Neural correlates of levels of emotional awareness. Evidence of an interaction between emotion and attention in the anterior cingulate cortex

Recent functional imaging studies have begun to identify the neural correlates of emotion in healthy volunteers. However, studies to date have not differentially addressed the brain areas associated with the perception, experience, or expression of emotion during emotional arousal. To explore the neural correlates of emotional experience, we used positron emission tomography (PET) and 15-water to measure cerebral blood flow (CBF) in 12 healthy women during film- and recall-induced emotion and correlated CBF changes attributable to emotion with subjects' scores on the Levels of Emotional Awareness Scale (LEAS), a measure of individual differences in the capacity to experience emotion in a differentiated and complex way. A conjunction analysis revealed that the correlations between LEAS and CBF during film- and recall-induced emotion overlapped significantly (z = 3.74, p < 0. 001) in Brodmann's area 24 of the anterior cingulate cortex (ACC). This finding suggests that individual differences in the ability to accurately detect emotional signals interoceptively or exteroceptively may at least in part be a function of the degree to which the ACC participates in the experiential processing and response to emotion cues. To the extent that this finding is consistent with the functions of the ACC involving attention and response selection, it suggests that this neural correlate of conscious emotional experience is not exclusive to emotion.

Is left frontal brain activation in defensiveness gender specific?

A. J. Tomarken and R. J. Davidson (1994) reported that defensiveness is characterized by relative left frontal brain activation. Because they examined only women, gender differences in this relation are possible. In the present study, resting alpha asymmetries in right-handed men (n = 25) and women (n = 60) were related to defensiveness, measured by the Eysenck Personality Questionnaire L scale. These results were similar to those of Tomarken and Davidson in that defensiveness correlated positively with relative left frontal activation in women. An unexpected finding was that high-defensive men showed relative right frontal activation, a result virtually opposite that for women. These results imply that the nature of defensiveness as a coping strategy may vary as a function of gender.

Appendiceal ultrasonography performed by nonradiologists: does it help in the diagnostic process?

We performed a retrospective study to compare the sensitivity, specificity, predictive value, and diagnostic accuracy of appendiceal ultrasonography performed by unsupervised technicians during the nighttime hours with studies performed during the day by supervised technicians. Fifty-nine percent of the 163 sonographic examinations were done during the day, and 41% were performed at night. The sensitivity during the day (61%) was significantly higher than at night (26%), as was the positive predictive value (93% day, 71% night). We conclude that ultrasonography is an operator-dependent study. Its sensitivity is so diminished when not performed by an experienced radiologist or technician that a negative examination is not reliable.

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 CI's 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.

Is left frontal brain activation in defensiveness gender specific?

A. J. Tomarken and R. J. Davidson (1994) reported that defensiveness is characterized by relative left frontal brain activation. Because they examined only women, gender differences in this relation are possible. In the present study, resting alpha asymmetries in right-handed men (n = 25) and women (n = 60) were related to defensiveness, measured by the Eysenck Personality Questionnaire L scale. These results were similar to those of Tomarken and Davidson in that defensiveness correlated positively with relative left frontal activation in women. An unexpected finding was that high-defensive men showed relative right frontal activation, a result virtually opposite that for women. These results imply that the nature of defensiveness as a coping strategy may vary as a function of gender.

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.

Neuroanatomical correlates of pleasant and unpleasant emotion

Substantial evidence suggests that a key distinction in the classification of human emotion is that between an appetitive motivational system association with positive or pleasant emotion and an aversive motivational system associated with negative or unpleasant emotion. To explore the neural substrates of these two systems, 12 healthy women viewed sets of pictures previously demonstrated to elicit pleasant, unpleasant and neutral emotion, while positron emission tomographic (PET) measurements of regional cerebral blood flow were obtained. Pleasant and unpleasant emotions were each distinguished from neutral emotion conditions by significantly increased cerebral blood flow in the vicinity of the medial prefrontal cortex (Brodmann's area 9), thalamus, hypothalamus and midbrain (P < 0.005). Unpleasant was distinguished from neutral or pleasant emotion by activation of the bilateral occipito-temporal cortex and cerebellum, and left parahippocampal gyrus, hippocampus and amygdala (P < 0.005). Pleasant was also distinguished from neutral but not unpleasant emotion by activation of the head of the left caudate nucleus (P < 0.005). These findings are consistent with those from other recent PET studies of human emotion and demonstrate that there are both common and unique components of the neural networks mediating pleasant and unpleasant emotion in healthy women.

