論文研討：Heart rate variability and brain imaging of schizophrenic patients

Abstract

Introduction: Heart rate variability (HRV) has recently been linked to
schizophrenia in several studies. HRV describes the variation in time between
consecutive heartbeats, and is thought to reflect an interplay between the
sympathetic and the parasympathetic branches of the autonomic nervous system
(ANS). High HRV is associated with a healthy ANS and a healthy heart, while in
recent research HRV is found to be significantly reduced in patients with
schizophrenia.
A number of studies have shown that brain regions in schizophrenia patients are
affected, with both diffuse reductions in white and grey matter density and
reductions in specific regions like the cerebellum. In this study we examined
whether brain regions related to HRV regulation have reduced grey matter
density in schizophrenia patients.

Methods: HRV measurements resulted in four variables (root mean of squared
successive interbeat differences: RMSSD, and three frequency variables) that
could be compared for schizophrenic patients and healthy controls. We further
used a questionnaire to measure severity of positive and negative schizophrenic
symptoms. All these variables were included in analyses of MRI scans of the
schizophrenic patients’ brains. We further measured attention using a sustained
attention test.

Results: We found RMSSD to be reduced in schizophrenic patients compared to
controls. Frequency variables, which are linked to sympathetic/parasympathetic
activity, were all higher for the patient group. Furthermore, correlations between
HRV data and both positive and negative symptoms of schizophrenia were found.
MRI analyses showed possible links between HRV and the cerebellum, brain stem
and occipito parietal junction. No correlation between HRV measurements and
sustained attention was found.

Conclusion: In line with earlier studies we found that both HRV and grey matter
density are reduced in schizophrenic patients. In addition we here show a
correlation between HRV and grey matter density and also between HRV and
symptom severity.