Social anxiety and response to touch: incongruence between self-evaluative and physiological reactions

Touch is an important form of social interaction, and one that can have powerful emotional consequences. Appropriate touch can be calming, while inappropriate touch can be anxiety provoking. To examine the impact of social touching, this study compared socially high-anxious (N=48) and low-anxious (N=47) women's attitudes concerning social touch, as well as their affective and physiological responses to a wrist touch by a male experimenter. Compared to low-anxious participants, high-anxious participants reported greater anxiety to a variety of social situations involving touch. Consistent with these reports, socially anxious participants reacted to the experimenter's touch with markedly greater increases in self-reported anxiety, self-consciousness, and embarrassment. Physiologically, low-anxious and high-anxious participants showed a distinct pattern of sympathetic-parasympathetic coactivation, as reflected by decreased heart rate and tidal volume, and increased respiratory sinus arrhythmia, skin conductance, systolic/diastolic blood pressure, stroke volume, and respiratory rate. Interestingly, physiological responses were comparable in low and high-anxious groups. These findings indicate that social anxiety is accompanied by heightened aversion towards social situations that involve touch, but this enhanced aversion and negative-emotion report is not reflected in differential physiological responding.

Neurophysiological evidence of corollary discharge dysfunction in schizophrenia

OBJECTIVE

Speaking is hypothesized to generate a corollary discharge of motor speech commands transmitted to the auditory cortex, dampening its response to self-generated speech sounds. Event-related potentials were used to test whether failures of corollary discharge during speech contribute to the pathophysiology of schizophrenia.

METHOD

The N1 component of the event-related potential elicited by vowels was recorded while the vowels were spoken by seven patients with schizophrenia and seven healthy comparison subjects and while the same vowels were played back.

RESULTS

In the healthy subjects, the N1 elicited by spoken vowels was smaller than the N1 elicited by played-back vowels. This reduction in N1 elicited by spoken vowels was not observed in the patients with schizophrenia.

CONCLUSIONS

These findings provide direct neurophysiological evidence for a corollary discharge that dampens sensory responses to self-generated, relative to externally presented, percepts in healthy comparison subjects and its failure in patients with schizophrenia.

Cortical responsiveness during inner speech in schizophrenia: an event-related potential study

OBJECTIVE

The study assessed the effects of inner speech on auditory cortical responsiveness in schizophrenia.

METHOD

Comparison subjects (N=15) and patients with schizophrenia (N=15) were presented with acoustic and visual stimuli during three conditions: while subjects were silent, when spontaneous inner speech might occur; during directed inner speech, while subjects repeated a statement silently to themselves; and while subjects listened to recorded speech. N1 event-related potentials were recorded during the three conditions.

RESULTS

N1 event-related potentials elicited by acoustic stimuli, but not by visual stimuli, were lower during directed inner speech than during the silent baseline condition in the comparison subjects but not in the patients.

CONCLUSIONS

Abnormal auditory cortical responsiveness to inner speech in patients with schizophrenia may be a sign of corollary discharge dysfunction, which may potentially cause misattribution of inner speech to external voices.

Cortical responsiveness during talking and listening in schizophrenia: an event-related brain potential study

BACKGROUND

Failures to recognize inner speech as self-generated may underlie positive symptoms of schizophrenia-like auditory hallucinations. This could result from a faulty comparison in auditory cortex between speech-related corollary discharge and reafferent discharges from thinking or speaking, with misattribution of internal thoughts to external sources. Although compelling, failures to monitor covert speech (thoughts) are not as amenable to investigation as failures to monitor overt speech (talking).

METHODS

Effects of talking on auditory cortex responsiveness were assessed in 10 healthy adults and 12 patients with schizophrenia (DSM-IV) using N1 event-related potentials (ERPs) to acoustic and visual probes during talking aloud, listening to one's speech played back, and silent baseline. Trials contaminated by muscle artifact while talking were excluded.

RESULTS

Talking and listening affected N1 to acoustic but not to visual probes, reflecting modality specificity of effects. Patterns of responses to acoustic probes differed between control subjects and patients. N1 to acoustic probes was reduced during talking compared with baseline in control subjects, but not in patients. Listening reduced N1 equivalently in both groups.

CONCLUSIONS

Although the failure of N1 to be reduced during talking was not related to current hallucinations in patients, it may be related to the potential to hallucinate.

Characteristics of worry in GAD patients, social phobics, and controls

Phenomenological features of worry such as thought content, subjective experience of worry, and efforts to control were investigated in the present interview study, as well as retrospective information about possible origins. To examine the clinical specificity of worrying in Generalized Anxiety Disorder (GAD), 36 GAD patients were compared to a normal control group (N = 30) and to a clinical control group (N = 22 social phobics). GAD patients differed from both groups in having higher frequency of worry, higher number of different worry topics, lower subjective controllability, more accompanying bodily symptoms, and more distress during worry. Thus, in general, our data confirm the central and specific role of worrying in GAD. Furthermore, in contrast to other topics, worrying about daily hassles was specific to GAD patients, which represents a lower threshold for starting to worry.