Neuroanatomical correlates of happiness, sadness, and disgust

OBJECTIVE

Happiness, sadness, and disgust are three emotions that differ in their valence (positive or negative) and associated action tendencies (approach or withdrawal). This study was designed to investigate the neuroanatomical correlates of these discrete emotions.

METHOD

Twelve healthy female subjects were studied. Positron emission tomography and [15O]H2O were used to measure regional brain activity. There were 12 conditions per subject: happiness, sadness, and disgust and three control conditions, each induced by film and recall. Emotion and control tasks were alternated throughout. Condition order was pseudo-randomized and counterbalanced across subjects. Analyses focused on brain activity patterns for each emotion when combining film and recall data.

RESULTS

Happiness, sadness, and disgust were each associated with increases in activity in the thalamus and medial prefrontal cortex (Brodmann's area 9). These three emotions were also associated with activation of anterior and posterior temporal structures, primarily when induced by film. Recalled sadness was associated with increased activation in the anterior insula. Happiness was distinguished from sadness by greater activity in the vicinity of ventral mesial frontal cortex.

CONCLUSIONS

While this study should be considered preliminary, it identifies regions of the brain that participate in happiness, sadness, and disgust, regions that distinguish between positive and negative emotions, and regions that depend on both the elicitor and valence of emotion or their interaction.

Neuroanatomical correlates of externally and internally generated human emotion

OBJECTIVE

Positron emission tomography was used to investigate the neural substrates of normal human emotional and their dependence on the types of emotional stimulus.

METHOD

Twelve healthy female subjects underwent 12 measurements of regional brain activity following the intravenous bolus administration of [15O]H2O as they alternated between emotion-generating and control film and recall tasks. Automated image analysis techniques were used to characterize and compare the increases in regional brain activity associated with the emotional response to complex visual (film) and cognitive (recall) stimuli.

RESULTS

Film- and recall-generated emotion were each associated with significantly increased activity in the vicinity of the medial prefrontal cortex and thalamus, suggesting that these regions participate in aspects of emotion that do not depend on the nature of the emotional stimulus. Film-generated emotion was associated with significantly greater increases in activity bilaterally in the occipitotemporparietal cortex, lateral cerebellum, hypothalamus, and a region that includes the anterior temporal cortex, amygdala, and hippocampal formation, suggesting that these regions participate in the emotional response to certain exteroceptive sensory stimuli. Recall-generated sadness was associated with significantly greater increases in activity in the vicinity of the anterior insular cortex, suggesting that this region participates in the emotional response to potentially distressing cognitive or interoceptive sensory stimuli.

CONCLUSIONS

While this study should be considered preliminary, it identified brain regions that participate in externally and internally generated human emotion.

Dynamical energy systems and modern physics: fostering the science and spirit of complementary and alternative medicine

When systems theory is carefully applied to the concept of energy, some novel and far-reaching implications for modern physics and complementary medicine emerge. The heart of systems theory is dynamic interactions: systems do not simply act on systems, they interact with them in complex ways. By definition, systems at any level (e.g., physical, biological, social, ecological) are open to information, energy, and matter to varying degrees, and therefore interact with other systems to varying degrees. We first show how resonance between two tuning forks, a classic demonstration in physics, can be seen to reflect synchronized dynamic interactions over time. We then derive how the dynamic interaction of systems in mutual recurrent feedback relationships naturally create dynamic "memories" for their interactions over time. The mystery of how a photon (or electron) "knows" ahead of time whether to function as a particle or wave in the single slit/double slit quantum physics paradigm is potentially solved when energetic interactions inherent in the experimental system are recognized. The observation that energy decreases with the square of distance is shown not to be immutable when viewed from a dynamical energy systems perspective. Implications for controversial claims in complementary and alternative medicine, such as memory for molecules retained in water (homeopathy), remote diagnosis, and prayer and healing, are considered. A dynamical energy systems framework can facilitate the development of what might be termed "relationship consciousness," which has the potential to nurture both the science and spirit of complementary medicine and might help to create integrated medicine.

