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Contribution of electrophysiological examinations to the differential diagnosis of facial palsies
ELSEVIER
Electroencephalography and clinical Neurophysiology 95 (1995) 4P-8P
Society proceedings
Swiss Society of Clinical Neurophysiology Merligen/Thunersee,
Secretary:
Switzerland, 2-4 June 1994
Dr. Walter G. Friedli
Bethesda Spital, Gellertstrasse 144, 4020 Basel, Switzerland Received for publication: 9 March 1995
1. Task-dependent facilitation of motor evoked potentials (MEP). J. Mathis, DJ.-F. De Quervain and Ch.W. Hess (Bern) Voluntary muscle contraction has an important and well known facilitatory effect onto transcranial magnetic MEPs. We studied this facilitation during a maintain-force and during a maintain-position task of the biceps brachii muscle under identical force levels. The quotient of MEP amplitude/background EMG (gain) was greater during the maintain-force task than during the maintain-position task ( P < 0.001) indicating a task-dependent facilitation of the MEP amplitude. At low stimulus intensities the postexcitatory silent period (SP) was significantly ( P < 0.001) shorter in the isometric maintain-force trials than in the maintain-position trials where a shortening of the muscle after the stimulus was possible. The duration of the muscle shortening in the maintain-position task outlasted the SP. Thus, the increased SP in the maintain-position task could be due to a pause in muscle spindle activity, occurring in a shortening muscle. On the contrary, at high stimulus intensities no difference between the SPs was observed. However, under these conditions the duration of the muscle shortening was shorter than the duration of the SP, and therefore an influence of the spindle pause could not be expected. Thus, the SP at high stimulus intensities was more likely due to a central inhibitory effect. 2. Bilateral peripheral facial paralysis and HIV infection. - A. Kohler, M.R. Magistris and R. Sztajzel (Geneva) Peripheral facial palsies are well known in HIV infection. They may occur at any stage of the disease, including at the time of seroconversion; they are sometimes the first manifestation of the infection. Only few cases of bilateral facial palsy are reported, rarely isolated. We report the history of a 43-year-old woman, in good health, who developed over a period of 3 days a bilateral facial paralysis, without taste impairment. The neurological status was otherwise normal. She had some cervical and axillary adenopathies. Electroneuromyography showed an almost complete bilateral facial nerve lesion, of axonotmesis type. Serology was positive for HIV, negative for Lyme disease. The CD4 count was 404. CSF was abnormal, with a mild non-specific infiammatory reaction (protein 0.64 g / l , 7 cells/mm3). Cerebral magnetic resonance was normal. Such an isolated facial diplegia is an extremely unusual presentation, different of the common causes of facial paralysis. We believe it was the first manifestation of the stage 3 HIV infection in our patient. We conclude that HIV infection should be considered in the differential diagnosis of both uni- and bilateral facial palsies.
3. Contribution of electrophysiological examinations to the differential diagnosis of facial palsies. - K.M. R6sler, M.R. Magistris, F.X. GIocker and C.W. Hess (Bern, Geneva, Freiburg i. Brsg.) Electrophysiological studies of facial motor pathways were performed in 145 patients with facial palsies of various aetiologies (77 Bell's palsies, 21 Guillain-Barr6 syndromes (GBS), 18 Lyme Borreliosis, 12 zoster oticus, 9 meningeal affections and 8 brain-stem disorders). The facial nerve was stimulated electrically at the stylomastoid fossa and magnetically at its entrance into the facial canal. The face-associated motor cortex was stimulated magnetically. Recordings were made from the nasalis or mentalis muscle using surface electrodes. Bilateral examinations were performed throughout. Conduction disorders were localized and characterized using conventional neurographic criteria. In Bell's palsy, GBS and Lyme disease, the conduction disorder was most often localized to the facial canal. In Bell's palsy, it was typically unilateral, with a local hypoexcitability of the facial nerve to canalicular stimulation. Conversely, in GBS and Lyme disease, a high percentage of subclinical contralateral affections were detected. In addition, GBS usually led to prolonged conduction times. In zoster oticus, highly axonal nerve lesions (that could not be localized) were typical. Finally, in brain-stem disease, the conduction disorder could correctly be localized by cortex stimulation. We conclude that these inexpensive and non-invasive electrophysiological techniques may contribute to the clinical differential diagnosis of facial palsies. 4. Usefulness of longitudinal nerve conduction studies: example in a Refsum's disease patient. - T. Kuntzer, F. Ochsner, F. Schmid and F. Regli (Lausanne) A patient with anosmia and night blindness had repeated clinical and electrophysiological examinations during a 21 year period. Within the first 11 years, he experienced two subacute episodes of numbness with weakness and ataxia. Over the 10 ensuing years, no additional functional disability appeared. We looked for a correlation between repeated manual muscle scoring and different nerve conduction parameters. Further studies were done in order to estimate reinnervation and to assess autonomic functions. A direct relationship was found between the magnitude of muscle weakness and the amplitude of compound muscle action potentials whereas nerve conduction velocities were inhomogencously reduced but almost unchanged over time. Parasympathetic tests were normal but sympathetic skin responses were absent. As estimated by macro-EMG and turns-amplitude analysis the compensatory reinnervation was high. We conclude that in Refsum's disease recurrent segmental demyelination of a significant portion of the motor units can occur in parallel with