Respiratory dysregulation in anxiety, functional cardiac, and pain disorders. Assessment, phenomenology, and treatment

Respiration is a complex physiological system affecting a variety of physical processes that can act as a critical link between mind and body. This review discusses the evidence for dysregulated breathing playing a role in three clinical syndromes: panic disorder, functional cardiac disorder, and chronic pain. Recent technological advances allowing the ambulatory assessment of endtidal partial pressure of CO2 (PCO2) and respiratory patterns have opened up new avenues for investigation and treatment of these disorders. The latest evidence from laboratories indicates that subtle disturbances of breathing, such as tidal volume instability and sighing, contribute to the chronic hypocapnia often found in panic patients. Hypocapnia is also common in functional cardiac and chronic pain disorders, and studies indicate that it mediates some of their symptomatology. Consistent with the role of respiratory dysregulation in these disorders, initial evidence indicates efficacy of respiration-focused treatment.

Respiratory biofeedback-assisted therapy in panic disorder

The authors describe a new methodologically improved behavioral treatment for panic patients using respiratory biofeedback from a handheld capnometry device. The treatment rationale is based on the assumption that sustained hypocapnia resulting from hyperventilation is a key mechanism in the production and maintenance of panic. The brief 4-week biofeedback therapy is aimed at voluntarily increasing self-monitored end-tidal partial pressure of carbon dioxide (PCO2) and reducing respiratory rate and instability through breathing exercises in patients' environment. Preliminary results from 4 patients indicate that the therapy was successful in reducing panic symptoms and other psychological characteristics associated with panic disorder. Physiological data obtained from home training, 24-hour ambulatory monitoring pretherapy and posttherapy, and laboratory assessment at follow-up indicate that patients started out with low resting PCO2 levels, increased those levels during therapy, and maintained those levels at posttherapy and/or follow-up. Partial dissociation between PCO2 and respiratory rate questions whether respiratory rate should be the main focus of breathing training in panic disorder.

Blushing and physiological arousability in social phobia

Blushing is the most prominent symptom of social phobia, and fear perception of visible anxiety symptoms is an important component of cognitive behavioral models of social phobia. However, it is not clear how physiological and psychological aspects of blushing and other somatic symptoms are linked in this disorder. The authors tested whether social situations trigger different facial blood volume changes (blushing) between social phobic persons with and without primary complaint of blushing and control participants. Thirty social phobic persons. 15 of whom were especially concerned about blushing, and 14 control participants were assessed while watching an embarrassing videotape, holding a conversation, and giving a talk. Only when watching the video did the social phobic persons blush more than controls blushed. Social phobic persons who complained of blushing did not blush more intensely than did social phobic persons without blushing complaints but had higher heart rates, possibly reflecting higher arousability of this subgroup.

The somatic symptom paradox in DSM-IV anxiety disorders: suggestions for a clinical focus in psychophysiology

Although DSM-IV criteria for anxiety disorders include physiological symptoms, these symptoms are evaluated exclusively by verbal report. The current review explores the background for this paradox and tries to demonstrate on theoretical and empirical grounds how it could be resolved, providing new insights about the role of psychophysiological measures in the clinic. The three-systems approach to evaluating anxiety argues that somatic measures as well as verbal and behavioral ones are indispensable. However, the low concordance between these domains of measurement impugns their reliability and validity. We argue that concordance can be improved by examining the relationship of variables less global than anxiety and by restriction to specific anxiety disorders. For example, recent evidence from our and other laboratories indicate a prominent role of self-reported and physiologically measured breathing irregularities in panic disorder. Nonetheless, even within a diagnosis, anxiety patients vary radically in which somatic variables are deviant. Thus, in clinical practice, individual profiles of psychological and physiological anxiety responses may be essential to indicate distinct therapeutic approaches and ways of tracking improvement. Laboratory provocations specific to certain anxiety disorders and advances in ambulatory monitoring vastly expand the scope of self-report and physiological measurement and will likely contribute to a refined assessment of anxiety disorders.

Slow recovery from voluntary hyperventilation in panic disorder

OBJECTIVE

Because hyperventilation has figured prominently in theories of panic disorder (PD) but not of social phobia (SP), we compared predictions regarding diagnosis-specific differences in psychological and physiological measures before, during, and after voluntary hyperventilation.

METHOD

Physiological responses were recorded in 14 patients with PD, 24 patients with SP, and 24 controls during six cycles of 1-minute of fast breathing alternating with 1 minute of recovery, followed by 3 minutes of fast breathing and 10 minutes of recovery. Speed of fast breathing was paced by a tone modulated at 18 cycles/minute, and depth by feedback aimed at achieving an end-tidal pCO2 of 20 mm Hg. These values were reached equally by all groups.

RESULTS

During fast breathing, PD and SP patients reported more anxiety than controls, and their feelings of dyspnea and suffocation increased more from baseline. Skin conductance declined more slowly in PD over the six 1-minute fast breathing periods. At the end of the final 10-minute recovery, PD patients reported more awareness of breathing, dyspnea, and fear of being short of breath, and their pCO2s, heart rates, and skin conductance levels had returned less toward normal levels than in other groups. Their lower pCO2s were associated with a higher frequency of sigh breaths.

CONCLUSIONS

PD and SP patients report more distress than controls to equal amounts of hypocapnia, but PD differ from SP patients and controls in having slower symptomatic and physiological recovery. This finding was not specifically predicted by hyperventilation, cognitive-behavioral, or suffocation alarm theories of PD.

The emotional Stroop effect in anxiety disorders: general emotional or disorder specificity?

Selective attentional biases, often documented with a modified Stroop task, are considered to play an important role in the etiology and maintenance of anxiety. Two competing explanations for these effects are selectivity for highly emotional words in general vs. selectivity for disorder-specific words. We tested these explanations in 32 patients with generalized anxiety disorder (GAD), 29 patients with social phobia (SP), and 31 non-anxious controls. Stimuli were of four kinds: GAD-related words, SP-related words, words with a neutral valence, and words with a positive valence. Different attentional biases were observed: GAD patients were slowed by all types of emotional words, while SP patients were distracted specifically by speech-related words.

