Respiratory sinus arrhythmia and auditory processing in autism: modifiable deficits of an integrated social engagement system?

The current study evaluated processes underlying two common symptoms (i.e., state regulation problems and deficits in auditory processing) associated with a diagnosis of autism spectrum disorders. Although these symptoms have been treated in the literature as unrelated, when informed by the Polyvagal Theory, these symptoms may be viewed as the predictable consequences of depressed neural regulation of an integrated social engagement system, in which there is down regulation of neural influences to the heart (i.e., via the vagus) and to the middle ear muscles (i.e., via the facial and trigeminal cranial nerves). Respiratory sinus arrhythmia (RSA) and heart period were monitored to evaluate state regulation during a baseline and two auditory processing tasks (i.e., the SCAN tests for Filtered Words and Competing Words), which were used to evaluate auditory processing performance. Children with a diagnosis of autism spectrum disorders (ASD) were contrasted with aged matched typically developing children. The current study identified three features that distinguished the ASD group from a group of typically developing children: 1) baseline RSA, 2) direction of RSA reactivity, and 3) auditory processing performance. In the ASD group, the pattern of change in RSA during the attention demanding SCAN tests moderated the relation between performance on the Competing Words test and IQ. In addition, in a subset of ASD participants, auditory processing performance improved and RSA increased following an intervention designed to improve auditory processing.

Autonomic regulation in fragile X syndrome.

Autonomic reactivity was studied in individuals with fragile X syndrome (FXS), a genetic disorder partially characterized by abnormal social behavior. Relative to age-matched controls, the FXS group had faster baseline heart rate and lower amplitude respiratory sinus arrhythmia (RSA). In contrast to the typically developing controls, there was a decrease in RSA with age within the FXS group. Moreover, within the FXS group heart rate did not slow with age. The FXS group also responded with an atypical increase in RSA to the social challenge, while the control group reduced RSA. In a subset of the FXS group, the autonomic profile did not change following 2 months and 1 year of lithium treatment. The observed indices of atypical autonomic regulation, consistent with the Polyvagal Theory, may contribute to the deficits in social behavior and social communication observed in FXS.

Autonomic predictors of recovery following surgery: a comparative study.

Although heart rate and temperature are continuously monitored in patients during recovery following surgery, measures that extract direct manifestations of neural regulation of autonomic circuits from the beat-to-beat heart rate may be more sensitive to outcome. We explore the relationship between features of autonomic regulation and survival in the prairie vole, a small mammal, with features of vagal regulation of the heart similar to humans. Cardiac vagal regulation is manifested in the beat-to-beat heart rate variability (HRV) pattern and can be quantified by extracting measures of the amplitude of periodic oscillations associated with spontaneous breathing. Thus, monitoring beat-to-beat heart rate patterns post-surgery in the prairie vole may provide an opportunity to dynamically assess autonomic adjustments during recovery. Surgeries to implant telemetry devices to monitor body temperature and continuous ECG in prairie voles are routinely performed in our laboratory. Ten of these implanted prairie voles died within 48 h post-surgery. To compare the post-surgery autonomic trajectories with typical surviving prairie voles, the post-surgery data from 17 surviving prairie voles were randomly selected. The data are reported hourly for 27 prairie voles between 6 and 14 h (1h before the demise of the first subject) post-surgery. Receiver operator curves were calculated hourly for each variable to evaluate sensitivity in discriminating survival. The data illustrate that measures of HRV are the most sensitive indicators. These findings provide a foundation for investigating further neural mechanisms of cardiovascular function.

Emotion recognition in children with autism spectrum disorders: relations to eye gaze and autonomic state.

Respiratory Sinus Arrhythmia (RSA), heart rate, and accuracy and latency of emotion recognition were evaluated in children with autism spectrum disorders (ASD) and typically developing children while viewing videos of faces slowly transitioning from a neutral expression to one of six basic emotions (e.g., anger, disgust, fear, happiness, sadness, and surprise). Children with ASD were slower in emotion recognition and selectively made more errors in detecting anger. ASD children had lower amplitude RSA and faster heart rate. Within the ASD group, children with higher amplitude RSA recognized emotions faster. Less severe ASD symptoms and increased gaze to the eye region in children with ASD were related to more accurate emotion recognition.