Perceptions of parental caring predict health status in midlife: a 35-year follow-up of the Harvard Mastery of Stress Study

OBJECTIVE

This study examined how the perception of parental caring, obtained from undergraduates, relates to subsequent health over the ensuing 35 years.

METHODS

In the early 1950s, initial ratings of parental caring were obtained from a sample of healthy, Harvard undergraduate men who participated in the Harvard Mastery of Stress Study. In a 35 year prospective, follow-up investigation, detailed medical and psychological histories and medical records were obtained.

RESULTS

Subjects identified in midlife as suffering from illnesses such as coronary artery disease, hypertension, duodenal ulcer, and alcoholism, gave their parents significantly lower ratings (p < .00003) on perceived parental caring items (loving, just, fair, hardworking, clever, strong) while in college. This effect was independent of subject's age, family history of illness, smoking behavior, the death and/or divorce of parents, and marital history of subjects. Furthermore, 87% of subjects who rated both their mothers and fathers low in parental caring had diagnosed diseases in midlife, whereas only 25% of subjects who rated both their mothers and fathers high in parental caring had diagnosed diseases in midlife.

CONCLUSIONS

Since parents are usually the most meaningful source of social support for much of early life, the perception of parental caring, and parental loving itself, may have important regulatory and predictive effects on biological and psychological health and illness.

Individual differences in neural sensitization and the role of context in illness from low-level environmental chemical exposures

This paper summarizes the clinical phenomenology of multiple chemical sensitivity (MCS), outlines the concepts and evidence for the olfactory-limbic, neural sensitization model for MCS, and discusses experimental design implications of the model for exposure-related research. Neural sensitization is the progressive amplification of responsivity by the passage of time between repeated, intermittent exposures. Initiation of sensitization may require single toxic or multiple subtoxic exposures, but subsequent elicitation of sensitized responses can involve low or nontoxic levels. Thus, neural sensitization could account for the ability of low levels of environmental chemicals to elicit clinically severe, adverse reactions in MCS. Different forms of sensitization include limbic kindling of seizures (compare temporal lobe epilepsy and simple partial seizures) and time-dependent sensitization of behavioral, neurochemical, immunological, and endocrinological variables. Sensitized dysfunction of the limbic and mesolimbic systems could account in part for many of the cognitive, affective, and somatic symptoms in MCS. Derealization (an alteration in perception making familiar objects or people seem unfamiliar or unreal) is a common MCS symptom and has been linked with limbic dysfunction in clinical neuroscience research. Sensitization is distinct from, but interactive with, other neurobiological learning and memory processes such as conditioning and habituation (compare adaptation or tolerance). In previous studies, hypotheses for MCS involving sensitization, conditioning, and habituation (adaptation) have often been considered in isolation from one another. To design more appropriate chemical exposure studies, it may be important to integrate the various theoretical models and empirical approaches to MCS with the larger scientific literature on individual differences in these potentially interactive phenomena.

Feelings of parental caring predict health status in midlife: a 35-year follow-up of the Harvard Mastery of Stress Study

In the early 1950s, multiple-choice scores reflecting feelings of warmth and closeness with parents were obtained from a sample of healthy, undergraduate Harvard men who participated in the Harvard Mastery of Stress Study. Thirty-five years later, detailed medical and psychological histories and medical records were obtained. Ninety-one percent of participants who did not perceive themselves to have had a warm relationship with their mothers (assessed during college) had diagnosed diseases in midlife (including coronary artery disease, hypertension, duodenal ulcer, and alcoholism), as compared to 45% of participants who perceived themselves to have had a warm relationship with their mothers. A similar association between perceived warmth and closeness and future illness was obtained for fathers. Since parents are usually the most meaningful source of social support in early life, the perception of parental love and caring may have important effects on biological and psychological health and illness throughout life.