Characteristics of sighing in panic disorder

BACKGROUND

Sighs, breaths with larger tidal volumes than surrounding breaths, have been reported as being more frequent in patients with anxiety disorders.

METHODS

Sixteen patients with panic disorder, 15 with generalized anxiety disorder, and 19 normal control subjects were asked to sit quietly for 30 min. Respiratory volumes and timing were recorded with inductive plethysmography and expired pCO(2), from nasal prongs.

RESULTS

Panic disorder patients sighed more and had tonically lower end-tidal pCO(2)s than control subjects, whereas generalized anxiety disorder patients were intermediate. Sighs defined as >2.0 times the subject mean discriminated groups best. Sigh frequency was more predictive of individual pCO(2) levels than was minute volume. Ensemble averaging of respiratory variables for sequences of breaths surrounding sighs showed no evidence that sighs were triggered by increased pCO(2) or reduced tidal volume in any group. Sigh breaths were larger in panic disorder patients than in control subjects. After sighs, pCO(2) and tidal volume did not return to baseline levels as quickly in panic disorder patients as in control subjects.

CONCLUSIONS

Hypocapnia in panic disorder patients is related to sigh frequency. In none of the groups was sighing a homeostatic response. Panic disorder patients show less peripheral chemoreflex gain than control subjects, which would maintain low pCO(2) levels after sighing.

Physiologic instability in panic disorder and generalized anxiety disorder

BACKGROUND

Because panic attacks can be accompanied by surges in physiologic activation, we tested the hypothesis that panic disorder is characterized by fluctuations of physiologic variables in the absence of external triggers.

METHODS

Sixteen patients with panic disorder, 15 with generalized anxiety disorder, and 19 normal control subjects were asked to sit quietly for 30 min. Electrodermal, cardiovascular, and respiratory measures were analyzed using complex demodulation to quantify variability in physiologic indices.

RESULTS

Both patient groups reported equally more anxiety and cardiac symptoms than control subjects, but certain other somatic symptoms, including breathlessness, were elevated only in panic disorder patients. Mean end-tidal pCO(2) and respiratory rates were lower, and tidal volume and the number of sighs were higher in panic disorder patients than control subjects. Neither cardiovascular (heart rate, arterial pressure, cardiac output), nor electrodermal instability including sighs distinguished the groups; however, tidal volume instability was greater in panic disorder than generalized anxiety disorder patients or control subjects. Several other respiratory measures (pCO(2), respiratory rate, minute volume, duty cycle) showed greater instability in both patient groups than in control subjects.

CONCLUSIONS

Respiration is particularly unstable in panic disorder, underlining the importance of respiratory physiology in understanding this disorder. Whether our findings represent state or trait characteristics is discussed.

Analysis of cardiovascular regulation

Adequate characterization of hemodynamic and autonomic responses to physical and mental stress can elucidate underlying mechanisms of cardiovascular disease or anxiety disorders. We developed a physiological signal processing system for analysis of continuously recorded ECG, arterial blood pressure (BP), and respiratory signals using the programming language Matlab. Data collection devices are a 16-channel digital, physiological recorder (Vitaport), a finger arterial pressure transducer (Finapres), and a respiratory inductance plethysmograph (Respitrace). Besides the conventional analysis of the physiological channels, power spectral density and transfer functions of respiration, heart rate, and blood pressure variability are used to characterize respiratory sinus arrhythmia (RSA), 0.10-Hz BP oscillatory activity (Mayer-waves), and baroreflex sensitivity. The arterial pressure transducer waveforms permit noninvasive estimation of stroke volume, cardiac output, and systemic vascular resistance. Time trends in spectral composition of indices are assessed using complex demodulation. Transient dynamic changes of cardiovascular parameters at the onset of stress and recovery periods are quantified using a regression breakpoint model that optimizes piecewise linear curve fitting. Approximate entropy (ApEn) is computed to quantify the degree of chaos in heartbeat dynamics. Using our signal processing system we found distinct response patterns in subgroups of patients with coronary artery disease or anxiety disorders, which were related to specific pharmacological and behavioral factors.

Blushing and physiological arousability in social phobia

Blushing is the most prominent symptom of social phobia, and fear perception of visible anxiety symptoms is an important component of cognitive behavioral models of social phobia. However, it is not clear how physiological and psychological aspects of blushing and other somatic symptoms are linked in this disorder. The authors tested whether social situations trigger different facial blood volume changes (blushing) between social phobic persons with and without primary complaint of blushing and control participants. Thirty social phobic persons. 15 of whom were especially concerned about blushing, and 14 control participants were assessed while watching an embarrassing videotape, holding a conversation, and giving a talk. Only when watching the video did the social phobic persons blush more than controls blushed. Social phobic persons who complained of blushing did not blush more intensely than did social phobic persons without blushing complaints but had higher heart rates, possibly reflecting higher arousability of this subgroup.

