Dag Hydén

Otoneurological Findings in Psycho-organic Syndrome Caused by Industrial Solvent Exposure

Nine subjects with long-term (8-30 years) occupational exposure to industrial solvents and a confirmed diagnosis of psycho-organic syndrome (POS) have been studied with audiological and otoneurological test batteries. The results were compared to a matched control group of nine industrial workers not exposed to solvents and to normal data from healthy volunteers. In the clinical examination, the Romberg test identified 5/9 workers as pathologic and concurrently the stabilometry showed significantly larger sway areas in the POS-group. In the audiological test battery, the significantly pathologic tests were discrimination of interrupted speech and evoked cortical responses to frequency glides (CRA-delta-f). The saccade test disclosed abnormal findings in 5/9 workers. In the smooth pursuit test, abnormality was found at some test frequencies using pseudorandomized stimulus. The VOR-suppression test was significantly abnormal at all test frequencies. The test battery used strongly indicates CNS lesions due to industrial solvents.

Acute peripheral facial palsy: CSF findings and etiology

CSF and serum were examined in acute and convalescence phase from 56 patients with acute idiopathic peripheral facial palsy. CSF protein analysis, viral and borrelia serology were performed. Borrelia infection was found in 9/56 cases and was often associated with inflammatory CSF findings. One patient each had serological evidence for a recent or ongoing infection with herpes simplex, varicella zoster, adeno, influenza B, echo and Epstein‐Barr virus, but none had specific intrathecal antibody synthesis; 11 patients had a serological pattern compatible with a reactivated Epstein‐Barr virus infection. Eleven patients displayed mononuclear CSF pleocytosis. Four of them had a borrelia infection. A disturbed blood‐brain barrier was observed in 19 patients. Intrathecal immunoglobulin synthesis as indicated by elevated IgM‐indices was found in 16 patients and by IgG indices in three. Nine patients had oligoclonal IgG bands in serum and CSF, three exclusively in CSF. It is concluded that patients with facial palsy often have inflammatory CSF findings, indicating a generalised central nervous system affection, and not only a mononeuritis. The importance of viral infections in the pathogenesis is still obscure. Borrelia is the most common infectious cause of facial palsy.

Inner ear and facial nerve complications of acute otitis media with focus on bacteriology and virology

Conclusion. Among 20 patients with inner ear complications and/or peripheral facial palsy secondary to acute otitis media (AOM) a proven or probable bacteriological cause was found in 13 (65%). In seven patients (35%), a proven or probable viral cause was found. Only two of the patients (10%), with a proven bacterial AOM and a clinical picture of a purulent labyrinthitis in both, together with a facial palsy in one, had a substantial degree of dysfunction. Although the number of patients in this study is relatively low our findings show that inner ear complications and facial palsy due to AOM can be of both bacterial and viral origin. Severe sequelae were found only where a bacterial origin was proven. Objectives. Inner ear complications and/or peripheral facial palsy secondary to AOM are rare. The general understanding is that they are due to bacterial infections. However, in some of these patients there are no clinical or laboratory signs of bacterial infections and they have negative bacterial cultures. During recent years different viruses have been isolated from the middle ear or serologically proven in AOM patients and are thought to play a pathogenetic role. We suggest that in some cases of AOM complications from the inner ear and the facial nerve can be caused by viruses. The purpose of our study was to analyze infectious agents present in patients with inner ear complications and/or facial palsy arising from AOM. Patients and methods. The medical records of 20 patients who had inner ear complications and/or facial palsy following AOM ( unilateral in 18, bilateral in 2) between January 1989 and March 2003 were evaluated. Bacterial cultures were carried out for all patients. Sera from 12 of the patients were stored and tested for a battery of specific viral antibodies. In three patients, investigated between November 2002 and March 2003, viral cultures were also performed on samples from the middle ear and nasopharynx. Results. Nineteen patients had inner ear symptoms. Eight of them had a unilateral sensorineural hearing loss and vertigo, three had vertigo as an isolated symptom and one, with bilateral AOM, had bilateral sensorineural hearing loss. Seven patients had a combination of facial palsy and inner ear symptoms (unilateral sensorineural hearing loss in three, unilateral sensorineural hearing loss and vertigo in two, bilateral sensorineural hearing loss and vertigo in one, with bilateral AOM, and vertigo alone in one). One patient had an isolated facial palsy. Healing was complete in 11 of the 20 patients. In seven patients a minor defect remained at follow-up (a sensorineural hearing loss at higher frequencies in all). Only two patients had obvious defects (a pronounced hearing loss in combination with a moderate to severe facial palsy (House-Brackman grade 4) in one, distinct vestibular symptoms and a total caloric loss in combination with a high-frequency loss in the other. Eight patients had positive bacteriological cultures from middle ear contents: Streptococcus pneumoniae in two, beta-hemolytic Streptococcus group A in two, beta-hemolytic Streptococcus group A together with Staphylococcus aureus in one, Staph. aureus alone in one and coagulase-negative staphylococci (interpreted as pathogens) in two. In the 12 patients with negative cultures, there was a probable bacteriological cause due to the outcome in SR/CRP and leukocyte count in five. In four patients serological testing showed a concomitant viral infection that was interpreted to be the cause (varicella zoster virus in two, herpes simplex virus in one and adenovirus in one.) In three there was a probable viral cause despite negative viral antibody test due to normal outcome in SR/CRP, normal leukocyte count, serous fluid at myringotomy and a relatively short pre-complication antibiotic treatment period.

