Faculty Bibliography

The diagnostic sensitivity of Vibrameter and tuning fork examination towards uremic and alcoholic neuropathy was tested in 75 patients. In 40 uremic and 35 alcoholic patients, we compared the sensitivity of neurological examination, nerve conduction studies (NCS) and vibration thresholds assessed at the malleoli by means of Vibrameter and scaled tuning fork. Vibrameter results were correlated with NCS. Polyneuropathy was diagnosed in 52 patients, but in 16 patients diagnosis depended upon inclusion of Vibrameter testing in the examination protocol. In uremic patients, Vibrameter (47.5%) showed abnormalities as often as NCS (45%), and more often than clinical (32.5%) or tuning fork examination (2.5%). In alcoholic patients, Vibrameter revealed abnormalities more often (60%) than NCS (34.3%) or tuning fork (14.3%). Correlations between NCS and vibratory thresholds were low (-0.52 < or = Rs < or = -0.35). Vibrameter studies are far more sensitive than tuning fork tests. The technique complements NCS and refines the diagnosis of uremic and alcoholic neuropathies

Pathophysiology and pathoanatomy of uremic neuropathy are not yet well understood. A single hemodialysis positively increases nerve conduction velocities of uremic patients, thus demonstrating a functional A alpha-fiber improvement by detoxification. This study tested whether non-invasive Vibrameter and Thermotest studies show a similarly positive effect for A beta-, A delta- and C-fibers and whether the psychophysical techniques might substitute for nerve conduction studies. 20 uremic patients depending on chronic intermittent hemodialysis were examined shortly before and after a hemodialysis. Using a scaled 128 Hz tuning fork, a Vibrameter and a 'Marstock'-Thermotest, vibratory and warm and cold thresholds were assessed at both internal malleoli according to the method of limits. In addition, thermal thresholds were determined at the volar aspect of the non-shunted wrist. In nine patients the Vibrameter showed elevated thresholds before and after dialysis as did six patients with the tuning fork. Warm or cold thresholds were abnormal in four patients before treatment and in eight patients after dialysis. This was due to some patients reporting elevated thresholds after dialysis although they had had normal thresholds before the treatment. Still, the overall sum of abnormal thermal or vibratory thresholds at the different tested body sites had decreased after treatment. Moreover, mean values of thermal and vibratory thresholds of the 20 patients improved with dialysis (p < 0.05). Tuning fork results were too coarse and failed to show a dialysis effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Reports on the incidence of alcoholic polyneuropathies are variable depending on diagnostic tools. In this study, 50 chronic alcoholics with positive MALT (Munich Alcoholism Test) and greater than seven years history of excessive alcohol abuse were examined neurologically. Tibial and peroneal motor and sural nerve conduction velocities (NCV) were studied. Warm and cold perception was evaluated in the area behind the internal malleolus using a Somedic-Thermotest. Thresholds were determined by the method of limits. The effect of a slow, medium and fast temperature change rate on thermal perception was tested. Thirty-eight patients (76%) showed signs of neuropathy. Thermal perception was more often abnormal (62%) than NCV (42%) and clinical examination (56%). A medium temperature change rate of 2.0-2.5 degrees C/s was the most sensitive index of small fiber neuropathy. Thermal threshold measurement proved to be a reliable, sensitive and easy to perform method that should become standard in the examination of polyneuropathies

The use of different paradigms and initial skin and thermode reference temperatures in quantitative thermal testing does not allow strict comparison of results generated from different laboratories. We tested (a) whether the reproducibility of the method of limits is higher for measurement of isolated warm and cold thresholds (WT, CT) as compared to difference limen (DL) thresholds, i.e. values derived from alternating warm and cold stimulation, and (b) whether WT-, CT- and DL-thresholds depend on the value of baseline skin and thermode temperatures. In 20 healthy volunteers WT-, CT-, and DL-thresholds were determined at the volar wrist using a Somedic-Thermotest. In condition A the baseline thermode temperature was set at 30 degrees C, and in conditions B and C at 35 degrees C; in condition C the tested skin area was also warmed to 35 degrees C prior to the test. The randomized tests were repeated within 1-8 days. WT-, CT-, and DL-values were reproducible, but DL-values were more widely spread than WT and CT. CT variability was lowest in condition A, and WT variability in condition C. We conclude that DL determination should be abandoned, since CT and WT better differentiate normal from abnormal thresholds than the coarse DL-values. We recommend the use of the lower baseline thermode temperature (30 degrees C) and elimination of warming of the tested skin area prior to the test

There is limited experience with continuous (>3 days) isoflurane anesthesia for status epilepticus (SE). We present a case with prolonged SE, probably due to thallium intoxication, in which isoflurane successfully suppressed seizure activity over 7 days without adverse effects. When isoflurane was discontinued, seizures returned despite high doses of barbiturates, and the patient died several months later. Early isoflurane anesthesia is an effective alternative therapy in prolonged convulsive SE resistant to common therapy and intravenous general anesthesia. However, its continuous application for several days requires familiarity with anesthesiologic principles, and scavenging of expiratory air.

Detection of thermal hypoaesthesia, hyperalgesia, and paradoxical sensation significantly contribute to the diagnosis of polyneuropathy (PNP). There is controversy about the clinical usefulness of detected heat hypoalgesia. In 50 chronic alcoholic patients we compared the prevalence and diagnostic value of heat hypoalgesia (HPT) to that of cold (CT) and warm (WT) hypoaesthesia using a 'Marstock' thermotest. Clinical examination revealed PNP in 56%, cold hypoaesthesia was present in 62%, warm hypoaesthesia in 24%, paradoxical thermal sensation in 10%, cold and heat hyperalgesia in 12%, and heat hypoalgesia in 22%. Only 1 patient (2%) presented with heat hypoalgesia but normal warm and cold thresholds; he reported paradoxical thermal sensation and had PNP. One patient suffered first degree burn injury from heat pain examination. Heat hypoalgesia contributed least to the diagnosis of polyneuropathy (HPT versus CT: P < 0.001). In patients with sensory loss, testing heat hypoalgesia bears some risk of burn injury. In contrast to thermal hypoaesthesia and hyperalgesia, it does not significantly enrich the diagnostic workup of alcoholic polyneuropathies

Visual evoked potentials were examined in 24 patients (mean age: 51.1 +/- 10.2 years) with primary brain stem lesion. Topographical recordings were performed within the first 3.1 +/- 2.7 days after onset of disease. The results showed an increase in the signal to noise ration-(SNR) parameter and the amplitude over the occipital region in patients with unfavourable outcome. These findings seem to indicate that the VEP topography probably can be used as an additional prognostic parameter in patients with primary brain stem lesions