Physiological and behavioural indices of hostility: an extension of the capacity model to include exposure to affective stress and right lateralized motor stress.

Right hemisphere functional cerebral systems have reliably been associated with sympathetic nervous system arousal and the perception of negative affective events. The goal of the current research was to provide additional support for the capacity model of hostility by examining changes attributable to functional cerebral systems within the right hemisphere using a dual concurrent task paradigm. To incorporate exposure to negative affective and right-lateralized motor stress using this approach, high and low hostile individuals completed a series of grip-strength tasks before and after hearing a recording of angry infant vocalizations. Results supported the capacity model in that high hostile individuals were unable to maintain regulatory control over right hemisphere activation as indicated through increased motor perseveration in the pre- and post-affective stress conditions, heightened systolic blood pressure (SBP) upon exposure to negative emotional sounds, and increased heart rate (HR) following stress. Conversely, low hostile individuals showed improved regulatory control over these regions as evidenced by reduced motor perseveration in the pre- and post-affective stress conditions, maintenance of SBP and reductions in HR following stress. The current data support the capacity model and extend its scope to include exposure to affective and right-lateralized motor stress.

Hyperbaric Oxygen Post Established Stroke.

BACKGROUND AND PURPOSE: Hyperbaric oxygen therapy (HBOT) has been reported to improve neurological function in the chronic phase of stroke in a single trial having significant limitations, including a lack of a sham control. METHODS: We conducted a single-center, parallel-group, randomized trial to determine the effectiveness of HBOT compared with a sham control in adults who were 6 to 36 months post-ischemic stroke. The treatment group received 40 sessions of HBOT at the Vancouver General Hospital Hyperbaric Unit. The control group received 40 sessions of sham treatment designed to replicate an HBOT experience. Due to recruitment challenges and timeline/feasibility tracking by the research team, the control arm was altered after 20 months to a waitlist in the hope of increasing participation. In the second phase, participants were randomized to receive HBOT immediately or following an eight-week observation period. The primary outcome was the post-treatment Stroke Impact Scale-16 (SIS-16). Secondary outcomes included the National Institute of Health Stroke Scale, Berg Balance Test, Digit Symbol Substitution Test, 5-Metre Walk Test, 6-Minute Walk Test, Grip Strength, Montreal Cognitive Assessment, Box/Block Test, and Center for Epidemiological Studies - Depression and Short Form-36. Based on detecting a clinically important between-group difference of 10 on the SIS-16 score, our target sample size was 68 participants per arm.  Results: From January 5, 2016 to October 9, 2018, 34 participants were enrolled in the trial, 27 during the first phase and seven in the second phase. The study was stopped after 36 months, and prior to meeting the sample size target, due to low recruitment. At the end of treatment, the difference in the SIS-16 between groups was 5.5 (95% CI: 1.3 to 9.7, p = 0.01) in favor of the sham group. CONCLUSIONS: Our results exclude a clinically important benefit of HBOT on the primary outcome of the SIS-16. These findings do not support the use of HBOT in chronic stroke survivors.

Cerebral asymmetry in the control of cardiovascular functioning: evidence from lateral vibrotactile stimulation.

Research has supported hemispheric specialisation in the regulation of cardiovascular functioning, with the left hemisphere being associated with parasympathetic functioning and the right hemisphere with sympathetic functioning. We sought to investigate this relationship further using vibrotactile stimulation applied to the palms. Our prediction was that vibrotactile stimulation applied to the left hand would result in increased heart rate and blood pressure, and that stimulation applied to the right hand would result in decreased heart rate and blood pressure. The results indicated significant differences in heart rate change scores in the predicted direction. No differences were noted for systolic or diastolic blood pressure. Hence the findings provide partial support for the lateralisation of autonomic functions.

Laterality in Parkinson's disease: A neuropsychological review.

