Serial visual evoked potentials in 90 untreated patients with acute optic neuritis.

To establish the value of visual evoked potentials (VEPs) for monitoring disease evolution, we undertook a population-based study of 90 untreated patients 12 to 57 years of age (median, 32 years) at the onset of optic neuritis (ON) and after 2, 4, 12, and 52 weeks. Optic neuritis was monosymptomatic (AMON) in 58 patients and part of the clinically definite multiple sclerosis (CDMS) in 32 patients. The VEP was abnormal in eyes with acute ON in 69 (77%) of 90 patients at onset and in 80 (89%) of 90 patients at one or more of the follow-up sessions. In eyes with acute ON, normalization of an initially abnormal VEP was observed during 1-year follow-up in 13 (19%) of 69 patients. At onset of ON, VEP was abnormal in 35% of the clinically unaffected eyes. By parametric analysis of variance, the latencies (P = 0.0058), the amplitudes (P = 0.0298), and the combined VEP scores (P = 0.0345) in the eyes with acute ON were significantly associated with the time after onset. The latencies were influenced by the presence of CDMS (P = 0.0033), whereas the amplitudes were influenced by visual acuity (P = 0.0000). When visual acuity was included in a multifactor model, the time after onset was, however, not significantly associated with the amplitude (P = 0.8826). The mean latency of the VEPs in eyes with acute ON was significantly shorter in AMON than in ON as part of CDMS. This study provides evidence that VEP abnormality is often transitory, and that VEP often normalizes during follow-up. The diagnostic yield is increased by repeating VEP in the spontaneous course of acute ON. Visual evoked potential is a sensitive tool for revealing subclinical lesions.

Serial MRI, VEP, SEP and biotesiometry in acute optic neuritis: value of baseline results to predict the development of new lesions at one year follow up.

INTRODUCTION: In an attempt to establish the value of MRI, VEP, SEP, and biotesiometry in monitoring disease evolution we undertook a one year follow up study of 70 untreated patients with acute optic neuritis (ON). MATERIAL & METHODS: ON was monosymptomatic in 48 patients (bilateral in 10) and part of clinically definite multiple sclerosis (CDMS) in 22 patients, examined as mentioned below. RESULTS: Results are given at onset and at follow up (in brackets). In monosymptomatic ON, brain MRI was abnormal in 53% (53%), VEP in the eye with acute ON in 79% (71%), VEP in the clinically unaffected eye in 34% (47%), SEP in 25% (23%), and biotesiometry in 29% (17%). In CDMS, brain MRI was abnormal in 95% (95%), VEP in the eye with acute ON in 86% (77%), VEP in the clinically unaffected eye in 50% (64%), SEP in 55% (50%), and biotesiometry in 63% (53%). Only minor changes in test scores were observed after one year except for significant improvement of VEP in eyes with acute ON. Eight of 32 patients, characterized by at least one abnormal paraclinical test at onset of monosymptomatic ON, had developed CDMS versus none of 16 patients with normal paraclinical results (p = 0.03; Fisher). CONCLUSION: Patients with monosymptomatic ON with paraclinical signs of multifocal involvement at onset had an increased risk of developing CDMS. No single test predicted the evolution of CDMS, perhaps due to the relatively short follow up time.

Acute unilateral papillitis versus retrobulbar neuritis: relation to multiple sclerosis.

Prospectively referred patients with unilateral acute optic neuritis (ON) (n = 223; aged 12-57; 158 women), either idiopathic or part of clinically definite multiple sclerosis (CDMS), were systematically examined by the same physician. We analysed whether the 161 patients with retrobulbar neuritis and the 62 patients with papillitis differed from each other clinically or according to paraclinical tests. The following characteristics were observed in retrobulbar ON respectively papillitis: median age 33 and 33 years, women 70% and 73%, clinically definite MS 30% and 27%. Abnormal results in retrobulbar ON and in papillitis (indicated in brackets) did not differ significantly and were found as follows: cerebral MRI in 56% (63%), VEP from the eye with acute ON in 82% (88%), VEP from the eye without acute ON in 38% (33%), SEP from median nerves in 9% (10%), SEP from tibial nerves in 22% (22%) and biotesiometry in 32% (27%). In the CSF, oligoclonal bands were present in 42% (53%), increased IgG-index in 40% (44%) and increased leucocyte count in 39% (29%). The HLA-DRI5 tissue type was present in 47% (43%). There were no significant differences between retrobulbar ON and papillitis when the idiopathic cases and cases with clinically definite MS were analysed separately. Our data document that unilateral retrobulbar ON and papillitis are both part of the MS spectrum and not different from each other with regard to clinical and paraclinical parameters, indicating that the two groups can be pooled in future treatment trials.

KANDID--an EMG decision support system--evaluated in a European multicenter trial.

