John P. Kline

Differential resting quantitative electroencephalographic alpha patterns in women with environmental chemical intolerance, depressives, and normals

BACKGROUND Previous research suggests that a subset of individuals with intolerance to low levels of environmental chemicals have increased levels of premorbid and/or comorbid psychiatric disorders such as depression, anxiety, and somatization. The purpose of this study was to evaluate the psychological profiles and quantitative electroencephalographic (qEEG) profiles at baseline of women with and without chemical intolerance (CI). METHODS Participants were middle-aged women who reported illness from the odor of common chemicals (CI, n = 14), depressives without such intolerances (D, n = 10), and normal controls (N, n = 11). They completed a set of psychological scales and underwent two separate qEEG recording laboratory sessions spaced 1 week apart, at the same time of day for each subject. RESULTS CI were similar to D with increased lifetime histories of physician-diagnosed depression (71% vs. 100%), Symptom Checklist 90 (revised) (SCL-90-R) somatization scores, Barsky Somatic Symptom Amplification, and perceived life stressfulness, although D had more distress than either CI or N on several other SCL-90-R subscales. CI scored significantly higher on the McLean Limbic Symptom Checklist somatic symptom subscale than did either D or N. On qEEG, CI exhibited significantly greater overall resting absolute alpha activity with eyes closed, especially at the parietal midline site (Pz), and increased (sensitized) frontal alpha from session 1 to 2, in contrast with the D and N groups. D showed right frontal asymmetry in both sessions, in comparison with CI. CONCLUSIONS The data indicate that CI with affective distress diverge from both D without chemical intolerance and N in qEEG alpha patterns at resting baseline. Although CI descriptively resemble D with increased psychological distress, the CIs greater alpha suggests the possibility of a) central nervous system hypo-, not hyper-, activation; and/or b) an overlap with EEG alpha patterns of persons with positive family histories of alcoholism.

Event-Related Potential Amplitude/Intensity Slopes Predict Response to Antidepressants

We measured event-related potential (ERP) component amplitudes to four intensities of randomly presented tones. Patients diagnosed with major depressive disorder were tested prior to and following a clinical trial of antidepressant medication. Slope of P2 amplitude as a function of stimulus intensity was calculated for each subject and condition. Subjects were divided into two groups (responders and nonresponders) based on their Hamilton Rating Scale for depression scores following treatment. Responders had significantly larger P2 slopes prior to treatment than did nonresponders. P2 slopes did not differ significantly between responders and nonresponders following antidepressant treatment. These data support the conclusion that P2 amplitude/intensity slope may be a predictor of response to treatment with antidepressant medication.

Heart rate, heart rate variability, and heartbeat detection with the method of constant stimuli: slow and steady wins the race

The literature on heartbeat detection is fraught with disagreement about appropriate methods. Some laboratories advocate the heartbeat counting method, whereas others advocate the method of constant (MCS) stimuli task. Advocates of the MCS task argue that the heartbeat counting task is confounded by expectancies of heart rate, whereas the MCS task has the virtue of assessing individual heartbeat sensations. In this paper, we present preliminary evidence that heart rate information may also influence performance on the MCS task. Heartbeat detection was predicted by decreased heart rate variability and decreased heart rate. The results suggest that the temporal patterning of heartbeats may influence performance on the MCS task.

Perceptual and electroencephalographic registration of masked emotional words in defensiveness: An exploratory study☆

Abstract This study measured perceptual and electroencephalographic responses to masked pleasant, unpleasant, neutral and sexual words in participants scoring as high defensive (N = 22) or low defensive (N = 30) on the EPQ-L. Six words of each category were presented in random order in ascending durations between 50.1 ms random letter masks. A word identification task designed to elicit impression management (i.e. by requiring participants to say sexual words aloud), preceded a word detection task designed to assess perceptual sensitivity (i.e. by having subjects quietly choose from among words from the same category). Sexual words appeared to elicit impression management, which did not differ between groups. Patterns of detection accuracies for the various emotional word categories differed for high and low defensive participants in a manner consistent with individual differences in unconscious processing of emotional words. Parallel differences emerged in patterns of electroencephalographic α (8–13 Hz) decreases in response to the words, with unconscious effects having a posterior topography.

