Assessment of Autonomic Function in Stroke Patients by Power Spectral Analysis of Heart Rate Variability

OBJECTIVE: To evaluate the effects of orthostatic stress with a head-up tilt on the autonomic nervous system and to determine how a cerebral stroke influences the cardiac autonomic function, using the power spectral analysis(PSA) of heart rate variability(HRV). METHOD: We studied 11 stroke patients with a left hemiplegia and 14 patients with a right hemiplegia. Their hemispheric brain lesions were confirmed by the MRI. The ECG and respiration signals were recorded at the tilt angle of 0o and 70o for 5 minutes under the condition of frequency controlled respirtaion(0.25 Hz). Data were compared with the age- and sex-matched 12 healthy controls. RESULT: In a control group, the normalized high frequency power showed a significant decrease during the head-up tilt(p0.05). Compared with the right hemiplegia and control groups, the left hemiplegia group was associated more with a reduced low and high frequency power and showed no significant changes under the orthostatic stress. CONCLUSION: PSA of HRV can identify the reduced cardiac autonomic activity in stroke patients, with a greater reduction in the left hemiplegia group than in the right hemiplegia group, which may cause a high risk of cardiac arrhythmias and sudden death.

Recent Epidemiologic Trends of Stroke

OBJECTIVE: The purpose of this study is to present the epidemiological data on patients with a stroke admitted to the severance hospital, Yonsei University College of Medicine (YUMC) and to investigate the significant risk factors of stroke. METHODS: We reviewed medical records of 532 patients with a stroke admitted to the hospital of from 1992 to 1996 retrospectively. RESULTS: The incidence was highest in the sixth decade. Ischemic stroke (64.3%) was more common than a hemorrhagic stroke (35.7%) and the thrombotic infarction was the leading type (28.3%) of all kinds of stroke. Middle cerebral arterial territory was the most commonly involved site for the thrombotic and embolic stroke. Of the intracerebral hemorrhages, basal ganglia (48.4%) was the most commonly involved site with was followed by the thalamus (24.2%), lobar (19.3%), and cerebellum (6.5%). In subarachnoid hemorrhages, the aneurysm was most frequently located in the middle cerebral artery (34.4%). The possible contributing factors of stroke were hypertension, hypercholesterolemia, cigarette smoking and diabetes mellitus. The common complications during hospitalization were the frozen shoulders, depression, pneumonia, reflex sympathetic dystrophy (RSD), and hydrocephalus. CONCLUSION: This study showed the changing trends of stroke in its distribution of subtypes. Multicenter prospective study using stroke registry would be required for the determination of national epidemiologic trends.

Changes of Dermatomal Somatosensory Evoked Potentials in the Children with Spastic Cerebral Palsy after Selective Posterior Rhizotomy

OBJECTIVE: To evaluate the changes of dermatomal SEP (DSEP) in children with a spastic cerebral palsy (CP) after the selective posterior rhizotomy (SPR). METHOD: The subjects were 14 spastic CP children, with the age from 3 to 6 years old, who underwent SPR. DSEPs were studied at the L2-3, L4, L5, S1 dermatomes bilaterally, pre and postoperatively. Postoperative DSEPs were interpreted by the changes of latency, amplitude and waveforms. RESULTS: 1) All children were spastic diplegia except one who was a spastic hemiplegia. 2) Preoperative DSEPs were flat or severely distorted in 40 of 112 waveforms (34.5%). 3) Postoperative DSEP latencies were no change in 39.3%, improved in 17.9%, and worsened in 25.6% respectively. Amplitudes were no change in 30.8%, improved in 38.5%, and worsened in 13.7% respectively. Waveforms were no change in 64.1%, improved in 22.2%, and worsened in 8.5% respectively. There was no statistical difference of postoperative changes of the 3 categories according to the root levels. CONCLUSION: The results showed that the preoperative DSEPs were abnormal in 34.5% suggestive the lesions of CP being more widespread than strictly involving the motor system. This study confirmed that the most SEPs unchanged by the SPR. A further study for the relationship of postoperative DSEP changes and clinical findings such as functional impairment would be needed.