Simone Messerotti Benvenuti

Association between depression and heart rate variability in patients after cardiac surgery: A pilot study☆

OBJECTIVE Depression is a risk factor for cardiovascular diseases. Reduced heart rate variability (HRV), which reflects altered autonomic nervous system activity, has been suggested as one of the mechanisms linking depression to cardiovascular diseases. However, the relationship between depression and HRV has not yet been investigated in patients undergone cardiac surgery. Therefore, the main aim of this study was to examine whether postoperative depression could be related to reduced HRV. METHODS Eleven patients with depression and 22 patients without depression, who had undergone cardiac surgery, were enrolled postoperatively. In all patients, HRV was derived from a four-minute blood volume pulse recording at rest. Analyses of covariance and partial correlations, while controlling for anxiety, were used to examine the associations between postoperative depression and each HRV parameter. RESULTS Compared to non-depressed patients, patients with depression showed significantly lower standard deviation of N-to-N intervals (SDNN) (p=.02), root mean square successive difference of N-to-N intervals (rMSSD) (p=.001), and high-frequency power (p=.002). Partial correlation analyses showed that depression was inversely related to SDNN (r=-.49, p=.005), rMSSD (r=-.58, p=.001), and high-frequency power (r=-.41, p=.02), whereas it was unrelated to other HRV parameters (ps>.09). CONCLUSIONS The current findings extend the depression-reduced HRV relationship to the patients after cardiac surgery. Also, our study suggests that postoperative depression is more likely to be associated with reduced vagal modulation on the heart than with excessive sympathetic activity.

Multimodal Brain Monitoring Reduces Major Neurologic Complications in Cardiac Surgery

OBJECTIVE Although adverse neurologic outcomes are common complications of cardiac surgery, intraoperative brain monitoring has not received adequate attention. The aim of the present study was to evaluate the effectiveness of multimodal brain monitoring in the prevention of major brain injury and reducing the duration of mechanical ventilation, intensive care unit, and postoperative hospital stays after cardiac surgery. DESIGN A retrospective, observational, controlled study. SETTING A single-center regional hospital. PARTICIPANTS One thousand seven hundred twenty-one patients who had undergone cardiac surgery with cardiopulmonary bypass from July 2007 to July 2010. One hundred sixty-six patients with multimodal brain monitoring and a control group without brain monitoring (N = 1,555) were compared retrospectively. INTERVENTIONS Multimodal brain monitoring was performed for 166 patients, consisting of intraoperative recordings of somatosensory-evoked potentials, electroencephalography, and transcranial Doppler. MEASUREMENTS AND MAIN RESULTS The incidence of major neurologic complications and the duration of mechanical ventilation, intensive care unit, and postoperative hospital stays were considered. Patients with brain monitoring had a significantly lower incidence of perioperative major neurologic complications (0%) than those without monitoring (4.06%, p = 0.01) and required significantly shorter periods of mechanical ventilation (p = 0.001) and intensive care unit stays (p = 0.01) than controls. The length of postoperative hospital stays did not differ significantly between the 2 groups (p = 0.57). CONCLUSIONS This preliminary study suggests that multimodal brain monitoring can reduce the incidence of neurologic complications as well as hospital costs associated with post-cardiac surgery patient care. Furthermore, intraoperative brain monitoring provides useful information about brain functioning, blood flow velocity, and metabolism, which may guide the anesthesiologist during surgery.

Influence of impulsiveness on emotional modulation of response inhibition: An ERP study

OBJECTIVE To examine how impulsiveness influences the emotional modulation of behavioral and neural correlates of response inhibition. METHODS Twenty-nine healthy individuals scoring high (HI, N=16) or low (LI, N=13) on motor impulsiveness performed an emotional Go/Nogo task, including the presentation of pleasant, neutral and unpleasant pictures. Behavioral [reaction times (RTs), accuracy to Go and Nogo trials] and neural (Nogo-N2 and Nogo-P3) correlates of response inhibition were compared between HI and LI groups. RESULTS Larger Nogo-P3 was found for emotional than neutral stimuli in HI relative to LI group. Faster RTs to Go stimuli and lower accuracy to Nogo stimuli were correlated with larger Nogo-P3 in HI, but not LI, group. No significant interactions between emotion content and impulsiveness for Nogo-N2 and behavioral measures were noted. CONCLUSIONS Impulsiveness influences the emotional modulation of response inhibition by potentiating the response tendencies evoked by the emotional stimuli. Accordingly, high impulsive individuals may need an increased and/or more effortful response inhibition in order to counteract the prepotent tendency to respond elicited by the combination of high trait impulsiveness and high emotional arousal. SIGNIFICANCE The present study suggests the importance to examine how pathological impulsiveness may interact with emotional arousal in modulating response inhibition.

Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients

This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.