Time-dependent sensitization of heart rate and blood pressure over multiple laboratory sessions in elderly individuals with chemical odor intolerance

In this study, we tested the hypothesis that low-level chemical odor intolerance (i.e., "cacosmia") is a manifestation of heightened sensitizability to environmental stimuli. We examined supine heart rate and blood pressure of elderly individuals, who were classified as either having a higher degree of chemical odor intolerance (n = 12) or a lower degree of chemical odor intolerance (n = 13), upon awakening in a sleep research laboratory on 6 different days during an 8-wk protocol. During the 2 initial wk, they consumed a customary baseline diet (including ad lib milk and other dairy products), followed by 3 wk each of nondairy-containing and dairy-containing diets in randomly assigned, counterbalanced order. Measurements were made on 3 pairs of successive days, distributed over a 6-wk period, and on which different diets were consumed. The high-intolerance group had significantly higher mean supine systolic and diastolic blood pressures than did the low-intolerance group. Although subjects consumed milk products during both the initial baseline and subsequent dairy diet periods, the high-intolerance group had significantly higher heart rates and diastolic blood pressures later in the study than at baseline, especially when they were on the dairy diet. In contrast, the cardiovascular measures of the low-intolerance group lowered on average with time. The high-intolerance subjects had an increased mean diastolic blood pressure on the second days versus the first days in the laboratory (averaged across all diets). Collectively, the data suggest that elderly individuals with a high degree of chemical odor intolerance evidence (a) increased sympathetic tone in the cardiovascular system at rest over multiple measurements; and (b) greater sensitizability and/or lesser habituation of heart rate and diastolic blood pressure over time as a function, in part, of repeated environmental stressor exposures (i.e., a novel laboratory contextual setting and/or specific dietary constituents). Consistent with a sensitization model, the findings emphasize the need for two or more identical sessions at least 24 h apart in physiological studies of individuals with a high degree of intolerance for chemical odors versus normal individuals. The results of the blood pressure observations suggest that the possibility of abnormally labile autonomic function and cognitive sequelae in individuals with a high degree of intolerance for chemical odor increases with age.

Elevation of plasma beta-endorphin levels of shy elderly in response to novel laboratory experiences

Heightened psychophysiological reactivity to the novel or unfamiliar is a leading characteristic of sky or behaviorally inhibited individuals. To assess one aspect of the physiological stress response in shyness, the authors compared the morning plasma beta-endorphin levels of 15 extremely sky, healthy elderly individuals with beta-endorphin levels of 15 extremely outgoing persons on three pairs of 2 successive days. The primary finding was that sky participants exhibited significantly higher levels of beta-endorphin on the 1st days of each pair of days, compared with the 2nd days in the laboratory. No main effect for shyness or interaction between shyness and diet on endorphin levels was found. The findings are consistent with a peripheral opioid hyperreactivity to novelty in shy elderly persons. Shyness may constitute a risk factor for panic disorder in younger adults and for nasal allergies and certain cancers in older adults. Experimental design and interpretation of future studies of shy individuals' stress responses may need to consider novelty versus familiarity of the procedures and setting.

Narrative descriptions of parental love and caring predict health status in midlife: a 35-year follow-up of the Harvard Mastery of Stress Study

Perceived social support has been established as an important determinant of mortality risk. The perception of parental love and caring reflects the core of social support in the first 20 years of life. In the early 1950s, narrative descriptions of parents were obtained from a sample of healthy undergraduate men at Harvard University who participated in the Harvard Mastery of Stress Study. In a 35-year prospective follow-up investigation, detailed medical and psychological histories and medical records were obtained. Subjects who had illnesses such as coronary artery disease, hypertension, duodenal ulcer, and alcoholism in midlife had used significantly fewer positive words to describe their parents (eg, loving, friendly, warm, open, understanding, sympathetic, just) while in college. This effect was independent of the subject's age, family history of illness, smoking behavior, marital history, and the death or divorce of the subject's parents. Furthermore, 95% of subjects who used few positive words and also rated their parents low in parental caring had diseases diagnosed in midlife, whereas only 29% of subjects who used many positive words and also rated their parents high in parental caring had diseases diagnosed in midlife. Because parents are usually the most meaningful source of love and caring for much of early life, the perception of parental love and caring may play a special role in promoting long-term health. The findings are consistent with the hypothesis that love and caring play an important role in healing.

