The nature of spontaneous cavernosal activity

OBJECTIVE

To determine the characteristics of spontaneous cavernosal activity (SCA) and to relate this to previous descriptions of spontaneous potentials from the cavernosum (single potential analysis of cavernosal activity, SPACE).

SUBJECTS AND METHODS

The SCA was recorded in 31 normal men with no sexual problems; various manipulations were applied using concentric-needle (CN), bipolar needle (BN) and surface electrodes. The electrical activity was compared with the observed slow retractile movements of the flaccid penis and with other assessments of electrical activity from skin.

RESULTS

SCA appeared synchronously from both sides of the cavernosal bodies in all normal subjects when detected by CN electrodes. The synchronous recordings both by CN and BN electrodes, or both by CN and surface electrodes registered similar oscillatory potentials. Slow retractile movements of the penis occurred synchronously with these potentials in all subjects and both were absent during erection.

CONCLUSION

SCA is apparently related to biomechanical slow movement artefacts of the flaccid penis: it may be a consequence of the summed contractions of smooth muscle groups in the cavernosum. Observing the small retractile slow movements of the flaccid penis and recording the SCA may be a useful indirect method to characterize cavernosal neural innervation and smooth muscle activity.

Autonomic nerve involvement and venous leakage in diabetic men with impotence

OBJECTIVE

To determine the neurophysiological and vascular factors in diabetic impotence, particularly the role of autonomic neuropathy on venous leakage and erectile impotence.

PATIENTS AND METHODS

Thirty-four diabetic men with impotence were investigated using various neurophysiological and radiological methods. The results were compared with those from patients with idiopathic penile venous leakage for autonomic neuropathy, especially for spontaneous cavernosal activity (SCA).

RESULTS

Of the neurophysiological tests, the SCA was most frequently abnormal, with the loss of normal periodic oscillations. Penile venous leakage, either alone or with arterial insufficiency, was the most frequent vascular problem (67%) in patients with diabetic impotence, in whom the SCA was absent in most (83%). Conversely, the SCA was normal in all impotent patients with idiopathic venous leakage.

CONCLUSION

Venous leakage in diabetic patients is probably produced by autonomic dysfunction of the penile vascular innervation or degeneration of penile smooth muscles, because the SCA was absent more often in these patients.

Motor-evoked potentials from various levels of paravertebral muscles in normal subjects and in patients with focal lesions of the spinal cord

STUDY DESIGN

This prospective study includes normal control subjects and patients with focal lesions of the spinal cord investigated by transcranial magnetic stimulation.

OBJECTIVES

To establish a stable method to elicit motor evoked potentials from cervical to lumbar segmental levels and to apply the method that would allow the localization in patients with restricted cord lesion. Thirty-four healthy subjects (10 women, 24 men) and 17 patients with focal spinal lesions were admitted to this study.

SUMMARY OF BACKGROUND DATA

The focal cord lesions and injuries were previously evaluated by the records of lower limb muscles after cortical stimulation, but this method did not demonstrate the vertebral levels at which the lesions were located.

METHODS

The paravertebral myotomal-evoked potentials were recorded in different segmental levels (T1, T6, T12, and L3) from paravertebral muscles, using surface and needle electrodes by transcranial magnetic stimulation in normal control subjects and patients.

RESULTS

In normal control subjects, paravertebral myotomal-evoked potentials were obtained from T1, T6, T12, and L3 paravertebral muscles with both recording techniques (surface and needle electrode). From T1 to L3 latencies of paravertebral myotomal-evoked potentials increased gradually (from 10 msec to 17 msec) in normal control subjects. The levels of spinal cord lesions were obtained reliably in 14 of 17 patients with thoracic-lumbar spinal cord lesions, by using both electrophysiologic methods. In 11 of 14 patients, the lesions produced total conduction block, at and below the lesion level. In the remaining 3 patients slowing of intersegmental conduction was observed along the focal cord lesion.

CONCLUSIONS

The paravertebral myotomal-evoked potentials obtained by surface electrode from paravertebral muscles and by midline needle electrode in the intrinsic rotatory muscles of the spine were useful in localizing lesions in the spinal segments in most of the patients with thoracic-lumbar cord lesions.

Continuous muscle fibre activity: a case treated with acetazolamide

A case is reported of the continuous muscle fibre activity syndrome, which includes a group of disorders characterised by sustained motor unit activity due to hyperactivity of peripheral nerve motor axons. In this patient the muscle stiffness and myokymic movements were successfully treated with acetazolamide, which acts as a membrane stabiliser either by blockade of chloride and bicarbonate membrane transport or by producing kaliuresis and raising the transmembrane potential by decreasing extracellular potassium.

Local heat effect on sympathetic skin responses after pain of electrical stimulus

OBJECTIVE

To investigate the analgesic effort of local superficial heating by studying sympathetic skin responses.

DESIGN

Randomized trial.

SETTING

Electromyography laboratory in the department of physical therapy and rehabilitation of a university hospital.

SUBJECTS

Twenty healthy volunteers participated with informed consent.

INTERVENTIONS

Sympathetic skin response (SSR) amplitudes following electrical stimulation of the right peroneal nerve and skin temperatures in both hands were recorded simultaneously. All of the recordings were repeated at 5-minute intervals during local heat application over the right palm and within 15 minutes after heat application was stopped.

RESULTS

SSR amplitudes in both hands decreased significantly during local heating (p < .05) and did not return to their initial levels within 15 minutes of the recovery period; the reductions remained statistically significant (p < .05). Amplitude reductions were statistically more significant on the heated hand compared with those on the contralateral hand (p < .05).

CONCLUSION

Therapeutic local heat application reduces the sudomotor response to a painful stimulus. This analgesic effect may be due to suppression of cortical pain sensation resulting from increased levels of endorphins, and may also be a result of local inhibition of both afferent and efferent C fibres.

Electrodermal activity in patients with Parkinson's disease

Peripheral sympathetic activity was investigated in 25 Parkinson's disease (PD) patients and 27 healthy subjects by measuring the skin resistance level (SRL) and skin resistance response (SRR) at the palm of the hand during rest, auditory stimulation and patellar tendon tapping. Blood flow to the hand was also monitored. Normal responses were obtained from all the 27 healthy subjects with both stimuli. All but one of the 25 PD patients responded to sound, six patients failed to respond to patellar tendon tapping and one patient failed to respond to both stimuli. The SRRs (when detectable) of PD patients were always smaller in amplitude than those of normal subjects. It was also observed that while an electrodermal response was present, no vasomotor response could be elicited by either stimulus in some patients. The opposite was true in some other patients. When response latencies were evaluated, it was found that although the mean latency of SRRs evoked by tendon taping was shorter than the mean latency of responses to auditory stimuli in normal subjects, this was not the case in PD patients. SRR mean latency to patellar tendon tapping was significantly longer in PD patients compared with that in normal subjects. Mean latencies of responses to auditory stimuli were the same for both normal subjects and patients. The ratio of the SRR amplitude to SRL (i.e. relative change in SRL) during both types of stimulation was significantly smaller in PD patients than in normal subjects. All the above findings were also true when blood flow to the tissue was interrupted briefly. These findings support the conjecture that the abnormal peripheral sympathetic neural responses associated with PD may arise from a functional disorder in the basal ganglia that influence the efferent autonomic pathway, from impairment of the intermediolateral column of the spinal cord, and possibly from cognitive deficits.