Preexisting depressive symptoms are associated with long-term cognitive decline in patients after cardiac surgery.

OBJECTIVE To examine whether preoperative psychological dysfunctions rather than intraoperative factors may differentially predict short- and long-term postoperative cognitive decline (POCD) in patients after cardiac surgery. METHOD Forty-two patients completed a psychological evaluation, including the Trail Making Test Part A and B (TMT-A/B), the memory with 10/30-s interference, the phonemic verbal fluency and the Center for Epidemiological Studies of Depression (CES-D) scale for cognitive functions and depressive symptoms, respectively, before surgery, at discharge and at 18-month follow-up. RESULTS Ten (24%) and 11 (26%) patients showed POCD at discharge and at 18-month follow-up, respectively. The duration of cardiopulmonary bypass significantly predicted short-term POCD [odds ratio (OR)=1.04, P<.05], whereas preoperative psychological factors were unrelated to cognitive decline at discharge. Conversely, long-term cognitive decline after cardiac surgery was significantly predicted by preoperative scores in the CES-D (OR=1.26, P<.03) but not by intraoperative variables (all Ps >.23). CONCLUSIONS Our findings showed that preexisting depressive symptoms rather than perioperative risk factors are associated with cognitive decline 18 months after cardiac surgery. This study suggests that a preoperative psychological evaluation of depressive symptoms is essential to anticipate which patients are likely to show long-term cognitive decline after cardiac surgery.

Neurofeedback Training for Tourette Syndrome: An Uncontrolled Single Case Study

Gilles de la Tourette syndrome (TS) is characterized by motor and vocal tic manifestations, often accompanied by behavioral, cognitive and affective dysfunctions. Electroencephalography of patients with TS has revealed reduced Sensorimotor Rhythm (SMR) and excessive fronto-central Theta activity, that presumably underlie motor and cognitive disturbances in TS. Some evidence exists that neurofeedback (NFB) training aimed at enhancing SMR amplitude is effective for reducing tics. The present report is an uncontrolled single case study where a NFB training protocol, involving combined SMR uptraining/Theta downtraining was delivered to a 17-year-old male with TS. After sixteen SMR-Theta sessions, six additional sessions were administered with SMR uptraining alone. SMR increase was better obtained when SMR uptraining was administered alone, whereas Theta decrease was observed after both trainings. The patient showed a reduction of tics and affective symptoms, and improvement of cognitive performance after both trainings. Overall, these findings suggest that Theta decrease might account for some clinical effects seen in conjunction with SMR uptraining. Future studies should clarify the feasibility of NFB protocols for patients with TS beyond SMR uptraining alone.

Depression and reduced heart rate variability after cardiac surgery: The mediating role of emotion regulation

BACKGROUND Heart rate variability (HRV), as an index of autonomic nervous system (ANS) functioning, is reduced by depression after cardiac surgery, but the underlying mechanisms of this relationship are poorly understood. Poor emotion regulation as a core symptom of depression has also been associated with altered ANS functioning. The present study aimed to examine whether emotion dysregulation could be a mediator of the depression-reduced HRV relationship observed after cardiac surgery. METHODS Self-reported emotion regulation and four-minute HRV were measured in 25 depressed and 43 nondepressed patients after cardiac surgery. Mediation analysis was conducted to evaluate emotion regulation as a mediator of the depression-reduced HRV relationship. RESULTS Compared to nondepressed patients, those with depression showed lower standard deviation of normal-to-normal (NN) intervals (p<.05), root mean square successive difference of NN intervals (p<.004), and number of interval differences of successive NN intervals greater than 50ms (NN50) (p<.05). Increased low frequency (LF) in normalized units (n.u.) and reduced high frequency (HF) n.u. were also found in depressed compared to nondepressed patients (ps<.01). Mediation analysis revealed that suppression of emotion-expressive behavior partially mediated the effect of depression on LF n.u. and HF n.u. CONCLUSIONS Results confirmed previous findings showing that depression is associated with reduced HRV, especially a reduced vagal tone and a sympathovagal imbalance, after cardiac surgery. This study also provides preliminary evidence that increased trait levels of suppression of emotion-expressive behavior may mediate the depression-related sympathovagal imbalance after cardiac surgery.