Psychophysiological assessment: clinical applications for PTSD

Descriptions of anxiety disorders clearly recognize the physiological features of anxiety, yet in most clinical practice and research there is little actual use of physiological measurement. This is unfortunate because a potentially important source of information is thereby unavailable and is likely to result in judgements about emotional experience that are less accurate, complete, and reliable than those that include physiological information. The neglect of physiological measures may result from a variety of concerns regarding test attributes such as reliability, validity, utility, and complexity. Promising results from studies of posttraumatic stress disorder (PTSD) demonstrate that physiological assessment can provide valuable clinical and theoretical insight. Numerous studies have now shown that heightened physiological reactivity to trauma-related cues is highly indicative of a diagnosis of PTSD. Physiological tests have achieved some success in predicting the development and persistence of PTSD, and in predicting and assessing treatment response. Studies of the startle response, aversive conditioning, and brain potentials during cognitive processing have identified several potentially important differences between PTSD patients and controls. This paper provides an overview of psychophysiological findings in PTSD and considers potential clinical applications of psychophysiological assessment for this disorder.

Failures of automatic and strategic processing in schizophrenia: comparisons of event-related brain potential and startle blink modification

Noises elicit startle blinks that are inhibited when immediately (approximately 100 ms) preceded by non-startling prepulses, perhaps reflecting automatic sensory gating. Startle blinks are facilitated when preceded by prepulses at longer lead intervals, perhaps reflecting strategic processes. Event-related brain potentials (ERPs) and startle blinks were used to investigate the well-documented prepulse inhibition failure in schizophrenia. Blinks and ERPs were recorded from 15 schizophrenic men and 20 age-matched controls to noises alone and to noises preceded by prepulses at 120 (PP120), 500 (PP500) and 4000 ms (PP4000) lead intervals. Neither blinks nor any of the ERP components elicited by the noise alone differentiated schizophrenics from controls, although responses to noises were modified by prepulses differently in the two groups. With the N1 component of the ERP, patients showed normal inhibition but lacked facilitation, and with P2, patients lacked inhibition, but showed normal facilitation. With reflex blinks and P300, inhibition was seen in both groups, but no facilitation. These results suggest that different neural circuits are involved in blink and cortical reflections of startle modification in schizophrenics and controls, with both automatic and strategic processes being impaired in schizophrenia.

Explicit memory in anxiety disorders

Two experiments were conducted to study selective memory bias favoring anxiety-relevant materials in patients with anxiety disorders. In the 1st experiment, 32 patients with generalized anxiety disorder (GAD), 30 with social phobia (speaking anxiety), and 31 control participants incidentally learned GAD-relevant words, speech anxiety-relevant words, strongly pleasant words, and words with a neutral valence. Participants did not show any explicit memory bias for threatening materials. Thirty patients suffering from panic disorder (PD) with agoraphobia and 30 controls took part in the 2nd experiment. The design was similar to the 1st experiment. This time a highly specific selective memory bias for threatening words was found. Words describing symptoms of anxiety were better recalled by PD patients. Results are consistent with previous findings but are inexplicable by existing theories.

Explicit memory in anxiety disorders

Two experiments were conducted to study selective memory bias favoring anxiety-relevant materials in patients with anxiety disorders. In the 1st experiment, 32 patients with generalized anxiety disorder (GAD), 30 with social phobia (speaking anxiety), and 31 control participants incidentally learned GAD-relevant words, speech anxiety-relevant words, strongly pleasant words, and words with a neutral valence. Participants did not show any explicit memory bias for threatening materials. Thirty patients suffering from panic disorder (PD) with agoraphobia and 30 controls took part in the 2nd experiment. The design was similar to the 1st experiment. This time a highly specific selective memory bias for threatening words was found. Words describing symptoms of anxiety were better recalled by PD patients. Results are consistent with previous findings but are inexplicable by existing theories.

Voluntary breath holding in panic and generalized anxiety disorders

OBJECTIVE

Because breath holding causes arterial pCO2 to increase, we used it to test the hypothesis that in panic disorder (PD) a biological suffocation monitor is pathologically sensitive.

METHOD

Nineteen patients with PD, 17 with generalized anxiety disorder (GAD), and 22 normal controls took deep breaths on signal and held them until a release signal was given 30 seconds later. This was repeated 12 times separated by 60-second normal breathing periods.

RESULTS

PD patients reported having had in the past more symptoms of shortness of breath when anxious, and more frequent frightening suffocation experiences than the other groups. However, increases in self-rated anxiety between periods of normal breathing and periods of breath holding were similar in all three groups. Skin conductance, blood pressure, and T-wave amplitude reactions to breath holdings were also similar, but heart rate acceleration upon taking a deep breath was greater in GAD patients. Before and after individual breath holdings, end-tidal pCO2 was lower in PD patients than in normal controls; GAD patients were intermediate. Inspiratory flow rate did not differ between groups.

CONCLUSIONS

Our physiological results provide no direct support for an overly sensitive suffocation alarm system in PD. Lower pCO2 may be due to anxiety causing hyperventilation in patients prone to panic.

Taking the laboratory to the skies: ambulatory assessment of self-report, autonomic, and respiratory responses in flying phobia

We evaluated the feasibility of recording multiple physiological anxiety measures during a flight and how well they could distinguish flight phobics from controls. Benefits of baseline adjustment and transformation for all variables and adjustment of heart rate by ventilation to give additional heart rate were calculated. Effect size, one measure of the power to discriminate groups, was between 1.1 and 1.7 for heart rate measures. Although respiratory rate and minute ventilation, indicators of hyperventilation, did not differ between groups, phobics paused more during inspiration than did controls. Phobics also showed more skin conductance fluctuations and less respiratory sinus arrhythmia. Self-reported anxiety was a more powerful discriminator than physiological measures, a result that may be partially explained by how phobics were selected. These results indicate that monitoring of multiple physiological systems outside the laboratory is practical and informative. Physiological measures of psychological importance can be quantified accurately in a noisy, changing, unsupervised ambulatory setting.