Electroencephalogram and heart rate regulation to familiar and unfamiliar people in children with autism spectrum disorders.

Few studies have examined whether familiarity of partner affects social responses in children with autism. This study investigated heart rate regulation (respiratory sinus arrhythmia [RSA]: The myelinated vagus nerve's regulation of heart rate) and temporal-parietal electroencephalogram (EEG) activity while nineteen 8- to 12-year-old children with autism and 14 controls viewed videos of a familiar and an unfamiliar person reading a story. Children with autism had lower overall RSA levels and exhibited decreased RSA to the unfamiliar person, versus control children. Both groups decreased temporal-parietal EEG activity to the unfamiliar person. Higher RSA was related to higher social skill ratings and fewer problem behaviors. Thus, the social difficulties of children with autism may be characterized by specific mobilization to unfamiliar people.

The relationship of systemic TNF-alpha and IFN-gamma with IVF treatment outcome and peripheral blood NK cells.

BACKGROUND: To evaluate the association of serum tumour necrotic factor (TNF)-alpha and interferon (IFN)-gamma levels with IVF treatment outcome and peripheral blood NK cells. METHODS: Prospective observational study of 126 randomly selected women who underwent IVF treatment. The serum levels of TNF-alpha and IFN-gamma were determined by multiplex suspension beads array system. RESULTS: There were no significant differences with regard to the systemic TNF-alpha and IFN-gamma levels between the pregnant (n = 51, TNF-alpha: 53.5 pg/mL; IFN-gamma: 4.6 pg/mL) and not pregnant (n = 75, TNF-alpha: 63.0; IFN-gamma: 7.5) women after IVF treatment. For those women with a positive pregnancy after IVF treatment, the systemic TNF-alpha and IFN-gamma levels were higher in those women who miscarried (n = 13, TNF-alpha: 67.4; IFN-gamma: 9.1) when compared with those who had a live birth (n = 38, TNF-alpha: 48.7; IFN-gamma: 1.4), however this difference was not statistically significant. Interestingly, the systemic TNF-alpha and IFN-gamma levels were significantly higher in women who had a higher level of activated (CD69(+)) NK cells (n = 39, TNF-alpha: 86.8; IFN-gamma: 4.7) when compared with women who had a low level of activated NK cells (n = 87, TNF-alpha: 46.9; IFN-gamma: 1.7 P = 0.028 and 0.045 respectively). CONCLUSION: The systemic levels of TNF-alpha and IFN-gamma have no association with implantation rate or miscarriage rate in women undergoing IVF treatment. However, high levels of TNF-alpha and IFN-gamma are associated with elevated levels of activated NK cells and this may subsequently exert a negative impact on reproduction.

The effect of serum concentration of leukaemia inhibitory factor on in vitro fertilization treatment outcome.

PROBLEM: To evaluate the association of peripheral leukaemia inhibitory factor (LIF) levels on implantation and miscarriage rates after in vitro fertilization (IVF) treatment. METHODS: Prospective observational study of 120 randomly selected women who underwent IVF treatment. The concentration of LIF in serum was determined by enzyme-linked immunosorbent assay. RESULTS: There was no significant differences with regard to the systemic mean LIF concentration between the pregnant (42 patients, LIF: 11.55 pg/mL +/- 5.3 S.D.) and non-pregnant (66 patients, LIF: 13.47 pg/mL +/- 5.1 S.D.) women after IVF treatment. Likewise, for those women who have positive pregnancy after IVF treatment, the systemic mean LIF levels were not significantly different between women who have an ongoing pregnancy (34 ongoing pregnancy, LIF: 11.26 pg/mL +/- 5.2 S.D.) and those who had miscarriage (eight miscarriage, LIF: 12.78 pg/mL +/- 5.6 S.D.). CONCLUSION: The systemic levels of LIF concentration have no association with implantation rate or miscarriage rate in women undergoing IVF treatment. Measuring serum LIF concentration prior to embryo transfer in IVF treatment has no predictive value of implantation rate or miscarriage rate.