Laterality of motor symptom onset in Parkinson's disease is both well-known and under-appreciated. Treatment of disorders that have asymmetric pathological features, such as stroke and epilepsy, demonstrate the importance of incorporating hemispheric lateralization and specialization into therapy and care planning. These practices could theoretically extend to Parkinson's disease, providing increased diagnostic accuracy and improved treatment outcomes. Additionally, while motor symptoms have generally received the majority of attention, non-motor features (e.g., autonomic dysfunction) also decrease quality of life and are influenced by asymmetrical neurodegeneration. Due to the laterality of cognitive and behavioral processes in the two brain hemispheres, analysis of hemibody side of onset can potentially give insight into expected symptom profile of the patient and allow for increased predictive accuracy of disease progression and outcome, thus opening the door to personalized and improved therapy in treating Parkinson's disease patients. This review discusses motor and non-motor symptoms (namely autonomic, sensory, emotional, and cognitive dysfunction) of Parkinson's disease in respect to hemispheric lateralization from a theoretical perspective in hopes of providing a framework for future research and personalized treatment.

Influence of left versus right hemibody onset Parkinson's disease on cardiovascular control.

Whereas the left hemisphere is involved in regulating the parasympathetic nervous system, the right hemisphere regulates the sympathetic. Given the asymmetrical onset of motor symptoms and neuropathology in PD, differences in cardiovascular functions might be expected between PD patients with left hemibody onset (LHO) versus right hemibody onset (RHO). A total of 66 PD patients served as participants, including 31 LHO patients and 35 RHO PD patients. All participants had their resting heart rate (HR) and blood pressure (BP) recorded. Although the LHO group had lower systolic BP, it had higher resting HR than did the RHO group. The reason for this dissociation is not known but might be related to asymmetrical vagus nerve control of the heart (SA node). Future researchers might want to use additional indices of cardiovascular functioning that are more precise measures of parasympathetic and sympathetic functioning, as well as learn the influence of dopaminergic medications.

Extending the functional cerebral systems theory of emotion to the vestibular modality: a systematic and integrative approach.

Throughout history, vestibular and emotional dysregulation have often manifested together in clinical settings, with little consideration that they may have a common basis. Regarding vestibular mechanisms, the role of brainstem and cerebellar structures has been emphasized in the neurological literature, whereas emotion processing in the cerebral hemispheres has been the focus in psychology. A conceptual model is proposed that links research in the 2 disparate fields by means of a functional cerebral systems framework. The claim is that frontal regions exert regulatory control over posterior systems for sensation and autonomic functions in a dense, interconnected network. Impairment at levels within the system is expected to influence vestibular and cognitive processes depending on the extent of frontal regulatory capacity. M. Kinsbourne's (1980) shared cerebral space model specifies the conditions under which dysfunction of the vestibular modality will influence higher cognitive levels. A position on laterality and associative relations within the right hemisphere is proposed to explain links among dizziness, nausea, and negative emotion.

Assessment of nonverbal learning and memory using the Design Learning Test.

The laterality of verbal and nonverbal learning and memory to the left and right temporal lobes, respectively, has received much empirical support. Researchers have often used the Rey Auditory Verbal Learning Test (RAVLT) as a measure of verbal learning and memory in these investigations. However, a precise analog of the RAVLT that uses stimuli difficult to encode verbally has not been reported. Further, although researchers have developed some measures that are essentially visuospatial analogs of the RAVLT, no correlational data have been reported attesting to the relation between the measures. The authors report the development of a nonverbal analog of the RAVLT, referred to as the Design Learning Test (DLT). Also, the authors present correlational data supporting a relation between the DLT and RAVLT, and they hope that the present study will stimulate research investigating whether the DLT is sensitive to right temporal lobe functioning.

The influence of hostility on electroencephalographic activity and memory functioning during an affective memory task.

OBJECTIVE: The purpose of this study was to examine the neural correlates of emotional learning and hostility via the use of EEG and the Auditory Affective Verbal Learning Test (AAVL). METHODS: The Cook-Medley Hostility Scale (CMHO) was used to identify right-handed men (N=16) and women (N=44) as low or high hostile. Participants were administered the positive and negative word lists of the AAVL lists, and were asked to recall the words during a 5-trial paradigm. EEG data were recorded from 19 scalp sites before and following learning trials; separate bandwidths of the EEG spectrum were analyzed. RESULTS: As predicted, completion of the negative AAVL resulted in self-reported negative mood induction. Moreover, primacy and recency effects were demonstrated with the negative and positive versions of the AAVL, respectively. Unexpectedly, high hostiles demonstrated greater right versus left hemisphere high alpha power than low hostile counterparts. Low hostiles evidenced greater alpha power and low beta power than did high hostiles. CONCLUSIONS: These results suggest differing patterns of hemispheric asymmetry and overall brain activity for low and high hostiles during emotional learning. SIGNIFICANCE: The findings are important with regard to understanding the relationship between hostility, emotional learning, and associated neural systems.

