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P134 Electroneurographic (ENoG) evaluation of peripheral facial palsy (PFP). Early and late results in 500 patients
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Poster Session: Electromyography and Neurography H-REFLEXES IN CHRONIC LOW BACK PAIN
R. Mazzocchio, A. Bolognini, A. Mariottini, V.E Muzii, L. Palma, G. Rizzo, G.B. Scarfo'. Cattedra di Neurochirurgia, Universita' di Siena,
Italy The afferent limb of the Soleus H-reflex is very sensitive to the effects of peripheral nerve ischemic compression [1]. By analogy, it could be susceptible to the effects of repeated compression on lumbosacral nerve roots caused by intermittent narrowing of the vertebral canal due to segmental instability. We examined 15 patients (mean age 55, range 34-76) affected by chronic low back pain with radiologic evidence of isthmic spondylolisthesis, mostly at L4-L5 level. Pain was aggravated by standing, mechanical loads and poor posture. None of the patients had clinical or electrophysiological signs of peripheral nerve disfunction. Soleus H-reflexes were considered abnormal if the latency was above 2 SD from the mean of height-matched controls, if there was a side-to-side difference of more than 2 ms, or if the response was absent. In 7 out of 15 patients, H-reflexes were normal. In the remaining eight, the whole range of abnormalities was found: a) a side-to-side latency difference in three, b) a bilateral latency increase in two, c) a unilateral latency increase and lack of response in one, and d) a bilateral lack of response in two subjects. In these patients, low back pain was often associated with diffuse leg pain on standing; all but one had segmental instability above L5-S1 level, and H-reflexes abnormalities were mainly bilateral. This data rather than indicate an individual radiculopathy may be interpreted as a sign of chronic, symmetric constriction of the thecal sac with root injury occurring in the vertebral canal rather than in the respective neural foramina. S1 dorsal roots may be particularly liable to ischaemia and mechanical irritation because of their large size and long course in the spinal canal. We propose that soleus H-reflex testing may help detect early signs of multiple root injury in chronic low back pain due to segmental instability. Reference
[1] Rossi A, Mazzocchio R, Scarpini C. (1990) Electroenceph. cl. Neurophysiol.75: 56--63.
•1
LUMBOSACRAL MOTOR ROOT CONDUCTION WITH PERCUTANEOUS ELECTRICAL STIMULATION IN INTERMITTENT NEUROGENIC CLAUDICATION
J. Barios, M. Hijosa, A. Tmba, A. Esteban. Clinical Neurophysiology
Section, Hospital G.U. Gregorio Mara~dn, Madrid, Spain Lumbosacral motor root conduction (LMRC) permits the study of the proximal motor segments of cauda equina. Ten patients who showed clinical symptoms of intermittent neurogenic claudication (INC) and 18 matched normal subjects as control group, were selected. Conventional EMG and LMRC were performed on all of them. It was carried out by means of a percutaneous short duration high voltage bipolar stimulation, with the cathode placed on 3 raquideous spinous levels (L1, L3, L5), and the anode placed proximally. Simultaneous surface recordings were performed on the tibialis anterior and soleus muscles bilaterally. Each subject was examined on ventral decubitus position and after 15 minutes standing. On the conventional EMG study 5 showed denervation activity, 4 had chronic neurogenic changes and 1 normal findings, During examination in decubitus position 9 patients revealed some LMRC disturbances: partial conduction blocks or conduction slowing in any of the three stimulation levels. While standing, 8 patients including the normal one on decubitus, showed worsening of conduction; in 4 of which appearing clinical symptoms. After surgery, 3 patients showed LMRC improving. LMRC is a feasible and sensitive method for evaluation of the INC and should be considered as a complementary technique. Moreover, examination in standing position allows to evaluate ~'ansient neurophysiological modifications following postural changes. ~-1-~
THE UTILITY OF ELECTRODIAGNOSIS IN SINGLE C71C8 RADICULOPATHIES: A DISTAL APPROACH
I.K. Ibrahim. Faculty of Medicine, Alexandria, Egypt The sensory-motor dissociation of the median nerve fibres in the hand with C6-C7 dermatomal and C8-TI myotomal distribution was utilised to assess single C7 and single C8 radiculopathies and to differentiate
carpal tunnel syndrome (CTS) and ulnar nerve compression (UNC) respectively. Conventional sensory and motor conduction of the median and ulnar nerves as well as dermatomal somatosensory evoked potentials were studied in 15 patients with single C7 radiculopathy, 10 patients with single C8 radiculopathy, 25 patients with CTS and 7 patients with UNC at elbow. In patients with single C8 radiculopathy, the median nerve conduction study showed normal latency but low amplitude of the motor potential recorded on the abductor pollicis brevis muscle associated with normal sensory latency and amplitude. On the other hand, the ulnar nerve showed normal motor latency and amplitude associated with low amplitude - but normal latency- of the sensory potential recorded on digit V. In patients with single C7 radiculopathy, the median nerve showed normal motor response associated with low amplitude - but normal latency- of the sensory potentials recorded on digit II and III. The ulnar nerve showed normal motor and sensory responses.
