On time-frequence analysis of heart rate variability

The aim of this research is to develop a time-frequency method suitable to study HRV in greater detail. The following approach was used: • two known time-frequency representations were applied to HRV to understand its advantages and disadvantages in describing HRV in frequency and in amplitude, over time; • a new method was developed that describes the time-varying fluctuations in the characteristic frequency bands of HRV by means of the instantaneous frequency and the instantaneous amplitude with an optimal time-resolution; • an index was developed to separate the oscillatory from the irregular periods in the instantaneous frequency; • from the instantaneous amplitude and frequency, we derived summarizing parameters which we applied to describe the changes in the instantaneous amplitude and frequency over time for the oscillatory and irregular periods separatel

Emotional startle modulation in male patients with recent-onset schizophrenia

Patients with schizophrenia suffer from both cognitive as well as emotional disturbances, leading to reduced social functioning and quality of life. This study investigated the ongoing emotional states of medicated and antipsychotic-free patients and healthy controls using an emotional startle paradigm. During positive, neutral and negative emotional pictures, aversive acoustic startle stimuli were presented at 4 different probe latencies (300, 800, 1300 and 3800 ms) from picture onset. In both patients and controls, positive pictures, and more specifically erotic pictures, elicited significantly smaller eye blinks compared with startle stimuli presented during neutral and negative pictures. With regard to the subjective ratings, medicated patients rated erotic pictures significantly less pleasant and the adventure, nature, and household pictures as significantly more arousing than healthy control subjects. The present results indicate the need to further investigate emotional responding to specific picture contents, with specific focus on the sexual needs and expectations of schizophrenic patients, so as to eventually improve the quality of life in these patients