Emotional influences on spatial attention.

The relationships between the anterior-posterior and left-right regions of the brain have been characterized as mutually inhibitory. Whereas the left hemisphere attends to right proximal hemispace and is associated with positive emotions, the right hemisphere attends to left distal hemispace and is associated with negative emotions. Because of the excitatory and inhibitory influences between the left and right frontal and posterior regions of the brain, the expression of emotion will result in an ipsilateral attentional bias. Given these functional systems, we hypothesized that positive emotions would be associated with a bias for left distal hemispace and negative emotions would be associated with a bias for right proximal hemispace. We tested these hypotheses by having 138 undergraduate students place emotionally labeled pegs on a large board. Our results indicated that the positively labeled pegs were placed in left distal hemispace and the relative placement of negatively labeled pegs was rightward and proximally. Whereas numerous research investigations have examined how attention is biased for emotional stimuli, ours is the first investigation to provide evidence that emotions can bias attentional allocation.

Hostility and cognitive control: Evidence of increased cardiovascular reactivity as a function of exposure to affective stress using a dichotic listening paradigm.

Indices of cognitive control were examined in men with high and low levels of trait hostility as a function of exposure to affective and cognitive stress. A dual concurrent task paradigm was used whereby participants intentionally directed focus to the left or right ear under dichotic listening conditions before and after exposure to angry infant vocalizations. Analysis of the behavioral data supports the prediction of reduced right frontal regulatory control in men with high levels of hostility as indicated by diminished capacity to suppress report of phonemes presented to the language dominant left hemisphere (right ear) in the Focus Left condition. This diminishment in the capacity to suppress report of phonemes presented to the right ear in the Focus Left condition is suggestive of reduced cognitive control. With respect to the neurophysiological data, heart rate increased for only men with high levels of hostility in the Focus Left condition, and this was especially evident in the post-affective stress condition. This increase in right hemisphere arousal provides additional evidence of reduced cognitive control and support for the capacity model of hostility by implicating poor right frontal regulatory control over right posterior cerebral regions under dual task conditions. The results are discussed in terms of integrating the construct of cognitive control into the capacity model as well as providing implications regarding reductions in the capacity to suppress predominant aggressive responses in domestic settings.

Affective verbal learning in hostility: an increased primacy effect and bias for negative emotional material.

The current experiment examined the effects of hostility and a pain stressor on affective verbal learning. Participants were classified as high or low hostile and randomly assigned to a cold pressor or a non-cold pressor group. The subsequent effects on acquisition of the Auditory Affective Verbal Learning Test [AAVLT; Snyder, K. A., & Harrison, D. W. (1997). The Affective Verbal Learning Test. Archives of Clinical Neuropsychology, 12(5), 477-482] were measured. As expected, high hostiles learned negative emotional words significantly better than they learned positive words. Additionally, high hostiles were impaired in their acquisition of verbal material relative to low hostile participants. A significant primacy effect for negative emotional words and an overall better recall of negative information was also found. These results support the idea that high hostiles differ from low hostiles in a number of modalities and demonstrate the persistence of negative emotional material. Future work should address the implications these results have on high hostiles in daily interactions.

Efficacy, safety and patient satisfaction of propofol for procedural sedation and analgesia in the emergency department: a prospective study.