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ELECTRONEUROGRAPHIC (ENOG) EVALUATION OF PERIPHERAL FACIAL PALSY (PFP). EARLY AND LATE RESULTS IN 500 PATIENTS
Jose M. Fernandez ~, Julio Pardo 2, Susana Mederer i, Jordi Battle 3
l Hospital Xeral-Cies, Vigo, Spain; 2 Hospital General, Santiago, Spain; 3 Hospital Sta Magdalena, Tarragona, Spain Background: Facial ENoG is a rapid and non-invasive test widely used in the early prognosis of PFP. However, it has been less often used in assessing nerve regeneration and the long term results. Patients and Methods: Amplitude and Area of the Compound Muscle Action Potentials (CMAPs) of the orbicularis oris were obtained on both normal and paretic sides. ENoG was expressed as a percentage in side-to-side comparison. Surface electrodes were used for stimulation and recording. ENoG examination was performed on all patients on day 10 to 15 and again on day 30 after onset. One hundred and fifty patients were also examined on day 4 to 6. Patients with severe axonotmesis (> 80%) were followed-up for 2 years. Clinical status was assessed following Zander Olsen score. Results: On days 10 to 15, ENoG of 50% or higher predicted a complete recovery within 4-8 weeks. Patients with ENoG values between 50% and 25% recover within 6 months with mild or no sequelae. ENoG values between 25% and 10% implied a delayed recovery (6--9 months) with mild to moderate sequelae. ENoG values less than 10% resulted always in a slow recovery (12 months or more) and severe sequelae. Two years after onset even patients with early low ENoG values (10% or less) had amplitudes higher than 50%. Conclusions: ENoG is a very sensitive prognostic test for PFF. In patients with severe sequelae, ENoG higher than 50% 2 years after onset suggest that poor recovery is due to aberrant rather than faulty reinnervation.
RETEST RELIABILITY IN FACIAL NERVE CONDUCTION STUDIES O. Guntinas-Lichius, C. Sittel, E. Stennert. Cologne University, Germany
Background: Facial nerve conduction studies (Electroneurography [ENG] or Magnetic stimulation [MAG]) are established tools for monitoring facial nerve palsies. Repeated testing of compound muscle action potential (CMAP) and latencies is believed to show conduction loss with or without ongoing axonal degeneration. Up to now there are no convincing studies that these measurements are sufficiently constant in the healthy subject. Study design: 20 healthy adult volunteers (m = 12, f = 8, age 23-35 y) without prior facial nerve pathology were tested four times with intervals of one week. Left and right facial nerve were examined by ENG and by cisternal MAG. Latency, and CMAP were measured. Left-right differences were calculated and analysed by descriptive statistics, and Levene's test for homogeneity of variance. A retest reliability analysis for Cronbach's Alpha was performed. Results: ENG: Latency difference was 0.39 5= 0.32 (mean -t- SD), var = 0.1 (mean variance), Levene p = 0.94, retest reliability a = 0.2. Amplitude difference was 0.74 4- 0.57, var = 0.33, Levene p = 0.14, a = 0.04. MAG: Latency difference was 0.51 + 1.13 (mean 4- SD), vat = 1.25, Levene p = 0.04, a = 0.01. Amplitude difference was 0.90 4- 0.65, var = 0.41, Levene p = 0.52, c~ = 0.47.