Neural sensitization and physiological markers in multiple chemical sensitivity

This paper summarizes the key features of the olfactory-limbic, neural sensitization model for multiple chemical sensitivity (MCS) and presents relevant data on chemically intolerant human subjects from laboratory studies using quantitative electroencephalography, polysomnography, neuropsychological tests, cardiovascular measurements, and blood markers. MCS is a poorly understood chronic, polysymptomatic condition in which some prior controlled research studies have failed to find evidence to differentiate active from placebo tests. Closer examination of past MCS research, however, reveals that studies have failed to incorporate the design and methodological approaches necessary to test for nonimmunological sensitization. Time-dependent sensitization (TDS) is a well-documented phenomenon in the pharmacology literature involving the progressive increase in a given response by the passage of time between the initial and subsequent exposures to a substance or a stressor. As in MCS, multiple, chemically unrelated agents can trigger TDS. Females time-sensitize more readily than do males. Pharmacological and nonpharmacological (stress) stimuli can cross-sensitize. Dopaminergic pathways in the brain and the hypothalamic-pituitary-adrenal axis are likely involved in TDS. Data on the symptomatology of MCS point to central nervous system involvement, including limbic regions that receive input from both olfactory (odor) and trigeminal (irritant) pathways. Limbic and mesolimbic brain regions are among the most sensitizable to repeated, intermittent environmental stimuli. Sensitizable individuals can show no difference or lesser responses to a test substance on initial exposure, but later exhibit much greater increases in responsivity on the next exposure after a period of days. For future research, it is essential to distinguish chemical intolerance symptoms such as derealization, sudden mood changes, musculoskeletal pain, menstrual dysfunction, and uncontrollable sleepiness from chemical phobia and avoidance behaviors. This model permits hypothesis-driven research on MCS and has major implications for interpretation of apparently positive and negative tests for "true" as opposed to "perceived" sensitivity to low levels of environmental chemicals.

A polysomnographic study of sleep disturbance in community elderly with self-reported environmental chemical odor intolerance

Subjective sleep complaints and food intolerances, especially to milk products, are frequent symptoms of individuals who also report intolerance for low-level odors of various environmental chemicals. The purpose of the present study was to evaluate the objective nature of nocturnal sleep patterns during different diets, using polysomnography in community older adults with self-reported illness from chemical odors. Those high in chemical odor intolerance (n = 15) exhibited significantly lower sleep efficiency (p = .005) and lower rapid-eye-movement (REM) sleep percent (p = .04), with a trend toward longer latency to REM sleep (p = .07), than did those low in chemical intolerance (n = 15), especially on dairy-containing as compared with nondairy (soy) diets. The arousal pattern of the chemical odor intolerant group differed from the polysomnographic features of major depression, classical organophosphate toxicity, and subjective insomnia without objective findings. The findings suggest that community elderly with moderate chemical odor intolerance and minimal sleep complaints exhibit objectively poorer sleep than do their normal peers. Individual differences in underlying brain function may help generate these observations. The data support the need for similar studies in clinical populations with chemical odor intolerance, such as multiple chemical sensitivity patients and perhaps certain veterans with "Persian Gulf Syndrome."

Time-dependent sensitization of plasma beta-endorphin in community elderly with self-reported environmental chemical odor intolerance

This study examined plasma beta-endorphin as a marker of the physiological stress response in community elderly who were either high (n = 15) or low (n = 15) in self-rated frequency of illness from environmental chemical odors. Individuals who report nonatopic multiple sensitivities to or intolerances for low levels of environmental chemicals also claim high rates of comorbid food sensitivities or intolerances. Subjects gave 9 AM blood samples for plasma beta-endorphin 90 min after ingesting either 1% fat cow's milk or a soy-based nondairy drink, on six different mornings in the laboratory after all-night sleep recordings. The six sessions-were divided into three sets of two successive days each, with each set [involving baseline (ad lib milk), nondairy (soy-based), and dairy diets] separated from the next by 3 weeks. In the chemically tolerant subjects, stably lower beta-endorphin levels suggested that milk may have been a physiologically less stressful beverage than was the soy drink. In contrast, the chemical odor intolerant group exhibited a) increased levels of plasma beta-endorphin averaged over the 6 days (p = .02); and b) marked fluctuations in endorphin from one laboratory day to the next (Group x Diet x Day interaction, p = .005). The findings were consistent with time-dependent, context-dependent sensitization of beta-endorphin in the chemical odor intolerant individuals.