OBJECTIVE: We evaluated the efficacy, safety and patient satisfaction with the use of propofol for procedural sedation and analgesia in the emergency department (ED). METHODS: All patients receiving propofol for procedural sedation and analgesia in the ED between December 1, 2003, and November 30, 2005, were prospectively assessed. Propofol was administered using a standardized protocol, which included an initial dose of 0.25-0.5 mg/kg followed by 10-20 mg/minute until sedated. Efficacy was evaluated using procedural success rate, recovery time and physician satisfaction. Adverse respiratory effects were defined as apnea for more than 30 seconds or an oxygen saturation of less than 90%. Hypotension was defined as systolic blood pressure < 90 mm Hg or > 20% decrease from baseline. Patient and physician satisfaction were determined using 5-point Likert scales. RESULTS: Our study included 113 patients with a mean age of 50 (standard deviation [SD] 19) years; 62% were male. The most common procedures were orthopedic manipulation (44%), cardioversion (37%), and abscess incision and drainage (13%). The mean total propofol dose required was 1.6 (SD 0.9) mg/kg. Procedural success was achieved in 90% of cases and the mean patient recovery time was 7.6 (SD 3.4) minutes. No patient (0%, 95% confidence interval [CI] 0%-3%) experienced apnea; however, 1 patient (1%, 95% CI 0%-5%) experienced emesis, which resulted in an oxygen saturation < 90%. Nine patients (8%, 95% CI 4%-15%) experienced hypotension and 7 (6%, 95% CI 3%-12%) experienced pain on injection. All patients were very satisfied (92%, 95% CI 85%-96%) or satisfied (8%, 95% CI 4%-15%), and 94% (95% CI 88%-98%) reported no recollection of the procedure. The majority of physicians were very satisfied (85%, 95% CI 77%-91%) or satisfied (6%, 95% CI 3%-12%) with the sedation and the conditions achieved. CONCLUSION: When administered as part of a standardized protocol, propofol appears to be a safe and effective agent for performing procedural sedation and analgesia in the ED, and is associated with high patient and physician satisfaction.

The effect of anger expression style on cardiovascular responses to lateralized cognitive stressors.

To determine the effects of self-reported anger expression style on cerebrally lateralized physiological responses to neuropsychological stressors, changes in systolic blood pressure and heart rate were examined in response to a verbal fluency task and a figural fluency task among individuals reporting either "anger in" or "anger out" expression styles. Significant group by trial interaction effects was found for systolic blood pressure following administration of verbal fluency [F(1,54) = 5.86, p < 0.05] and nonverbal fluency stressors [F(1,54) = 13.68, p < .001]. Similar interactions were seen for systolic heart rate following administration of verbal fluency [F(1,54) = 5.86, p < .005] and nonverbal fluency stressors [F(1,54) = 13.68, p < .001]. The corresponding results are discussed in terms of functional cerebral systems and potential implications for physiological models of anger. Given the association between anger and negative physical health outcomes, there is a clear need to better understand the physiological components of anger. The results of this experiment indicate that a repressive "anger in" expression style is associated with deregulation of the right frontal region. This same region has been shown to be intimately involved in cardiovascular recovery, glucose metabolism, and blood pressure regulation.

Spreading activation in emotional memory networks and the cumulative effects of somatic markers.

The theory of spreading activation proposes that the activation of a semantic memory node may spread along bidirectional associative links to other related nodes. Although this theory was originally proposed to explain semantic memory networks, a similar process may be said to exist with episodic or emotional memory networks. The Somatic Marker hypothesis proposes that remembering an emotional memory activates the somatic sensations associated with the memory. An integration of these two models suggests that as spreading activation in emotional memory networks increases, a greater number of associated somatic markers would become activated. This process would then result in greater changes in physiological functioning. We sought to investigate this possibility by having subjects recall words associated with sad and happy memories, in addition to a neutral condition. The average ages of the memories and the number of word memories recalled were then correlated with measures of heart rate and skin conductance. The results indicated significant positive correlations between the number of happy word memories and heart rate (r = .384, p = .022) and between the average ages of the sad memories and skin conductance (r = .556, p = .001). Unexpectedly, a significant negative relationship was found between the number of happy word memories and skin conductance (r = -.373, p = .025). The results provide partial support for our hypothesis, indicating that increasing spreading activation in emotional memory networks activates an increasing number of somatic markers and this is then reflected in greater physiological activity at the time of recalling the memories.

Spreading activation in nonverbal memory networks.