Acute “idiopathic” peripheral facial palsy: Clinical, serological, and cerebrospinal fluid findings and effects of corticosteroids

INTRODUCTION The causes for peripheral facial palsy remain obscure in many patients. Evidence exists suggesting viruses, especially those belonging to the herpesvirus group, may be causative. This study was developed to evaluate this theory. METHODS One hundred forty-seven patients with acute peripheral facial palsy of primarily unknown origin were studied. All were examined within 1 week of onset. Subsequent follow-up was undertaken until the palsy had recovered or become static. Paried cerebral spinal fluid and serum samples were obtained for serological evaluation to detect herpes simplex, varicella zoster, cytomegalovirus, measles, mumps, rubella, tick-borne encephalitis, adenovirus, Epstein-Barr virus, and human immunodeficiency virus, as well as the antibodies to Borrelia burgdorferi. RESULTS Elevated antibiotic titers to Borrelia burgdorferi were observed in 11% of patients, whereas 9% of patients demonstrated elevated viral titers. Antibody pattern consistent with Epstein-Barr virus reactivation was present in 13%. A total of 67% were classified as idiopathic. CONCLUSION Patients with reactivated Epstein-Barr virus were characterized by having a higher incidence of auricular pain and displayed diabetes mellitus in a higher frequency than in other groups. In the Borrelia group, neck/back pain was more common. Healing was less favorable in the Borrelia group despite an equal rate of palsy at onset and adequate antibiotic treatment. Corticosteroid treatment used in 44% of the patients did not significantly improve the functional outcome.

Gain and Phase Characteristics of Compensatory Eye Movements in Light and Darkness:A Study with a Broad Frequency-band Rotatory Test

Thirteen normal subjects were investigated with a broad frequency-band (up to 4.5 Hz) rotatory test. The vestibular stimulation consisted of either a pseudo-random or a sinusoidal frequency sweep oscillation. Eye movements were recorded by EOG. Head movements were recorded either by a potentiometer attached to the chairs axis of rotation or by an angular rate sensor attached to a biteboard . Gain and phase values between eye and head movements were calculated. Measurements were performed in light and darkness during the execution of various fixation tasks. In the higher frequency range there was a in gain and phase between potentiometer and rate sensor measurements due to movement of the head relative to the headholder . Visual suppression, in agreement with earlier studies, was more effective during a sinusoidal stimulation than during a pseudo-random stimulation at low frequencies, using the more precise rate sensor measurement technique. Different instructions in the dark could alter the gain values at lower frequencies (up to 2 Hz) during sinusoidal stimulation. During pseudo-random stimulation no such differences could be elicited. Under all test conditions with the rate sensor, the gain values approached unity at about 3 Hz.

