Autonomic Neuropathies: The Earliest Abnormalities. In: Struppler A, Weindl A, editors. Electromyography and Evoked Potentials. Berlin: Springer Berlin Heidelberg; 1985. pp. 251-5. [DOI: 10.1007/978-3-642-70122-1_41]

Sympathetic skin response (SSR) is abnormal in multiple sclerosis

As the function of the autonomic nervous system is often compromised in multiple sclerosis (MS), different standardized tests are used to detect disseminated abnormalities in cardiovascular autonomic functions. sympathetic skin response (SSR), a slow wave generated in deep layers of the skin, is induced by reflex activation of sudomotor sympathetic efferent fibers. SSR was studied in 70 patients classified into different categories according to the diagnostic criteria for MS. We also obtained pattern reversal visually evoked potentials and brainstem auditory evoked potentials as well as somatosensory evoked potentials (by median and posterior tibial nerve stimulation). SSR was abnormal in 66 patients (94.2%), including abnormal foot latency with normal hand latency in 30 (42.8%), delayed foot and hand latencies in 30 (42.8%), and no response in 6 (8.6%). The percentages of SSR abnormalities were similar in the different patient categories. Pathological SSR were more common than abnormal evoked potentials in suspected and probable MS. SSR appears to be a simple and effective means of assessing sympathetic sudomotor outflow disturbances in MS, providing a valuable addition to current electrophysiological procedures for the detection of MS lesions.

Automatic analysis of heart rate variation: II. Findings in patients attending an EMG laboratory

An automatic method was used to measure the heart rate variation with breathing in patients with different neuromuscular conditions attending a laboratory of electromyography (EMG). The objective was to determine the frequency of abnormalities in various conditions and the relationship between R-R variation and different nerve conduction parameters. The percentages of reduced R-R variation were 73% in diabetics, 35% in Guillain-Barré syndrome, 22% in amyotrophic lateral sclerosis, and 50% in amyloidosis. R-R variation in diabetics was significantly correlated to most parameters of nerve conduction. In Guillain-Barré syndrome it correlated significantly with the ulnar and median M-response amplitudes. Most patients with myopathies showed normal R-R variation.

Automatic analysis of heart rate variation: I. Method and reference values in healthy controls

Many patients referred to an electrophysiological laboratory may have autonomic dysfunction. Some parasympathetic tests are based on the assessment of heart rate variation induced by breathing, Valsalva maneuver, and standing. We have developed fast and practical computer-based methods to analyze heart rate variation using standard EMG equipment and a personal computer. For quantitative description we have evaluated different algorithms, both earlier described and new ones. Findings in patients with diabetes have been compared with those obtained from healthy subjects in order to determine the diagnostic utility of the various algorithms. The optimal algorithm has been chosen by this and other criteria, and a reference database from healthy subjects has been developed.