1 Department of Neurology, Hochzirl Hospital, Zirl, Austria, 2 Department of Neurology, Guttmann Institute, Badalona, Spain
1
Objectives: The effect of gender on prepulse inhibition of the blink reflex has not as yet been investigated. Methods: We studied the blink reflex bilaterally in 64 healthy volunteers (32 males, mean age = 40.7, SD = 13.2 years; 32 females, mean age = 39.7, SD = 11.7 years) following right supraorbital nerve stimulation (0.2 ms constant current square pulse, 10 times sensory threshold intensity, at least 10 s interstimulus interval). Single sweeps were amplified, filtered (30 3000 Hz), and recorded either alone (n = 8) or conditioned by a prepulse (0.5 ms constant current square pulse, 2 times sensory threshold intensity, 100 ms prior to supraorbital nerve stimulation) applied to the dominant index finger (60 right-handed subjects) though ring electrodes (n = 8). Latency and amplitude of the R1 component, as well as latency and area-under-the-curve of R2 and R2c (contralateral to stimulation) were measured in single traces and then averaged per subject. These mean values were then compared between males and females. Results: Unconditioned blink reflex R1 amplitude was larger in men (P < 0.01), while latencies of R1, R2, and R2c, as well as area of R2 and R2c did not differ between males and females. Prepulse stimulation caused a significant increase of R1 amplitude, and of R2 and R2c latency (P < 0.01 each). Prepulse inhibition of the area of R2 and R2c was significant in both males and females, with significantly more suppression in men (P < 0.05, each). Age had no significant influence on prepulse inhibition. Conclusions: These data indicate less prepulse inhibition of the blink reflex in females, consistent with more pronounced protective reflex activity as compared to males. This finding concurs with previous reports of gender differences in other protective reflexes, such as auditory startle reaction, flexor reflexes and cutaneous silent periods. P1.6 Bulbocavernosus reflex: normative data 1,2
1,2
3
1
1
G. Granata , L. Padua , F. Rossi , P. De Franco , C. Erra , V. Rossi Department of Neuroscience, Institute of Neurology, Catholic University, Rome, Italy, 2 Don C. Gnocchi Onlus Foundation, Italy, 3 Department of Neurology, Universit` a Federico II, Naples, Italy, 4 Servizio di Neurofisiopatologia, AORN Cardarelli, Naples, Italy
4
1
Introduction: Bulbocavernosus reflex is the neurophysiological examination of the sacral reflex arc. In each patient with suspected urinary, bowel, or sexual neurogenic dysfunction, neurophysiological evaluation of the sacral segments should be performed. Previous normative data were obtained on small samples. Objective: The aim of this study is to determine normative values for the bulbocavernosus reflex in a large sample of men. Methods: We studied 105 male patients without central and peripheral neurological diseases. The sacral reflex was elicited after electrical
P1.7 Postural instability in Parkinson’s disease is not associated with depressed vestibulospinal reflex P. P¨ oschl1 , A. Janzen2 , W. Schulte-Mattler2 Krankenhaus der Barmherzigen Br¨ uder, Regensburg, Germany, 2 Neurologische Universit¨ atsklinik Regensburg, Regensburg, Germany 1
Introduction: Postural instability (PI) is one of the four principal symptoms of Parkinson’s disease (PD). Physiologically postural stability depends on intact vestibule-spinal reflexes (VSR). The VSR can be quantified by vestibular evoked myogenic potentials (VEMP). Recently, reduced VEMP amplitudes were reported in progressive supranuclear palsy (PSP). Objective: To study VEMPs in patients with PD. Methods: PD patients recruited from our outpatient clinic were prospectively examined. Disease duration, medication, dominant side of involvement, UPDRS score, PI UPDRS subscore were obtained. The accompanying spouses of the patients served as control group. Subjects with any vestibular symptoms or previous history of vestibular or auditory disease were excluded. Routine VEMP studies (click stimulation, 120 dB SPL, 5 Hz) were done in all subjects. Preinnervation was achieved by turning of the head contralateral to the click. Per ear, three runs were registered from each proband. Raw data of 128 stimuli were recorded per run. Preinnervation was quantified by the averaged root mean square (RMS) of EMG of the 50 ms pre-stimulus interval. Results: Twenty-three PD patients (age range 42 82 years, mean 65) and 16 healthy controls (age range 38 76, mean 65) were studied. Neither the normalized amplitudes nor the P13 latencies differed significantly between both groups. There was no correlation between VEMP amplitudes, latencies, and UPDRS scores. Conclusions: The findings argue against major involvement of the VSR in PI of patients with PD. The difference to the results from patients with PSP suggests that VSR alteration is different in these disorders. However, it is unclear to what extent methodological differences contribute to this difference. P1.8 Diagnostic value of vestibular evoked myogenic potentials (VEMP) in multiple sclerosis A. Pedrera-Mazarro1 , M. Carretero-García1 , L. Costa-Frossard2 , ´ lvarez-Cerme˜ enez2 J.C. A no2 , F. Paradinas-Jim´ 1 Department of Clinical Neurophysiology, Hospital Ram´ on y Cajal, on y Cajal, Madrid, Spain, 2 Department of Neurology, Hospital Ram´ Madrid, Spain Introduction: Patients with multiple sclerosis (MS) frequently report vestibular symptoms during the course of their diseases. Vestibular evoked myogenic potential (VEMP) testing is a non-invasive diagnostic technique to assess the vestibular function. It measures the vestibulocervical reflex that consists in an inhibitory potential recorded from sternocleidomastoid (SCM) muscle in response to loud sounds: a biphasic (positive-negative), high amplitude and low latency wave (p13-n23). It is a useful tool to asses sacule and inferior vestibular nerve function. Objectives: Our aim is to investigate VEMPs in patients with MS and to compare these findings with clinical and instrumental data. Method: We studied 32 patients (14 male, 18 female, mean age 36.25 years, range 12 to 59) with MS diagnosis. Each ear was stimulated separately by series of clicks (100 dB HL, 3 pps and duration 0.1 millisecond), and responses were recorded through surface electrodes in both SCM muscles (200 averages with low (10 Hz) and high (1.6 kHz) frequency filters). We studied the latencies of the p13-n23 positive-