Impairment of Visuo-Vestibular Interaction in Humans Exposed to Toluene

15 healthy volunteers were investigated in a vestibulo-oculomotor test battery during toluene exposure. The concentration was comparable to the threshold limit value. The results were compared to an identical air experiment. The intoxication caused an impaired visual suppression during a pseudo-random oscillatory swing test and also an increased saccade speed. Other vestibular-oculomotor parameters were normal. The findings are in accordance with our earlier study on styrene in humans, showing that the visual suppression test and the saccade test are sensitive parameters assessing neurotoxic influences by organic solvents.

Vestibulo-oculomotor disturbances caused by industrial solvents.

Animal experiments show that intoxication with hydrocarbon solvents influences the vestibulo-oculomotor reflex arc and indicate that the solvents block the inhibition of the vestibulo-oculomotor reflex presumably exerted by the cerebellum. The blood concentrations necessary to elicit oculomotor disturbances in animals were smaller than those that disturbed the vestibular function. Accordingly, in human experiments styrene and toluene exposure did not elicit any positional nystagmus but caused an increased saccade speed and a diminished visual suppression of vestibular nystagmus. Some cerebellar clinical pathologic process in patients who suffer from a psycho-organic syndrome caused by solvents leads us to believe that the cerebellum might be the most vulnerable part of the brain. Some patients had a positional nystagmus, but the most prominent pathologic signs were elicited by the visual suppression test. Our findings compare well with the increased saccade speed and diminished visual suppression in patients with cerebellar tumors and infarctions.

Quantification of slow compensatory eye movements in patients with bilateral vestibular loss : A Study with a Broad Frequency-band Rotatory Test

Seven patients with bilateral vestibular dysfunction were investigated with a new broad frequency oscillatory test. The vestibular stimulation was of two types: a pseudo-random oscillation in the frequency range 0.5-4 Hz and a sinusoidal frequency sweep from 0.5 to 3.5 Hz. Compensatory eye movements were recorded by EOG. Gain and phase values between eye and head movements were extracted using power spectral analysis technique. Two different visual conditions were used: 1) fixating a stationary target and /) fixating a moving target (visual suppression test). At high frequencies all patients showed a reduced VOR gain compared to normal subjects. At low frequencies gain values were close to normal when using a predictable (sinusoidal) stimulation. With a non-predictable (pseudo-random) stimulation gain values were significantly reduced even at low frequencies. The patients with the most severe loss showed a phase lag at higher frequencies (condition 1). The results in the oscillatory test were compared to subjective symptoms and caloric responses. The new test appears to be better suited to assess the vestibular function in patients with suspected bilateral vestibular loss than the caloric test or other traditional procedures.

Xylene Exposure Electronystagmographic and Gaschromatographic Studies in Rabbits

Complaints of vertigo from people who are exposed to industrial solvents have focused interest on their toxic effect on the nervous system. In order to evaluate the influence of an organic solvent, xylene, on the mammalian vestibular system, a series of rabbit experiments were performed. To achieve a constant concentration, the xylene was infused as a lipid emulsion. Blood concentrations were estimated by gas chromatography. Elec-tronystagmography in darkness revealed that at blood xylene concentrations of 30 ppm all rabbits had a positional nystagmus. The beat direction was the opposite of positional alcohol nystagmus. Another difference between the alcohol and the xylene reaction was that rotatory nystagmus responses were exaggerated. The relations between the present findings and the reactions and blood concentrations in people exposed to industrial solvents are discussed.

Bell's palsy ‐ part of a polyneuropathy?

Some authors have suggested that Bells palsy should be considered a part of a polyneuritis cranialis and others, reporting Bells palsy in patients with diabetes mellitus, proposed that it is an overt sign of a sub‐clinical polyneuropathy. To study whether nerves other than the facial nerve were affected, the clinical findings of 112 patients with Bells palsy were correlated with a quantitative EMG done on an asymptomatic leg muscle. The electromyographic results obtained from these leg muscles showed changes similar to those occurring in peripheral nerve lesions, and the changes correlated well with the degree of facial palsy. The results indicate that the patients with symptomatic facial dysfunction have an acute subclinical polyneuropathy.