Poster Session: Electromyography and Neurography H-REFLEXES IN CHRONIC LOW BACK PAIN
R. Mazzocchio, A. Bolognini, A. Mariottini, V.E Muzii, L. Palma, G. Rizzo, G.B. Scarfo'. Cattedra di Neurochirurgia, Universita' di Siena,
Italy The afferent limb of the Soleus H-reflex is very sensitive to the effects of peripheral nerve ischemic compression [1]. By analogy, it could be susceptible to the effects of repeated compression on lumbosacral nerve roots caused by intermittent narrowing of the vertebral canal due to segmental instability. We examined 15 patients (mean age 55, range 34-76) affected by chronic low back pain with radiologic evidence of isthmic spondylolisthesis, mostly at L4-L5 level. Pain was aggravated by standing, mechanical loads and poor posture. None of the patients had clinical or electrophysiological signs of peripheral nerve disfunction. Soleus H-reflexes were considered abnormal if the latency was above 2 SD from the mean of height-matched controls, if there was a side-to-side difference of more than 2 ms, or if the response was absent. In 7 out of 15 patients, H-reflexes were normal. In the remaining eight, the whole range of abnormalities was found: a) a side-to-side latency difference in three, b) a bilateral latency increase in two, c) a unilateral latency increase and lack of response in one, and d) a bilateral lack of response in two subjects. In these patients, low back pain was often associated with diffuse leg pain on standing; all but one had segmental instability above L5-S1 level, and H-reflexes abnormalities were mainly bilateral. This data rather than indicate an individual radiculopathy may be interpreted as a sign of chronic, symmetric constriction of the thecal sac with root injury occurring in the vertebral canal rather than in the respective neural foramina. S1 dorsal roots may be particularly liable to ischaemia and mechanical irritation because of their large size and long course in the spinal canal. We propose that soleus H-reflex testing may help detect early signs of multiple root injury in chronic low back pain due to segmental instability. Reference
[1] Rossi A, Mazzocchio R, Scarpini C. (1990) Electroenceph. cl. Neurophysiol.75: 56--63.
•1
LUMBOSACRAL MOTOR ROOT CONDUCTION WITH PERCUTANEOUS ELECTRICAL STIMULATION IN INTERMITTENT NEUROGENIC CLAUDICATION
J. Barios, M. Hijosa, A. Tmba, A. Esteban. Clinical Neurophysiology
Section, Hospital G.U. Gregorio Mara~dn, Madrid, Spain Lumbosacral motor root conduction (LMRC) permits the study of the proximal motor segments of cauda equina. Ten patients who showed clinical symptoms of intermittent neurogenic claudication (INC) and 18 matched normal subjects as control group, were selected. Conventional EMG and LMRC were performed on all of them. It was carried out by means of a percutaneous short duration high voltage bipolar stimulation, with the cathode placed on 3 raquideous spinous levels (L1, L3, L5), and the anode placed proximally. Simultaneous surface recordings were performed on the tibialis anterior and soleus muscles bilaterally. Each subject was examined on ventral decubitus position and after 15 minutes standing. On the conventional EMG study 5 showed denervation activity, 4 had chronic neurogenic changes and 1 normal findings, During examination in decubitus position 9 patients revealed some LMRC disturbances: partial conduction blocks or conduction slowing in any of the three stimulation levels. While standing, 8 patients including the normal one on decubitus, showed worsening of conduction; in 4 of which appearing clinical symptoms. After surgery, 3 patients showed LMRC improving. LMRC is a feasible and sensitive method for evaluation of the INC and should be considered as a complementary technique. Moreover, examination in standing position allows to evaluate ~'ansient neurophysiological modifications following postural changes. ~-1-~
THE UTILITY OF ELECTRODIAGNOSIS IN SINGLE C71C8 RADICULOPATHIES: A DISTAL APPROACH
I.K. Ibrahim. Faculty of Medicine, Alexandria, Egypt The sensory-motor dissociation of the median nerve fibres in the hand with C6-C7 dermatomal and C8-TI myotomal distribution was utilised to assess single C7 and single C8 radiculopathies and to differentiate
carpal tunnel syndrome (CTS) and ulnar nerve compression (UNC) respectively. Conventional sensory and motor conduction of the median and ulnar nerves as well as dermatomal somatosensory evoked potentials were studied in 15 patients with single C7 radiculopathy, 10 patients with single C8 radiculopathy, 25 patients with CTS and 7 patients with UNC at elbow. In patients with single C8 radiculopathy, the median nerve conduction study showed normal latency but low amplitude of the motor potential recorded on the abductor pollicis brevis muscle associated with normal sensory latency and amplitude. On the other hand, the ulnar nerve showed normal motor latency and amplitude associated with low amplitude - but normal latency- of the sensory potential recorded on digit V. In patients with single C7 radiculopathy, the median nerve showed normal motor response associated with low amplitude - but normal latency- of the sensory potentials recorded on digit II and III. The ulnar nerve showed normal motor and sensory responses.