Using minute ventilation for ambulatory estimation of additional heart rate

Both physical activity and emotion produce physiological activation. The emotional component of heart rate (HR) can be estimated as the additional HR (aHR) above that predicted by O2 consumption. Our innovation was to substitute minute ventilation (V) for O2 consumption, calculating aHR from individual relations between V and HR during an exercise test. We physiologically monitored 28 flight phobics and 15 non-anxious controls while walking (leaving the hospital, entering a plane), and during a commercial flight. Raw HR did not differ between phobics and controls when leaving the hospital (118/114 bpm) or entering the plane (117/110 bpm). However, although aHR was not different when leaving the hospital (7.0/8.6 bpm), it was significantly greater when entering the plane (17.5/9.9 bpm), accurately reflecting the increased subjective anxiety of the phobics. V was not higher in phobics than controls during any condition, suggesting an absence of hyperventilation in the phobics. The results demonstrate the utility of our method for analyzing HR in people whose stress occurs when they are physically active.

Autonomic instability during relaxation in panic disorder

The ability to relax was assessed in 14 patients with panic disorder (PD) and 15 non-anxious control subjects for 10 min. Before and after relaxation, subjects performed a standardized activating task of talking continuously for 4 min. The fractional decline in reported anxiety, tension, and alertness between the first talking period and the relaxation minimum did not differ between groups, although absolute levels of anxiety and tension were higher for PD patients. The fractional decline in skin conductance between the first talking period and the last minute of relaxation was less for PD patients than control subjects, while their increase in skin temperature was greater. Skin conductance showed a linear decline over the logarithm of relaxation time, the slope of which was less steep for PD patients. Goodness of fit of skin conductance over log time was also significantly poorer for PD patients. Heart rate levels or slopes did not differ between groups. Autonomic differences between PD and control subjects were largely due to six patients who reported having panic attacks during the test and higher pretest anxiety levels. In conclusion, indicators of relaxation were inconsistent. Skin conductance suggested autonomic instability during quiet sitting in patients who panic or who are prone to panic.

Don't worry and beware of white bears: thought suppression in anxiety patients

The ability to suppress unwanted thoughts was investigated in patients with Generalized Anxiety Disorder (GAD; n = 29), Speech Phobics (n = 25), and nonanxious controls (n = 28). All participants spent 5 minutes thinking aloud about anything that came to mind while trying not to think of white bears. In another task, they thought aloud for 5 minutes while trying not to think of their main worry. Intrusions of unwanted thoughts were signaled by button presses and recorded on tape. In accordance with the disorder's definition and complaints of the GAD patients, they showed more intrusions of their main worry than of white bears. The opposite was true for other participants. Compared to a baseline measure, all participant groups were unable to reduce duration of main worry thoughts when trying to suppress them.

Speech disturbances and gaze behavior during public speaking in subtypes of social phobia

Twenty-four social phobics with public speaking anxiety and 25 nonphobic individuals (controls) gave a speech in front of two people. Subjective anxiety, gaze behavior, and speech disturbances were assessed. Based on subjects' fear ratings of social situations, phobics and controls were divided into the generalized and nongeneralized subtype. Results showed that generalized phobics reported the most, and nongeneralized controls the least anxiety during public speaking. All subjects had longer and more frequent eye contact when delivering a speech than when talking with an experimenter or sitting in front of an audience. Phobics showed more filled pauses, had longer silent pauses, paused more frequently, and spent more time pausing than controls when giving a speech. Generalized phobics spent more time pausing during their speech than the other subgroups (nongeneralized controls, generalized controls, and nongeneralized phobics). These results suggest that generalized phobics tended to shift attentional resources from speech production to other cognitive tasks.

Acute and delayed effects of alprazolam on flight phobics during exposure

In order to test if a benzodiazepine would enhance or hinder the therapeutic effects of exposure, immediate and delayed effects of alprazolam on flight phobics were assessed by questionnaires and ambulatory physiological recording. Physiological measures included heart rate, skin conductance level and fluctuations, finger temperature, respiratory sinus arrhythmia, and various respiratory measures derived from two bands calibrated for each subject. Twenty-eight women with flying phobia flew twice at a 1-week interval. One and a half hours before flight 1, 14 randomly assigned phobics received double-blind 1 mg of alprazolam and 14 received placebo. On flight 1, alprazolam reduced self-reported anxiety (5.0 vs 7.4) and symptoms (5.3 vs 3.6) more than placebo, but induced an increase in heart rate (114 vs 105 bpm) and respiratory rate (22.7 vs 18.3 breaths/min). Before flight 2, the alprazolam group did not expect to be more anxious than the placebo group (6.7 vs 6.5), but in fact indicated more anxiety during flight (8.5 vs 5.6), and a substantial increase in panic attacks from flight 1 to flight 2 (7% vs 71%). Heart rates in the alprazolam group increased further (123 bpm). Results indicate that alprazolam increases physiological activation under acute stress conditions and hinders therapeutic effects of exposure in flying phobia.