Theories of spreading activation primarily involve semantic memory networks. However, the existence of separate verbal and visuospatial memory networks suggests that spreading activation may also occur in visuospatial memory networks. The purpose of the present investigation was to explore this possibility. Specifically, this study sought to create and describe the design frequency corpus and to determine whether this measure of visuospatial spreading activation was related to right hemisphere functioning and spreading activation in verbal memory networks. We used word frequencies taken from the Controlled Oral Word Association Test and design frequencies taken from the Ruff Figural Fluency Test as measures of verbal and visuospatial spreading activation, respectively. Average word and design frequencies were then correlated with measures of left and right cerebral functioning. The results indicated that a significant relationship exists between performance on a test of right posterior functioning (Block Design) and design frequency. A significant negative relationship also exists between spreading activation in semantic memory networks and design frequency. Based on our findings, the hypotheses were supported. Further research will need to be conducted to examine whether spreading activation exists in visuospatial memory networks as well as the parameters that might modulate this spreading activation, such as the influence of neurotransmitters.

Use of lidocaine and fentanyl premedication for neuroprotective rapid sequence intubation in the emergency department.

INTRODUCTION: Autoregulation is dysfunctional in the injured brain. Increases in intracranial and arterial pressure may therefore result in extension of the primary injury. Rapid sequence intubation (RSI) is a well-known cause of surges in both arterial pressure and intracranial pressure. Neuroprotective agents, namely lidocaine and fentanyl, have the potential to minimize the pressure surges implicated in secondary brain injury. The purpose of this study was to determine the frequency with which neuroprotective agents were used for neuroprotective RSI in the emergency department. METHODS: We conducted a retrospective chart review of all 139 patients intubated in the emergency department of Vancouver General Hospital between March and October 2003. Patients were eligible if there was an indication for neuroprotective agents defined as presumed intracranial pathology and a mean arterial pressure (MAP) > 85 mm Hg. Contraindications to fentanyl included MAP < 85 mm Hg or allergy to fentanyl. RESULTS: Seventy-seven patients were intubated for primary neurological indications. Indication for intubation included non-traumatic causes (n = 37) (including cerebrovascular accident or intracranial hemorrhage) and closed head injury (n = 40). The mean age (+/- standard deviation) was 52.3+/-20.4 years, and 31.4% were female. Fifty-seven (74.0%) patients had indications for neuroprotective agents, without contraindications. When neuroprotective agents were indicated, lidocaine was used in 84.2% (95% confidence interval [CI] 72.6%-91.5%) of patients while fentanyl was used in 33.3% (95%CI 22.4%-46.3%) of patients. Eleven percent of the intubations were performed with a fentanyl dose of delta 2 mcg/kg, which is the lower limit considered effective. CONCLUSIONS: Despite the potential benefit of using lidocaine and fentanyl in appropriate patients undergoing neuroprotective RSI in the emergency department, our study identified a significant underutilization of optimal premedication. The identification of barriers to use and the implementation of strategies to optimize use are necessary.

Functional cerebral space theory: Towards an integration of theory and mechanisms of left hemineglect, anosognosia, and anosodiaphoria.

BACKGROUND: The current case study presents a 43 year old African American woman admitted to a Tertiary Care Rehabilitation unit at a major medical center for concerns over left-sided anesthesia and weakness. Head scans indicate a right middle cerebral arterial distribution infarct altering blood flow in temporal, parietal, and occipital regions in the right cerebral hemisphere. OBJECTIVE: Physician and therapist reports (i.e., speech and occupational therapists) referred the patient for a neuropsychological evaluation for concerns over the patient's capacity to recognize the severity of her deficits and self-care, with potential rule-outs indicated by the extant literature on right CVA for anosognosia, anosodiaphoria, and left hemibody/hemispace neglect. METHODS: The current case integrates interdisciplinary physician notation, magnetic resonance imaging and magnetic resonance angiogram, observations and reports from speech and occupational therapy, and neuropsychological assessment via standardized tests and neurobehavioral syndrome analysis. RESULTS: Evidence was found for co-occurring syndromes of moderate anosognosia, anosodiaphoria, and left hemibody/hemispatial neglect derived from shared functional cerebral space with overlapping temporal, parietal, and occipital damage. CONCLUSIONS: Clinical implications are discussed, including recommendations for therapy approaches based on functional cerebral space theory that may indicate the use of known techniques (e.g., for left hemibody neglect) that may also have therapeutic implications for treating other, more mercurial co-occurring syndromes of anosognosia and anosodiaphoria.