•3•
ELECTRONEUROGRAPHIC (ENOG) EVALUATION OF PERIPHERAL FACIAL PALSY (PFP). EARLY AND LATE RESULTS IN 500 PATIENTS
Jose M. Fernandez ~, Julio Pardo 2, Susana Mederer i, Jordi Battle 3
l Hospital Xeral-Cies, Vigo, Spain; 2 Hospital General, Santiago, Spain; 3 Hospital Sta Magdalena, Tarragona, Spain Background: Facial ENoG is a rapid and non-invasive test widely used in the early prognosis of PFP. However, it has been less often used in assessing nerve regeneration and the long term results. Patients and Methods: Amplitude and Area of the Compound Muscle Action Potentials (CMAPs) of the orbicularis oris were obtained on both normal and paretic sides. ENoG was expressed as a percentage in side-to-side comparison. Surface electrodes were used for stimulation and recording. ENoG examination was performed on all patients on day 10 to 15 and again on day 30 after onset. One hundred and fifty patients were also examined on day 4 to 6. Patients with severe axonotmesis (> 80%) were followed-up for 2 years. Clinical status was assessed following Zander Olsen score. Results: On days 10 to 15, ENoG of 50% or higher predicted a complete recovery within 4-8 weeks. Patients with ENoG values between 50% and 25% recover within 6 months with mild or no sequelae. ENoG values between 25% and 10% implied a delayed recovery (6--9 months) with mild to moderate sequelae. ENoG values less than 10% resulted always in a slow recovery (12 months or more) and severe sequelae. Two years after onset even patients with early low ENoG values (10% or less) had amplitudes higher than 50%. Conclusions: ENoG is a very sensitive prognostic test for PFF. In patients with severe sequelae, ENoG higher than 50% 2 years after onset suggest that poor recovery is due to aberrant rather than faulty reinnervation.
RETEST RELIABILITY IN FACIAL NERVE CONDUCTION STUDIES O. Guntinas-Lichius, C. Sittel, E. Stennert. Cologne University, Germany
Background: Facial nerve conduction studies (Electroneurography [ENG] or Magnetic stimulation [MAG]) are established tools for monitoring facial nerve palsies. Repeated testing of compound muscle action potential (CMAP) and latencies is believed to show conduction loss with or without ongoing axonal degeneration. Up to now there are no convincing studies that these measurements are sufficiently constant in the healthy subject. Study design: 20 healthy adult volunteers (m = 12, f = 8, age 23-35 y) without prior facial nerve pathology were tested four times with intervals of one week. Left and right facial nerve were examined by ENG and by cisternal MAG. Latency, and CMAP were measured. Left-right differences were calculated and analysed by descriptive statistics, and Levene's test for homogeneity of variance. A retest reliability analysis for Cronbach's Alpha was performed. Results: ENG: Latency difference was 0.39 5= 0.32 (mean -t- SD), var = 0.1 (mean variance), Levene p = 0.94, retest reliability a = 0.2. Amplitude difference was 0.74 4- 0.57, var = 0.33, Levene p = 0.14, a = 0.04. MAG: Latency difference was 0.51 + 1.13 (mean 4- SD), vat = 1.25, Levene p = 0.04, a = 0.01. Amplitude difference was 0.90 4- 0.65, var = 0.41, Levene p = 0.52, c~ = 0.47.