Clinical characteristics of flight phobia

Sixty-six subjects with severe fear of flying were recruited by advertisement and compared to 21 controls without flying fears. Subjects were interviewed and given several questionnaires to determine DSM-III-R diagnoses, history of flying, and development and course of flying phobia. Our phobic sample had a mean age of 46 and was 89% female. Diagnostically, 27% met criteria for current Panic Disorder with Agoraphobia, and 17% criteria for that diagnosis in the past. These two groups were more concerned with internal or social anxiety stimuli during flight than the group who had never had panic attacks but met criteria for Simple Phobia (flying). All three groups were equally concerned about external dangers. Traumatic flight events were common in phobics and controls, but phobics reported reacting to these events more strongly. Our results suggest a vulnerability-stress model with several vulnerability factors, including cognitive ones. Treatment implications are discussed.

Automatic and effortful processing in aging and dementia: event-related brain potentials

Automatic and effortful processes were investigated using event-related brain potentials (ERPs) recorded from moderately impaired subjects with probable Alzheimer's Disease (AD), normal elderly, and normal young controls. The effects of effortful attention on ERPs to loud noises and the effects of stimulus intrusiveness on effortfully elicited ERPs were studied. First, ERPs to task relevant and irrelevant startling noises were compared. Second, ERPs to startling noises and moderate tones were compared when both were targets. The effects of age (young vs. elderly controls) and effects of dementing disease (AD subjects vs. elderly controls) were also assessed. Effortful attention augmented noise-elicited P300 amplitude in elderly subjects, but not in young. Intrusiveness augmented task-relevant P300 amplitude in young subjects, but not in elderly. Neither variable affected P300 amplitude in AD subjects. Thus, effects of age and disease depended on how P300 was elicited: when effortfully elicited, P300 amplitude was affected by disease but not age; when automatically elicited, P300 amplitude was affected by age but not disease. N1 effects differed from P300 effects.

N400 evidence of abnormal responses to speech in Alzheimer's disease

The status of semantic priming in Alzheimer's disease (AD) was examined using the speech elicited N400 component of the event-related brain potential (ERP). Speech was naturally paced, with 1 s of silence before the final word. In the semantic task, subjects attended to the meaning of the sentences for a subsequent memory test. In the phonemic monitoring task, they counted the words beginning with the letter 'p'. The effects of age were assessed by comparing young and elderly, and the effects of disease by comparing elderly and AD subjects. In healthy young and elderly subjects, N400s were large to semantically unprimed words and small to semantically primed words. In AD subjects, N400s were large to primed words, reflecting a failure of the sentence stem to prime the final word, and probably an impairment in semantic knowledge. The N400 priming effect was not smaller during the phonemic than semantic task in any group, suggesting that the semantic qualities of speech are processed even when subjects are attending to phonemic qualities. N400 latency was delayed with age and further delayed with dementia.

Activation in novice and expert parachutists while jumping

Heart and respiration rates were measured ambulatorily in 16 novice and 25 expert (> 380 delayed free-fall jumps) sports parachutists while making a static-line jump. Self-reported anxiety and heart rate peaked near the point of jumping in both groups rather than earlier in experts, as reported by Fenz and Epstein (1967, Psychosomatic Medicine, 29, 33-51). While sitting in the airplane 1 min before exit, mean heart rate was 124 bpm in novices and 102 in experts and increased during jumping to 170 and 145, respectively. The almost identical rise in the two groups could be accounted for largely by physical exertion, replicated with jumps from a training model on the ground. Exercise testing at a different location showed that experts were more fit. Respiration rate was higher in the airplane than at baselines, especially for novices. In conclusion, our results are more compatible theoretically with extinction of anticipatory anxiety than with learned anxiety inhibition.

Conditioning theory: a model for the etiology of public speaking anxiety?

To study the etiology of public speaking anxiety (speech phobia), 30 Ss with the fear of public speaking, and 24 controls without this fear were asked about past public speaking experiences, their beliefs about the main reason for their phobia, and their concerns in the feared situation. All speech phobics met the DSM-III-R criteria for social phobia. Results showed that traumatic external events, vicarious and informational learning--the causes for phobia that fit in best with Rachman's conditioning theory--were notably uncommon among these phobics, who attributed their fear most often to panic attacks. Yet it was not clear whether panic attacks were causes or consequences of phobia.

Psychophysiological differences between subgroups of social phobia

Individuals meeting criteria of the revised third edition of Diagnostic and Statistical Manual for Mental Disorders (American Psychiatric Association, 1987) for social phobia with a fear of speaking in front of people were subdivided into those with (n = 16) and without (n = 14) avoidant personality disorder (APD). These individuals and nonanxious controls (n = 22) spoke in front of a small audience while speaking time, subjective anxiety, fearful thoughts, and electrocardiographic and respiratory measures were recorded. Controls spoke for longer than either social phobia group. Those with social phobia and APD reported more subjective anxiety and more fear cognitions than the other two groups; phobic individuals without APD showed greater heart rates in the phobic situation than either social phobics with APD or controls. The latter two groups did not differ in heart rate. These results indicate incongruent subjective and heart rate responses to the feared situation. A similar pattern of results was found when participants were divided into generalized and specific social phobia groups.