KANDID is an advanced EMG decision support system dedicated to the support of the clinical neurophysiologist during EMG examinations. It has facilities for test planning, automatized and structured data interpretation, EMG diagnosis, explanation, and reporting. In a prospective European multicenter field trial, the agreement levels between clinical neurophysiologists and KANDID's diagnostic statements were measured under ordinary clinical EMG practice. KANDID was assessed in 159 individual patient EMG examinations by nine clinical neurophysiologists at seven different EMG laboratories. The reasoning of KANDID was considered understandable for the examiners in 80-90% of cases. The agreement level for the electrophysiological states of muscles and nerves between KANDID and the individual examiners was, on average, 81%. The corresponding diagnostic agreement with KANDID was, on average, 61%. A pronounced interexaminer variation in the agreement level related to the different EMG centers was observed. All Danish and Belgian examiners agreed with KANDID in more than 50% of their cases with regard to the EMG diagnosis, while the English examiners were in agreement with KANDID in 50% or less of their cases. These differences were possibly due to differences in epidemiology, examination techniques, control material, and examination planning strategies. It is concluded that it is possible to transfer systems like KANDID out of their development sites and apply them successfully if they can be locally customized by the clinical end users via editors.

Serial pattern evoked potential recording in a case of toxic optic neuropathy due to ethambutol.

Visual evoked potentials (VEPs) were studied in a patient who developed visual impairment during ethambutol treatment. The ERG and the flash VEP were normal at the time of maximal visual loss, whereas pattern reversal VEPs 2 and 5 months after onset revealed evidence of severe bilateral optic nerve involvement, especially affecting macular fibres. Seven months after onset paramacular PNP complexes with a late positivity (scotomatous response) were recorded after pattern reversal and half-field stimulation, suggesting involvement of fibres subserving central vision. At the time when visual acuity was normal there was still electrophysiological evidence of a mild involvement of the anterior visual pathway. The papillomacular bundle seems to be especially involved in ethambutol eye toxicity.

Electrophysiological study of the peripheral and central neurotoxic effect of cis-platin.

We describe clinical and electrophysiological findings in 8 patients with tumors of germ cell origin before and after treatment with high-dose cisplatin (800-1400 mg) combined with etoposide and bleomycin. All patients developed clinical or electrophysiological signs, or both, of a peripheral sensory neuropathy. One had in addition clinical and electrophysiological signs of CNS involvement, and 2 had a central conduction defect revealed by auditory stimulation.

Ocular ethambutol toxicity. A case report with electrophysiological considerations and a review of Danish cases 1972-81.

A 76-year-old female with ocular ethambutol toxicity prompted two investigations. Firstly, she was followed electrophysiologically, with multichannel recorded pattern reversal visual evoked potential techniques using full-field, half-field, central-field and peripheral field stimulation, plus flash VEP and ERG. The examinations performed 2, 5 and 7 months after ethambutol withdrawal indicated damage to the papillomacular bundle, while a late follow-up after recovery showed potentials of near normal configuration. Secondly an epidemiological survey was attempted based on the 37 ethambutol toxicity cases registered to the Danish Board on Adverse Reactions 1972-81, making up 1% of those receiving antituberculous therapy. They showed a significant preponderance of elderly (24/37 greater than 65 years) and of females (29/37). There was only one foreigner in the series. A detailed analysis of visual function in a subsample of 22 cases (those registered 1977-81) showed that visual impairment lasted several months, and that usually recovery was not complete. Using the visual demands for driver's license as criterium, 20 fulfilled the demands prior to therapy, but only 12 after recovery.

Conduction studies of the long thoracic nerve in serratus anterior palsy of different etiology.

We studied nerve conduction in 24 patients with serratus anterior palsy of different etiology. On the unaffected control side, the latency of the evoked motor responses after stimulation of the long thoracic nerve in the supraclavicular fossa increased 0.2 msec per 10-mm increase in conduction distance, corresponding to a velocity of 67m-s. The method was valuable in determining whether the lesion was partial or complete and in revealing regeneration after wallerian degeneration.

Conduction studies along the accessory nerve and follow-up of patients with trapezius palsy.

The accessory nerve was stimulated at the posterior triangle of the neck and responses were evoked simultaneously from the upper, middle and lower part of the trapezius muscle. Sixteen patients were investigated, 10 with trapezius palsy following surgical procedures at the posterior cervical triangle, three with a history suggestive of neuralgic amyotrophy and three of unknown origin. On the unaffected side the latency increases 0.16 ms per 10 mm increase in conduction distance corresponding to a conduction velocity of 63 m/s. Evidence is presented that the upper, middle and lower part of the trapezius muscle receive innervation from the accessory nerve. Follow-up of patients showed spontaneous nerve regeneration after complete axonal degeneration. These findings suggest that surgical intervention should be delayed to allow for spontaneous reinnervation. Clinical recovery was incomplete in cases of iatrogenic origin.

A case of malignant lymphoma and myasthenia gravis.

A 25-year-old man with myasthenia gravis and a non-Hodgkin lymphoma stage III B involving the thymus, is reported. The association myasthenia gravis and non-Hodgkin lymphoma has not been described previously. Treatment with chlormetin, vincristine, procarbazine, prednisone (MOPP) resulted in complete remission of both the myasthenic symptoms and the malignant lymphoma.