Posture affects emotional responses: A Head Down Bed Rest and ERP study

Body posture, mainly represented by horizontal bed rest, has been found to be associated with cortical inhibition, altered perceptual and cognitive processing. In the present research, the influence of Head Down Bed Rest (HDBR)--a condition also termed simulated microgravity--on emotional responses has been studied. Twenty-two male subjects were randomly assigned to either Sitting Control or HDBR group. After 3-h, subjects attended to a passive viewing emotional task in which 75 IAPS slides, divided into 25 pleasant, 25 neutral and 25 unpleasant, were presented in random order for 6s each, while EEG was recorded from F7, F8 and Pz locations. Results showed in Sitting Controls the expected greater P300 and Late Positive Potential (LPP) to pleasant and unpleasant compared with neutral slides, an effect which indicates greater processing of emotional arousing stimuli. The HDBR group showed smaller non-significant differences among all emotional conditions in both ERP components. Arousal and valence subjective evaluations, typically less sensitive to experimental manipulation, did not differentiate groups. The observed ability of HDBR to inhibit cortical emotional responses raises an important issue on the risk that astronauts underestimate a dangerous/threatening situation or that long-term bedridden inpatients develop depressive symptoms.

Change in behavioral functional capacity is associated with preexisting cognitive function rather than with cognitive decline in patients 1 year after cardiac surgery

OBJECTIVE The objective was to examine whether preexisting cognitive function rather than cognitive decline associated with intraoperative procedures may predict change in behavioral functional capacity in patients 1 year after cardiac surgery. METHOD Forty-five patients completed a cognitive evaluation, including the Trail Making Test part B (TMT-B) for attention and psychomotor speed, the Memory with 10-s interference for working memory, the Digit Span test for short-term memory and the Instrumental Activities of Daily Living (IADLs) questionnaire for behavioral functional capacity, before surgery and 1 year after cardiac surgery. RESULTS Sixteen patients (36%) exhibited cognitive decline after cardiac surgery. Preoperative scores on TMT-B significantly predicted change in behavioral functional capacity as measured by IADLs (beta = 0.371, P < .05), whereas the postoperative cognitive decline and intraoperative variables were unrelated to residualized change scores in IADLs (all Ps > .08). CONCLUSIONS Preexisting cognitive dysfunctions as assessed by TMT-B can be a marker of preoperative brain dysfunction, which, in turn, in addition to brain damage caused by cardiac surgery procedures, may further predispose patients to poor behavioral functional capacity and outcome 1 year after surgery. Impaired cognitive functions before surgery should be considered when evaluating the effects of cardiac surgery procedures on long-term behavioral functional status of patients.

Biomedical and psychological risk in cardiac surgery: is EuroSCORE a more comprehensive risk measure than Stroke Index?

OBJECTIVE Several composite risk score indices, the most common being the Stroke Index and the European System for Cardiac Operative Risk Evaluation (EuroSCORE), have been developed to predict perioperative events such as cerebrovascular accidents or death. The main aim of the present study was to compare the preoperative associations between the Stroke Index or the EuroSCORE with anxiety, depression, memory, attention, and executive functions scores in patients undergoing cardiac surgery. METHODS Ninety-one patients were required to perform a preoperative psychological evaluation. Trail Making Test A and B (TMT A/B), Memory with 10 and 30s interference, Digit Span Test, Phonemic Fluency, State and Trait Anxiety Inventory (STAI Y1/Y2), and Center for Epidemiological Study of Depression Scale (CES-D) were administered. The Stroke Index and the EuroSCORE were also considered for each patient. Correlations between the Stroke Index or the EuroSCORE, mood, and neuropsychological scores were performed. RESULTS Seventy-seven patients completed the psychological evaluation. The Stroke Index was significantly correlated with TMT A (ρ=0.40, p=0.001), TMT B (ρ=0.38, p=0.001), Memory with 10s (ρ=-0.34, p=0.003) and 30s (ρ=-0.40, p=0.001) interference, and Phonemic Fluency (ρ=-0.29, p=0.01), but not with Digit Span Test (ρ=-0.18, p=0.13), STAI Y1 (ρ=0.08, p=0.44), STAI Y2 (ρ=0.06, p=0.56), and CES-D (ρ=0.11, p=0.31) scores. The EuroSCORE was significantly correlated not only with TMT A (ρ=0.49, p=0.001), TMT B (ρ=0.42, p=0.001), Memory with 10s (ρ=-0.23, p=0.04) and 30s (ρ=-0.35, p=0.002) interference, Phonemic Fluency (ρ=-0.28, p=0.01), and Digit Span Test (ρ=-0.28, p=0.01) but also with STAI Y1 (ρ=0.27, p=0.02), STAI Y2 (ρ=0.23, p=0.04), and CES-D (ρ=0.26, p=0.02). CONCLUSIONS While both the Stroke Index and the EuroSCORE account for the relationship between biomedical and cognitive risk factors in predicting perioperative risk, only the EuroSCORE also accounts for affective dysfunctions, which, in turn, have been proved to represent risk factors for perioperative adverse events. Therefore, compared with the Stroke Index, the EuroSCORE can be considered a more complete risk index in predicting perioperative risk. Data also suggest that a comprehensive preoperative evaluation of biomedical, mood, and cognitive performances might provide a more accurate mirror of the actual risk in patients undergoing cardiac surgery.