ObjectivePhysical or mental imbalance caused by harmful stimuli can induce stress to maintain homeostasis. During chronic stress, the sympathetic nervous system is hyperactivated, causing physical, psychological, and behavioral abnormalities. At present, there is no accepted standard for stress evaluation. This review aimed to survey studies providing a rationale for selecting heart rate variability (HRV) as a psychological stress indicator.
MethodsTerm searches in the Web of Science®, National Library of Medicine (PubMed), and Google Scholar databases yielded 37 publications meeting our criteria. The inclusion criteria were involvement of human participants, HRV as an objective psychological stress measure, and measured HRV reactivity.
ResultsIn most studies, HRV variables changed in response to stress induced by various methods. The most frequently reported factor associated with variation in HRV variables was low parasympathetic activity, which is characterized by a decrease in the high-frequency band and an increase in the low-frequency band. Neuroimaging studies suggested that HRV may be linked to cortical regions (e.g., the ventromedial prefrontal cortex) that are involved in stressful situation appraisal.
ConclusionIn conclusion, the current neurobiological evidence suggests that HRV is impacted by stress and supports its use for the objective assessment of psychological health and stress.
We investigated whether the integrity of the corticospinal tract classified by diffusion tensor tractography (DTT) can predict the motor outcome in 25 patients with pontine infarct. DTTs were obtained in the early stage of stroke (5-30 days) and were classified into two groups (type A: the integrity of corticospinal tract was preserved around the infarct; type B: corticospinal tract was interrupted). DTT type A patients showed better motor function than the type B patients at 6 months after onset. DTT obtained at the early stage of pontine infarct appears to have predictive value for motor outcome in patients with pontine infarct.
The aim of this study was to validate a new paper and pencil test battery to diagnose minimal hepatic encephalopathy (MHE) in Korea. A new paper and pencil test battery was composed of number connection test-A (NCT-A), number connection test-B (NCT-B), digit span test (DST), and symbol digit modality test (SDMT). The norm of the new test was based on 315 healthy individuals between the ages of 20 and 70 years old. Another 63 healthy subjects (n = 31) and cirrhosis patients (n = 32) were included as a validation cohort. All participants completed the new paper and pencil test, a critical flicker frequency (CFF) test and computerized cognitive function test (visual continuous performance test [CPT]). The scores on the NCT-A and NCT-B increased but those of DST and SDMT decreased according to age. Twelve of the cirrhotic patients (37.5%) were diagnosed with MHE based on the new paper and pencil test battery. The total score of the paper and pencil test battery showed good positive correlation with the CFF (r = 0.551, P < 0.001) and computerized cognitive function test. Also, this score was lower in patients with MHE compared to those without MHE (P < 0.001). Scores on the CFF (32.0 vs. 28.7 Hz, P = 0.028) and the computer base cognitive test decreased significantly in patients with MHE compared to those without MHE. Test-retest reliability was comparable. In conclusion, the new paper and pencil test battery including NCT-A, NCT-B, DST, and SDMT showed good correlation with neuropsychological tests. This new paper and pencil test battery could help to discriminate patients with impaired cognitive function in cirrhosis (registered at Clinical Research Information Service [CRIS], https://cris.nih.go.kr/cris, KCT0000955).
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