[Course of the descending central sympathetic pathway. Results of sweat secretion tests following stereotaxic subthalamotomy]

The location and characteristics of the thermal sudomotor pathways in the human brainstem: A reappraisal

To elucidate location and characteristics of the central thermoregulatory sudomotor pathway in the human brainstem, thermoregulatory sweating (TS) in 91 patients with focal brainstem lesions was studied. TS was symmetric or minimally asymmetric in 40 subjects (Group S), and was apparently asymmetric in 51 patients (Group AS). In Group AS, the main abnormality was ipsilateral segmental hypohidrosis with a varying extent, involving predominantly the upper half of the body. Lesion locations, correlations between thermoregulatory sweat test results, and other autonomic and somatic functions were compared between the groups. The results suggested following: (1) The hypothalamospinal pathway related to TS may pass through the posterior hypothalamus and descend in the dorsolateral part of the brainstem, near the spinal trigeminal and spinothalamic tracts; (2) the pathway may descend together with those related to oculosympathetic and vasoconstrictor systems, but each of these may form distinct fiber groups; (3) the majority of the central TS fibers may reach ipsilateral sudomotor sympathetic neurons of the spinal cord, even though some fibers may cross at various levels; (4) in this descending pathway, somatotopic arrangements corresponding to each of the spinal sympathetic segments must be present; (5) There may be another fiber group passing through the central to dorsal paramedian portions of the brainstem, and lesions of these fibers also result in asymmetric TS, but seldom in oculosympathetic dysfunction. This second pathway probably exerts contralateral inhibitory influence on TS, but its origin, intracerebral course and exact physiological function require further clinical investigations.

Combined testing of autonomic and sensory dysfunction in patients with unilateral facial flushing and sweating during exercise

AIMS OF THE STUDY

Patients with unilateral facial flushing are occasionally referred to clinical neurophysiological evaluation with the question of the site of lesion. These patients may have a mixture of autonomic and sensory symptoms. We wanted to study to which extent a combined autonomic and sensory clinical neurophysiological testing before and after exercise may help in the diagnostic evaluation of the patients.

PATIENTS AND METHODS

Five patients were investigated at rest with quantitative sensory thresholds (QST, measurement of thermal thresholds) and quantitative sudomotor axon reflex test (QSART) in all extremities. Sweet volumes (QSWEAT) and skin temperatures were then measured after 30 to 60 minutes of exercise.

RESULTS

Marked side-to-side differences were observed for QST and QSART at rest as well as for QSWEAT and skin temperatures following exercise, in accordance with the patients' symptoms. However, asymptomatic abnormal findings were also demonstrated in the feet of four patients, following both crossed and non-crossed distributions. EMG/neurography and MRI-findings were normal in all patients and no aetiological explanations were found.

CONCLUSION

Combined autonomic and sensory testing including the legs provided evidence of unexpectedly more widespread abnormalities, including asymptomatic findings. Although the patients presented with seemingly similar symptoms, there was a striking heterogeneity in their results, suggesting different sites of dysfunction. An extracranial lesion was considered likely in one or maybe two patients, while the possibility of a central lesion had to be considered in the three other patients.

THE POSTERIOR SUBTHALAMIC AREA IN THE TREATMENT OF MOVEMENT DISORDERS

THE INTRODUCTION OF thalamotomy in 1954 led naturally to exploration of the underlying subthalamic area, with the development of such procedures as campotomy and subthalamotomy in the posterior subthalamic area. The most popular of these procedures was the subthalamotomy, which was performed in thousands of patients for various movement disorders. Today, in the deep brain stimulation (DBS) era, subthalamic nucleus DBS is the treatment of choice for Parkinson's disease, whereas thalamic and pallidal DBS are mainly used for nonparkinsonian tremor and dystonia, respectively. The interest in DBS in the posterior subthalamic area has been quite limited, however, with a total of 95 patients presented in 14 articles. During recent years, interest has increased, and promising results have been published concerning both Parkinson's disease and nonparkinsonian tremor. We reviewed the literature to investigate the development of surgery in the posterior subthalamic area from the lesional era to the present.

Postoperative management of subthalamic nucleus stimulation for Parkinson's disease

The postoperative neurologic management of patients with deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson' s disease is a complex dynamic process that involves a progressive increase in stimulation intensity and a parallel decrease in antiparkinsonian medication while assessing the interactions of both treatments. Neurologists responsible for postoperative management of patients receiving STN DBS must have expert knowledge of the electroanatomy of the subthalamic area and be familiar with the medical treatment of motor and nonmotor symptoms, including the management of long-term complications of levodopa treatment. Neurosurgeons who perform DBS need to understand the principles that guide the postoperative adaptation of treatment. This article defines guidelines for setting stimulation parameters, adapting drugs and managing adverse effects.

Bilateral suppression of the sympathetic nervous system in hemispheric brain infarction

To assess sympathetic system function after hemispheric brain infarction rostral to the hypothalamus we investigated 24 patients with infarction in the territory of the middle cerebral artery. Anisocoria and basal lacrimal gland secretion were determined. The ninhydrin test was performed and the sympathetic skin response recorded in both hands and feet. The functions assessed by these tests were found to be reduced bilaterally. No significant lateralisation of the sympathetic nervous system could be demonstrated.

Autonomic and thermal sensory symptoms and dysfunction after stroke

BACKGROUND AND PURPOSE

Symptoms interpreted as unilateral disturbances of autonomic function, such as coldness, dryness, sweating, and trophic changes, are well known but incompletely understood clinical problems after stroke. The present study provides data related to the incidence and mechanisms behind such symptoms.

METHODS

Temperature perception thresholds, skin temperatures, evaporation rates, and skin blood flow responses were measured bilaterally in 37 stroke patients aged 58 +/- 13 years (mean +/- SD) and in a control group of 15 patients aged 64 +/- 15 years with a single transient ischemic attack.

RESULTS

Of the 37 stroke patients, 43% reported a sensation of coldness in the contralesional side of the body. Basal skin blood flow and temperature were relatively lower in the contralesional side. There was an excess of evaporation in the contralesional side after brain stem lesions and in the ipsilesional side after hemispheric lesions. Vasomotor reflex asymmetries occurred in 34% of the patients and were due to weak vasodilator or vasoconstrictor reflexes in the ipsilesional side. These abnormalities correlated significantly to sensations of unilateral coldness, hypalgesia, and thermohypesthesia in the contralesional side and anatomically to lesions in spinothalamo-cortical pathways.

CONCLUSIONS

Focal central nervous system lesions due to stroke may result in symptoms and measurable evidence of unilateral disturbance of skin sympathetic function. Vasomotor asymmetries are probably due to lesions of vasomotor pathways descending uncrossed. Subjective coldness may be due to disturbed central processing.

The telodiencephalic ischemic syndrome

A new cerebral syndrome is described which occurs rather frequently with ischemia affecting the common pathway of the internal carotid and middle cerebral arteries. The syndrome consists of contralateral brachiofacial hemiparesis, possibly with hemianopia and/or aphasia, and ipsilateral thermoregulatory hemihypohidrosis with an ipsilateral central Horner syndrome. It is caused by an ischemic lesion of the crossed pathways descending from the cerebrum and the uncrossed hypothalamo-spinal sympathetic pathways descending through the subthalamic region. It is suggested to name the syndrome "telodiencephalic ischemic syndrome".