Elderly men and women are less responsive to startling noises: N1, P3 and blink evidence

Previously we observed that the P3 component of the event-related brain potential (ERP) elicited by startling noises, and to a lesser extent P3 to target tones, is reduced in the elderly (Ford & Pfefferbaum, 1991). In the current experiment, we tried to eliminate possible effects of age-related hearing deficits on the responses to noises by filtering them to include only frequencies heard best by the elderly (0-1000 Hz) and by setting noise intensity relative to each subject's threshold (sensation level, SL). Twelve younger (mean 22 years) and 12 older (mean 69 years) men and women listened to three sequences of tones (80%, 500 Hz, 70 dB SPL) and noises (20%). One type of noise occurred in each sequence (wide band noise set to 107 dB SPL, narrow band noise set to 107 dB SPL, or narrow band noise set to approximately 65 dB SL). The order of the three sequences was counterbalanced across age and sex. Younger subjects blinked to the noise 4-5 times more often than older subjects and had N1 and P3 amplitudes that were 2-3 times larger, regardless of the noise type. N1 amplitude to the background frequent tones and non-startle blinks did not differ between groups. Thus, even when noises were narrow band and set relative to each subject's threshold, older subjects were less responsive to startling auditory stimuli than were younger.

ERPs for infrequent omissions and inclusions of stimulus elements

A negative event-related potential (ERP) wave called mismatch negativity (MMN) is elicited by an infrequent deviant stimulus in a sequence of frequent standard stimuli. Omission of a stimulus in a sequence of stimuli, however, has been considered to elicit a negativity different from MMN. The present study addressed this issue by examining ERPs for infrequent omissions and inclusions of compound stimuli or their elements. Three kinds of stimuli were presented: a 1000-Hz sine wave tone (Sine), white noise with the 1000-Hz frequency sharply filtered out (Noise), and a composite of the pure tone and the filtered white noise (SiNoise). All stimuli had 50 ms duration and were presented with a regular interstimulus interval of 650 ms. Intensities were 75 dB SPL for the tone and noise stimuli and slightly higher for the composite stimulus. The three kinds of stimuli were presented on separate runs, either as the frequent stimulus or one of two infrequent stimuli, each with 10% probability. Infrequent omission of the large stimulus element (Sine deviant to SiNoise) tended to elicit later MMN than inclusion of the same element (SiNoise deviant to Sine). Omission of the small stimulus element (Noise deviant to SiNoise) elicited a smaller and later MMN than did inclusion of the same element (SiNoise deviant to Noise). These data suggest that MMNs are also elicited by partial stimulus omissions, although they seem to be more sensitive to other kinds of stimulus deviances.

ERPs in schizophrenia: effects of antipsychotic medication

Thirty unmedicated schizophrenics were compared to 29 age-matched controls on auditory and visual event-related brain potential (ERP) paradigms. Twenty-one of these patients were tested again after 1 week on placebo and after 4 weeks on antipsychotic medication. Before treatment, N1, N2, and P3 components of the auditory ERP were smaller in the schizophrenics than in the controls. Although visual N2 was smaller in schizophrenics, visual P3 was not. In spite of significant clinical improvement with antipsychotic treatment, amplitudes of auditory and visual N1, N2, and P3 were not significantly changed. Higher blood levels of antipsychotic medication were related to reductions in auditory P3 latency, however. In addition, higher levels of cerebrospinal fluid (CSF) MHPG (methoxyhydroxyphenylglycol) were associated with larger auditory N1s and larger auditory and visual P3s, suggesting an influence of arousal on these components in schizophrenics. In spite of this influence, reduction of the auditory P3 in schizophrenia is an enduring trait of the disease, which is not affected by antipsychotic medication or clinical improvement.

Stress test reactivity in panic disorder

The psychological and physiological reactivity of 52 patients with panic disorder to mental arithmetic, cold pressor, and 5% carbon dioxide inhalation tests was compared with that of 26 age- and sex-matched normal subjects. In general, patients with panic disorder were neither more physiologically reactive to these stressors than normal subjects nor slower to recover from them, but they were tonically more anxious and much more likely to ask to stop carbon dioxide inhalation or to report panic attacks during this test. Patients who reported panic attacks (46%) had manifested greater anticipatory anxiety before the gas was delivered, accompanied with increased beta-adrenergic cardiac tone. Thus, anticipatory anxiety can be an important factor in panic provocation. Physiological measures varied greatly in their sensitivity to phasic or tonic anxiety. Carbon dioxide stimulated large increases in respiratory minute volume, but these increases were no greater for patients than for normal subjects.

Guidelines for reducing the risk of disease transmission in the psychophysiology laboratory. SPR Ad Hoc Committee on the Prevention of Disease Transmission

The acquired immunodeficiency syndrome (AIDS) pandemic has highlighted the need for safeguards against the inadvertent transmission of infectious disease in the psychophysiology laboratory. These Guidelines identify factors contributing to the risk of bloodborne disease transmission to subjects or technicians, and recommend procedures to minimize such risk, given current knowledge and techniques. The lowest risk is associated with the application of devices, such as surface electrodes, to nonabraded, intact skin. Such devices should be clean, but do not require disinfection. The potential risk of infection is higher when surface electrodes are applied to non-intact skin. Abrasion, or other breaks in the skin, can allow seepage of blood products carrying such pathogens as hepatitis B virus and the human immunodeficiency virus that causes AIDS. Thus electrodes require high-level disinfection before reuse on non-intact skin. In addition, technicians should wear gloves during skin preparation and should abrade the skin no more than necessary, using only sterile, preferably non-sharp materials. The highest risk is that associated with items that enter sterile tissue, such as subdermal electrodes and the needles and lancets sometimes used in skin preparation. Such items must be sterile at the time of use and must be handled with extreme caution.

