Biomedical subjects

S W Porges

Publications and source records attributed to S W Porges.

74 records · Page 5Linked to original sources

PubMedDate not supplied

Vagal reactivity and affective adjustment in infants during interaction challenges.

Respiratory sinus arrhythmia (RSA) and heart period were evaluated in 5-month-old infants (N = 40) during interaction challenges requiring affective adjustment. The paradigm consisted of four 2-min experimental conditions designed to elicit behavioral and autonomic responses to object-mediated (Picture Attention and Toy Attention) and person-mediated (Still Face and Social Interaction) engagement. The data demonstrated that autonomic state systematically changed during engagement and disengagement with the environment. During the object-mediated challenge, increases in RSA were uniquely related to positive engagement. During the person-mediated challenge, there was a more complex integration of autonomic and behavioral responses characterized by concordant increases and decreases in RSA, heart period, positive engagement, negative affect, and motor activity. When participants were partitioned into two groups, based on their RSA response pattern during the person-mediated challenge, only participants who exhibited a pattern of RSA decrease from Toy Attention to Still Face followed by a rapid recovery during Social Interaction demonstrated regulation of behavioral activity, including concordant recovery from stress. These findings provide additional empirical support for the role of vagal regulation of the heart in the modulation of affective adjustment and engagement behavior.

Affect↗

PubMedDate not supplied

Use of power spectral analysis of respiratory sinus arrhythmia to detect graft rejection.

Some evidence has suggested that graft rejection in heart transplant recipients is accompanied by sinus node dysfunction. To test this hypothesis the electrocardiograms of 21 orthotopic heart transplant recipients receiving cyclosporine were recorded at regularly scheduled biopsies. This resulted in 105 good quality recordings of at least 10 minutes each. All exhibited normal sinus rhythm. These recordings were then processed through patented digital routines that calculated the power spectrum of the RR intervals. All recordings exhibited Mayer wave and respiratory sinus arrhythmia (RSA) periodicities. Peak spectral power of RSA (PSP-RSA) demonstrated good repeatability at 2 weeks (r = 0.81). A paired t test comparing the baseline PSP-RSA in eight subjects who experienced rejection episodes with their individual average PSP-RSA during periods of rejection revealed a significant decrease (p = 0.039). As a global measure, PSP-RSA greater than 1 (natural logarithmic scales) demonstrated a sensitivity of 1.0, specificity of 0.42, positive predictive value of 0.22, and negative predictive value of 1.0. These tentative results demonstrate that PSP-RSA may be a sensitive, noninvasive marker for graft rejection of heart transplant patients receiving cyclosporine for immunosuppression. A larger, more extensive study needs to be conducted to confirm these results.

Adult↗