Impaired verbal and nonverbal emotion recognition in alexithymia

Although clinical observations suggest that alexithymic individuals have a deficit in their ability to recognize emotional stimuli and that this deficit is not simply due to a problem in verbal labeling, these two hypotheses have not been empirically confirmed. Three hundred eighty participants in a community survey without current or past histories of psychiatric disorder completed two independent measures of alexithymia [the Levels of Emotional Awareness Scale (LEAS) and the Toronto Alexithymia Scale (TAS-20)] and the Perception of Affect Task (PAT), a 140-item measure of the ability to match emotion stimuli. The PAT includes four subtasks that require the subject to match verbal or nonverbal emotion stimuli with verbal or nonverbal emotion responses. The subtasks include matching sentences and words (verbal-verbal), faces and words (nonverbal-verbal), sentences and faces (verbal-nonverbal), and faces and photographs of scenes (nonverbal-nonverbal). Across the entire sample, higher (alexithymic) TAS-20 and lower LEAS scores were both correlated with lower accuracy rates on each of the subtasks of the PAT (p < .001), accounting for 10.5% and 18.4% of the variance, respectively. Fifty-one subjects met TAS-20 criteria for alexithymia. Alexithymic individuals scored lower than other subjects on purely nonverbal matching, purely verbal matching, and mixed verbal-nonverbal matching (all p < .001). These results suggest that alexithymia is associated with impaired verbal and nonverbal recognition of emotion stimuli and that the hallmark of alexithymia, a difficulty in putting emotion into words, may be a marker of a more general impairment in the capacity for emotion information processing.

Slowed reaction time performance on a divided attention task in elderly with environmental chemical odor intolerance

Previous research has suggested an association between the subjective report of illness from environmental chemical odors and poorer cognitive task performance in persons with industrial levels of xenobiotic exposures. The present study investigated baseline morning performance on a computerized divided attention task in active retired adults without occupational exposures or clinical disorders who nonetheless rated themselves currently high versus low in episodic illness from the odor of certain environmental chemicals. The chemically intolerant group showed slower reaction times in registering both centrally and peripherally placed stimuli, but no difference in making target tracking errors. Measures of negative affect did not account for these findings. Taken together with evidence for heightened neurobehavioral sensitization in this population, the data suggest disturbances in allocation of attention and related cognitive functions.

Neuropsychiatric and somatic characteristics of young adults with and without self-reported chemical odor intolerance and chemical sensitivity

The psychological, neuropsychiatric, and somatic characteristics of young adults who have different degrees of cacosmia (i.e., feeling "ill" from the odor of xenobiotic chemicals) and who have self-described "chemical sensitivity" were examined. A total of 800 college students completed the following: a self-rating scale for frequency of odor intolerance for 10 common substances, Simon Environmental Illness Symptom Survey, the SCL-90-R, Barsky Amplification Scale, Pearlin-Schooler Mastery Scale, Cheek-Buss and Kagan Shyness scales, Marlowe-Crowne Social Desirability Scale, and a health-symptom and physician-diagnosed checklist. Two pairs of groups were compared: (1) subjects in the top 16% (i.e., cacosmics) and bottom 15% (noncacosmics) of the sample with respect to odor intolerance scale scores; and (2) subjects from the entire sample who did (28%) or did not (72%) consider themselves to be "especially sensitive to certain chemicals.¿ Cacosmics and the chemically sensitive subjects scored significantly higher on measures of psychological distress and amplification of somatic symptoms, but there was little evidence of lifestyle change, as assessed by the Simon Survey. Compared with their respective comparison groups, cacosmic and chemically sensitive groups had significantly higher incidences of illnesses associated with chemicals, alcohol intake, opiate drug use, and caffeine use, even after controlling for the psychological measures and histories of atopic allergy. Subjects with and without neuropsychiatric symptoms were differentiated with respect to chemical odor intolerance, but subjects with and without atopic allergies and possible autoimmune diseases were differentiated with respect to chemical sensitivity. Females were more cacosmic than males. Cacosmia is defined by a population subset, with or without occupational xenobiotic exposures or disability, that has distress and symptom amplification and neuropsychiatric and somatic symptoms, none of which are explained fully by psychological measures. Prospective clinical studies are possible with such individuals. The data are also consistent with a time-dependent sensitization model for illness from low-level chemical exposures.