0013-4694/95/$09.50 © 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0 0 1 3 - 4 6 9 4 ( 9 5 ) 0 0 0 6 0 - 7
EEG 95543
Electroencephalography and clinical Neurophysiology 95 (1995) 4P-8P
Society proceedings
Swiss Society of Clinical Neurophysiology Merligen/Thunersee,
Secretary:
Switzerland, 2-4 June 1994
Dr. Walter G. Friedli
Bethesda Spital, Gellertstrasse 144, 4020 Basel, Switzerland Received for publication: 9 March 1995
1. Task-dependent facilitation of motor evoked potentials (MEP). J. Mathis, DJ.-F. De Quervain and Ch.W. Hess (Bern) Voluntary muscle contraction has an important and well known facilitatory effect onto transcranial magnetic MEPs. We studied this facilitation during a maintain-force and during a maintain-position task of the biceps brachii muscle under identical force levels. The quotient of MEP amplitude/background EMG (gain) was greater during the maintain-force task than during the maintain-position task ( P < 0.001) indicating a task-dependent facilitation of the MEP amplitude. At low stimulus intensities the postexcitatory silent period (SP) was significantly ( P < 0.001) shorter in the isometric maintain-force trials than in the maintain-position trials where a shortening of the muscle after the stimulus was possible. The duration of the muscle shortening in the maintain-position task outlasted the SP. Thus, the increased SP in the maintain-position task could be due to a pause in muscle spindle activity, occurring in a shortening muscle. On the contrary, at high stimulus intensities no difference between the SPs was observed. However, under these conditions the duration of the muscle shortening was shorter than the duration of the SP, and therefore an influence of the spindle pause could not be expected. Thus, the SP at high stimulus intensities was more likely due to a central inhibitory effect. 2. Bilateral peripheral facial paralysis and HIV infection. - A. Kohler, M.R. Magistris and R. Sztajzel (Geneva) Peripheral facial palsies are well known in HIV infection. They may occur at any stage of the disease, including at the time of seroconversion; they are sometimes the first manifestation of the infection. Only few cases of bilateral facial palsy are reported, rarely isolated. We report the history of a 43-year-old woman, in good health, who developed over a period of 3 days a bilateral facial paralysis, without taste impairment. The neurological status was otherwise normal. She had some cervical and axillary adenopathies. Electroneuromyography showed an almost complete bilateral facial nerve lesion, of axonotmesis type. Serology was positive for HIV, negative for Lyme disease. The CD4 count was 404. CSF was abnormal, with a mild non-specific infiammatory reaction (protein 0.64 g / l , 7 cells/mm3). Cerebral magnetic resonance was normal. Such an isolated facial diplegia is an extremely unusual presentation, different of the common causes of facial paralysis. We believe it was the first manifestation of the stage 3 HIV infection in our patient. We conclude that HIV infection should be considered in the differential diagnosis of both uni- and bilateral facial palsies.
3. Contribution of electrophysiological examinations to the differential diagnosis of facial palsies. - K.M. R6sler, M.R. Magistris, F.X. GIocker and C.W. Hess (Bern, Geneva, Freiburg i. Brsg.) Electrophysiological studies of facial motor pathways were performed in 145 patients with facial palsies of various aetiologies (77 Bell's palsies, 21 Guillain-Barr6 syndromes (GBS), 18 Lyme Borreliosis, 12 zoster oticus, 9 meningeal affections and 8 brain-stem disorders). The facial nerve was stimulated electrically at the stylomastoid fossa and magnetically at its entrance into the facial canal. The face-associated motor cortex was stimulated magnetically. Recordings were made from the nasalis or mentalis muscle using surface electrodes. Bilateral examinations were performed throughout. Conduction disorders were localized and characterized using conventional neurographic criteria. In Bell's palsy, GBS and Lyme disease, the conduction disorder was most often localized to the facial canal. In Bell's palsy, it was typically unilateral, with a local hypoexcitability of the facial nerve to canalicular stimulation. Conversely, in GBS and Lyme disease, a high percentage of subclinical contralateral affections were detected. In addition, GBS usually led to prolonged conduction times. In zoster oticus, highly axonal nerve lesions (that could not be localized) were typical. Finally, in brain-stem disease, the conduction disorder could correctly be localized by cortex stimulation. We conclude that these inexpensive and non-invasive electrophysiological techniques may contribute to the clinical differential diagnosis of facial palsies. 4. Usefulness of longitudinal nerve conduction studies: example in a Refsum's disease patient. - T. Kuntzer, F. Ochsner, F. Schmid and F. Regli (Lausanne) A patient with anosmia and night blindness had repeated clinical and electrophysiological examinations during a 21 year period. Within the first 11 years, he experienced two subacute episodes of numbness with weakness and ataxia. Over the 10 ensuing years, no additional functional disability appeared. We looked for a correlation between repeated manual muscle scoring and different nerve conduction parameters. Further studies were done in order to estimate reinnervation and to assess autonomic functions. A direct relationship was found between the magnitude of muscle weakness and the amplitude of compound muscle action potentials whereas nerve conduction velocities were inhomogencously reduced but almost unchanged over time. Parasympathetic tests were normal but sympathetic skin responses were absent. As estimated by macro-EMG and turns-amplitude analysis the compensatory reinnervation was high. We conclude that in Refsum's disease recurrent segmental demyelination of a significant portion of the motor units can occur in parallel with
0013-4694/95/$09.50 © 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0 0 1 3 - 4 6 9 4 ( 9 5 ) 0 0 0 6 0 - 7
EEG 95543