Frontal lobe regulation of blood glucose levels: support for the limited capacity model in hostile violence-prone men.

Hostile men have reliably displayed an exaggerated sympathetic stress response across multiple experimental settings, with cardiovascular reactivity for blood pressure and heart rate concurrent with lateralized right frontal lobe stress (Trajanoski et al., in Diabetes Care 19(12):1412-1415, 1996; see Heilman et al., in J Neurol Neurosurg Psychiatry 38(1):69-72, 1975). The current experiment examined frontal lobe regulatory control of glucose in high and low hostile men with concurrent left frontal lobe (Control Oral Word Association Test [verbal]) or right frontal lobe (Ruff Figural Fluency Test [nonverbal]) stress. A significant interaction was found for Group × Condition, F (1,22) = 4.16, p ≤ .05 with glucose levels (mg/dl) of high hostile men significantly elevated as a function of the right frontal stressor (M = 101.37, SD = 13.75) when compared to the verbal stressor (M = 95.79, SD = 11.20). Glucose levels in the low hostile group remained stable for both types of stress. High hostile men made significantly more errors on the right frontal but not the left frontal stressor (M = 17.18, SD = 19.88) when compared to the low hostile men (M = 5.81, SD = 4.33). These findings support our existing frontal capacity model of hostility (Iribarren et al., in J Am Med Assoc 17(19):2546-2551, 2000; McCrimmon et al., in Physiol Behav 67(1):35-39, 1999; Brunner et al., in Diabetes Care 21(4):585-590, 1998), extending the role of the right frontal lobe to regulatory control over glucose mobilization.

Brain lateralization of emotional processing: historical roots and a future incorporating "dominance".

This article provides a review of research on the hemispheric specialization in emotional processing during the past 40 years and the theoretical models derived from the conceptual analysis of these results. The publications reviewed here were collected to better appreciate the cortical lateralization of emotional perception (visual and auditory), expression (facial and prosodic), and experience. Four major models of emotional processing are discussed--the Right Hemisphere, Valence, Approach-Withdrawal, and Behavioral Inhibition System-Behavioral Activation System models. Observing the relative merits and limitations of these models, a new direction for exploration is offered. Specifically, to better appreciate the strength and direction (i.e., approach versus withdrawal) of experienced emotions, it is recommended that state "dominance" be evaluated in the context of asymmetrical activation of left-frontal (dominance) versus right-frontal (submission) brain regions.

The Ruff Figural Fluency Test: heightened right frontal lobe delta activity as a function of performance.

Research has indicated that the Ruff Figural Fluency Test [RFFT; Ruff, R. M., Light, R. H., & Evans, R. W. (1987). The Ruff Figural Fluency Test: A normative study with adults. Developmental Neuropsychology, 3, 37-51] is sensitive to right frontal lobe functioning. Indeed, research has differentiated between patients with left or right frontal lobe lesions using performance on the RFFT [Ruff, R. M., Allen, C. C., Farrow, C. E., Niemann, H., & Wylie, T. (1994). Figural fluency: Differential impairment in patients with left versus right frontal lobe lesions. Archives of Clinical Neuropsychology, 9, 41-55]. The present investigation used quantitative electroencephalography to test further whether the RFFT was sensitive to right frontal lobe functioning among a group of individuals with no history of head injury. To meet this objective, the RFFT was administered to a group of 45 right-handed men with no history of significant head injury or cerebral dysfunction. Delta magnitude (muV) at three right frontal electrode sites (FP2, F4, F8) was then used to compare those who performed the best (High Fluency) with those who performed the worst (Low Fluency) on the RFFT. The findings indicated heightened right frontal delta magnitude for the Low Fluency group relative to the High Fluency group at the F2 and F8 right frontal electrode sites. Thus, the present findings provide further support for the contention that the RFFT is sensitive to right frontal lobe functioning, even among those with no history of head injury.