Quantitative EEG patterns during nose versus mouth inhalation of filtered room air in young adults with and without self-reported chemical odor intolerances

Individuals who report illness (e.g. nausea, headache) from common chemical odors tend to report CNS symptoms suggestive of olfactory-limbic system involvement. This study compared the resting quantitative electroencephalographic (qEEG) patterns of young adult college students reporting subjectively elevated chemical odor intolerance ratings (HICI) with those of controls reporting little or no odor intolerance (LOCI). Each group was subdivided into those with higher (HIDEP) vs. lower (LODEP) ratings of concomitant depression. Nineteen channels of EEG were recorded during a single session over four separate rest periods, respectively, following baseline, cognitive, chemical exposure and olfactory identification tests. Each recording involved two 30-s, eyes-closed, filtered room air breathing conditions: (1) nose inhalation followed by mouth exhalation and (2) mouth inhalation followed by mouth exhalation. HICI showed significantly less beta 1 (beta 1) over the temporal-central region during nose than during mouth inhalation. Over some temporal and central leads, task, DEP and CI interacted to influence beta 1 as well. For theta (theta), CI differences emerged during nose inhalation after the cognitive task at Cz, after chemical exposures at C3, Cz and C4 and after the olfactory ID task at C4. CI differences emerged during mouth breathing after the olfactory ID task at Cz, C4 and T4. The T5-T6 coronal array showed significant CI differences after chemical exposures during nose breathing and during mouth breathing after the cognitive and olfactory ID tasks. The theta findings in the HICI may be related to reports of disturbed attention in CI.

Repressive/Defensive Coping and Identification Thresholds for Pleasant and Unpleasant Words

This study examined the relationship between repressive/defensive coping and identification thresholds for pleasant and unpleasant words. Word identification thresholds were determined by presenting masked words at increasing durations until correct report. Identification thresholds were greater for unpleasant than for pleasant words. When the difference between identification thresholds for unpleasant and pleasant words was standardized, high-defensive participants showed this effect to a greater degree than low-defensive participants. One possible interpretation of the findings is that avoidance of unpleasant stimuli takes place, and that repressive/defensive participants are more prone to it. Alternatively, the findings may reflect a general perceptual bias for pleasant stimuli that is greater for high defensive participants. Such a perceptual bias for pleasant stimuli may facilitate avoidance of unpleasant ones.

Another Opening in the Explanatory Gap

Taylor’s paper purports to bridge the explanatory gap between neurophysiological function and phenomenal experience (PE). He suggests properties of PE, attempts to show how these properties map onto underlying neural information processing, and argues that a particular form of neural network, the locally recurrent network, has the requisite properties for producing the most elemental forms of PE, or qualia. Part of the task of his paper is to explicate a theory of consciousness in a manner that is accessible to neuroscience, philosophy, and psychology. To Taylor’s credit, he succeeds in making the basic idea behind neural networks comprehensible. Yet, even with the technical sophistication and thought that obviously went into his paper, aspects of the model are unclear. The paper is very complex, as any theory of the explanatory gap should be. The gap has been around for a long time and will not disappear easily. Unfortunately, Taylor’s theory tends to be somewhat elusive as the paper progresses. It begins with a discussion of qualia (e.g., elemental experiential properties such as ‘‘redness’’), and then goes on to build on subjective aspects of PE. This implies that the theory will build sets of qualia into PE, but never is explicit about what the specific qualia are. Instead, a list of allegedly fundamental properties of PE, which appear to be quite separable from qualia are listed with some seemingly arbitrary criteria for neural underpinnings. This sort of conceptual slippage in the presence of the intricate and technical details of the neural networks made the paper frustratingly difficult to follow. Locally recurrent networks might provide an excellent model of the formation and combination of elemental representations, but it is not clear how this would necessarily result in PE itself. Taylor’s implicit argument appears to be thus:

Cognitive behavioral treatment of posttraumatic stress disorder subsequent to a motor vehicle accident: A case example

A high-functioning 27-year-old male with no prior psychiatric history developed posttraumatic stress disorder and marital problems subsequent to a motor vehicle accident. His treatment with exposure-based behavior therapy was augmented by involving his wife in exposure homework assignments. The additional inclusion of marital sessions that focused on increasing intimacy levels appeared to facilitate recovery. Upon completion of treatment, the patient returned to baseline levels of functioning. At 16-week follow-up, the patient remained asymptomatic. Treatment implications for the interconnection between PTSD symptoms and relationship difficulties are discussed.