Magnetic coil stimulation of the brachial plexus.

This study establishes a protocol and normal values for magnetic stimulation of the brachial plexus at the mid-clavicular point. We evaluated twenty normal subjects bilaterally, and determined normal latencies to the abductor pollicis brevis, abductor digiti minimi, biceps, triceps, deltoid, infraspinatus, latissimus dorsi, and rhomboid major. Our values were comparable to latency values obtained with electrical stimulation at Erb's point and reported in the literature. Patient's compared their comfort between electrical stimulation and magnetic stimulation and magnetic stimulation was found more comfortable. To demonstrate that magnetic stimulation is an easier and less painful method to study brachial plexus injuries, we report two cases where we were unable to record evoked responses with electrical stimulation at Erb's point yet easily obtained magnetic recordings.

Somatosensory and magnetic evoked potentials in a postoperative paraparetic patient: case report.

Somatosensory evoked potential (SSEP) testing is increasingly being used to test for spinal cord injuries and to monitor spinal surgery to reduce the risk of paraplegia. It is a sensory test, but it is assumed that any process severe enough to affect the motor tracts will also affect the sensory tracts and, therefore, be identified. Increasingly, however, isolated motor-tract involvement has been reported. A new technique, magnetic coil stimulation of the cortex, directly monitors the motor tracts. We report a case where the SSEP was normal although the magnetic motor-evoked potential was abnormal, supporting the hypothesis that direct testing of motor tracts may be advantageous.

Anterior interosseous/median nerve latency ratio.

This report describes a new diagnostic technique for evaluating anterior interosseous nerve injuries (Kiloh Nevin syndrome). The resultant "AIM" (anterior interosseous/median nerve) score establishes a normal ratio of the pronator quadratus latency to the abductor pollicis brevis latency after one stimulus to the proximal median nerve and simultaneous recordings of the evoked response at the respective muscles. One hundred normal nerves were tested in 61 patients. The result was an AIM score of 0.60 (SD = 0.06). Five patients with Kiloh Nevin syndrome were evaluated. The average AIM score was 0.76 (SD = 0.04). Five patients with severe carpal tunnel syndrome were evaluated. The average AIM score was 0.38 (SD = 0.06). Ten patients with borderline carpal tunnel syndrome were evaluated. The average AIM score was 0.48 (SD = 0.06). Anterior interosseous nerve entrapment or compression injury remains a difficult clinical diagnosis because it is mainly a motor nerve and the syndrome is often mistaken for finger ligamentous injury. We describe an easily performed electrodiagnostic latency ratio technique to diagnose this injury. This technique may also be helpful as a screen for carpal tunnel syndrome when it is difficult to control for systemic illness.

Multicentre double-blind comparison of sustained action formulations of tiaprofenic acid and indomethacin in osteoarthritis.

In a randomised double-blind, multicentre, crossover study, the short term efficacy and tolerance of a sustained action preparation of tiaprofenic acid 600 mg once daily was compared with sustained release indomethacin 75 mg once daily in 98 patients with osteoarthritis. After a minimum washout period of 3 days, patients were randomly allocated to receive each treatment in turn for a period of 4 weeks. There were no significant differences between the 2 treatments in the clinical assessments of pain level, duration of morning stiffness, articular index and functional impairment performed at the end of each treatment period. High pain levels on movement were reduced by both treatments, and reduction was also seen in night pain, where initial levels were lower. There was no significant difference between the number of patients who reported side effects on the 2 treatments. 37 patients (39%) reported 49 side effects while taking sustained release tiaprofenic acid, and 35 patients (37%) reported 53 side effects while taking sustained release indomethacin. Daily diary cards showed that both treatments provided improvements in duration of morning stiffness and in pain relief. Thus sustained action tiaprofenic acid and sustained release indomethacin were shown to be equally well tolerated and efficacious.

Antinuclear antibodies in ankylosing spondylitis, psoriatic arthritis, and psoriasis.

Granulocyte-specific antinuclear antibodies (GS-ANA) were detected in the sera of 5 of 88 patients with ankylosing spondylitis (AS) and in 7 of 52 cases of psoriatic arthritis (PsA), but were not found in 91 patients with malignant or non-malignant chest disease nor in 25 cases of psoriasis. Organ non-specific ANA were present in serum from 6 cases of AS and 1 of PsA. None of the sera gave significant levels for soluble immune complexes as detected by a C1q-binding assay. The presence of antinuclear antibodies was not associated with clinical features or drug therapy in either AS or PsA.

Antibody-dependent and PHA-induced cellular cytotoxicity in rheumatoid arthritis.

One hundred and thirty nine observations of antibody-dependent cell mediated cytotoxicity (ADCC) were made on 77 with rheumatoid arthritis (RA) and 17 healthy controls. There were no differences in ADCC between these 2 groups or within the RA group with regard to disease activity, duration, seropositivity, or drug treatment. Sixty observations of phytohaemagglutinin induced cytotoxicity were made on 22 patients with RA and 10 healthy controls. Again there were no differences in cytotoxicity between the 2 groups.

Middle ear function in rheumatoid arthritis.

Using an otoadmittance meter the function of the middle ear was compared in 38 patients with rheumatoid arthritis (RA) and 30 matched controls with non-articular rheumatism. Patients with pre-existing ear disease were excluded from the study. No subjects in either group showed hearing loss on pure tone audiometry, but otoadmittance abnormalities were recorded in 16 of the RA (42%) and in 2 of the control groups (7%). The pattern of abnormality was similar in each case and indicated an increased laxity of the conducting system. The reason for this unexpected finding is unknown. There were no significant differences between the RA patients with normal or abnormal recordings as regards clinical or laboratory features or treatment.

Otoadmittance measurements in patients with rheumatoid arthritis.

Analysis of middle ear function has for many years been accomplished by acoustic impedance measurements and this has proved of great clinical value. The vectors which contribute to impedance are functions of mass, stiffness and resistance of the system and information about these components may be obtained by use of the otoadmittance meter. The shape of the tympanogram may be altered both by pathologies which change the relative magnitude of the vectors and by variation in the probe tone frequency. Patients with rheumatoid arthritis (55 ears) were compared with a series of controls (50 ears); 38% of 'rheumatoid ears' demonstrated a marked notch on the 660 Hz susceptance curve whilst only 8% of the control group showed this abnormality. The pattern suggests a decrease in the stiffness of the transducer mechanism in rheumatoid arthritis.

Eosinophil-specific and other granulocyte-specific antinuclear antibodies in juvenile chronic polyarthritis and adult rheumatoid arthritis.

Sera from 151 children of whom 112 had juvenile chronic polyarthritis (JCP), and from adults with rheumatoid arthritis (RA), and from healthy pregnant females were tested for the presence of granulocyte-specific antinuclear antibodies (GS-ANA). These were detected in 20% of sera from cases of JCP, in 68% of adult RA, but in none of the controls. Eosinophil-specific ANA were the only ANA present in 18% of positive children and 54% of the positive adults. GS-ANA in children were predominantly IgG and of low titre. Heat-stable GS-ANA were detected in sera from eight children but none bound complement. The presence of GS-ANA was not significantly associated with sex, age of onset, duration of disease, mean active joint count, mean ESR, nor with the presence of fever, rash, splenomegaly, amyloidosis, pericarditis, or rheumatoid factor.