Imipramine and alprazolam effects on stress test reactivity in panic disorder

The reactivity of 40 panic disorder patients on mental arithmetic, cold pressor, and 5% CO2 inhalation stressors was tested before and after 8 weeks of treatment with imipramine, alprazolam, or placebo. Mean levels of subjective and physiological stress measures were compared during a baseline before any stressors were given, and at anticipation, stressor, and recovery periods for each stressor. After treatment, imipramine patients differed from the other two treatment groups on the prestressor baseline in showing higher systolic blood pressure (mean difference about 10 mmHg), higher diastolic blood pressure (10 mm Hg), higher heart rate (15 bpm), less respiratory sinus arrhythmia, shorter pulse transit time, and lower T-wave amplitude. Respiratory measures, electrodermal measures, body movement, and self-reported anxiety and excitement did not distinguish the groups. Reactivity to the stress tests was unaffected by the medications, but tonic differences present in the baseline persisted.

Auditory event-related potentials and electrodermal activity in medicated and unmedicated schizophrenics

Event-related potentials (ERPs) and electrodermal activity were studied in 14 medicated schizophrenics, 17 unmedicated schizophrenics, and 23 age- and education-matched controls. Subjects were run in three auditory stimulus paradigms differing from the usual ERP paradigms in having interstimulus intervals greater than 12 sec to permit measurement of the longer latency skin conductance response (SCR). In every paradigm medicated but not unmedicated schizophrenics had smaller N120 amplitudes and fewer SCRs than controls. In addition, medicated schizophrenics showed reduced P200 amplitude and latency, longer P320 latency, and reduced skin conductance levels in certain paradigms. These effects cannot easily be attributed to different mental states of medicated and unmedicated patients, since their Brief Psychiatric Rating Scale scores were almost the same. It is more probable that antipsychotic and antiparkinsonian drugs reduced electrodermal activity through anticholinergic mechanisms and that the antipsychotic drugs attenuated N120 through other biological mechanisms.

Effect of two beta-blockers on stress during mental arithmetic

Heart rate, blood pressure, and subjective stress ratings were recorded from 36 healthy normotensive students at three points in time: during a drug-free baseline, during a baseline 2 h after ingesting single oral doses of atenolol (75 mg), metoprolol (150 mg), or lactate placebo, and during a subsequently administered mental arithmetic test. Both beta-blockers equally reduced baseline heart rate and heart rate response to arithmetic, but subjective stress rating increases to arithmetic were greater for atenolol than for placebo and metoprolol. These results are contrary to peripheral theories of anxiety regulation. While the hydrophilic atenolol barely penetrates the blood-brain barrier, the lipophilic metoprolol can exert direct CNS effects in addition to its peripheral actions. Central stress-dampening effects of lipophilic beta-blockers may override peripheral baroreceptor-mediated stress-promoting effects.

Skin conductance habituation in panic disorder patients

Skin conductance habituation was compared between 38 patients meeting DSM-III criteria for Panic Disorder and 29 normal controls. Approximately half of each group was randomly assigned to be given 100 dB SPL tones and the other half 75 dB tones. All indices pointed to slowed habituation in patients compared with normals: number of trials to response habituation, total number of responses, and slope of decline of skin conductance level. Patient-normal differences were not significantly larger for 100 dB than for 75 dB. In addition, patients compared with normals had more nonspecific fluctuations, higher skin conductance levels, and a shorter response latency to the first stimulus. Stepwise discriminant analyses classified patients and normals better in the 100 dB than in the 75 dB condition, and showed that the various skin conductancy variables were largely redundant at the higher intensity.

Effects of stimulus repetition, duration, and rise time on startle blink and automatically elicited P300

Intense auditory stimuli of sudden onset evoke not only startle blinks but also an event-related potential component resembling classic P300, even when subjects have no assigned task. To more closely examine the relationship of this P300 to startle, event-related potentials and eyeblink were recorded from 16 young adults in three paradigms designed to produce wide variation in startle amplitude: an Habituation series of 30-ms, 105dBA white noise bursts, a Duration paradigm which presented 105dB noise bursts for 3, 10, 30, or 90 ms, and a Rise Time paradigm which varied the rise/fall times (3, 15, 30, and 45 ms) of 110dBA, 1000-Hz tone bursts. Subjects received two runs of each paradigm. Only on the final Duration and Rise Time runs were stimuli explicitly task relevant; on those runs subjects rated verbally, midway in each 8.4-s interstimulus interval, the disturbingness of the prior sound. Although even the briefest noise bursts evoked parietal P300 as well as startle blink, P300 did not behave like startle. P300 habituated more slowly than did blink amplitude, was more responsive to sustained noise than were blink, N110, and P190, and most importantly, did not show the sensitivity to stimulus rise time manifested by these measures. These findings suggest that the amplitude of automatically elicited P300 is not governed by the same mechanisms as startle amplitude, but behaves more like a defense response.

Motor activity and tonic heart rate in panic disorder

Motor activity and tonic heart rate were monitored in 62 drug-free panic disorder patients and 40 normal control subjects. Mean daily activity, mean waking heart rate controlled for activity, and mean sleeping heart rate were determined. Panic disorder patients without phobic avoidance showed higher activity than control subjects or patients with limited or extensive avoidance. Similarly, an "inverted U", relationship between trait anxiety and activity was observed. On the other hand, neither mean waking nor sleeping heart rate showed significant differences between patients and controls, suggesting that the differences previously reported in laboratory studies result from anticipatory anxiety.

Surreptitious drug use by patients in a panic disorder study

In a double-blind, placebo-controlled trial comparing alprazolam and imipramine for panic disorder, serum analysis revealed that a substantial proportion of the patients took explicitly prohibited anxiolytic medication. Excluding these patients changed the results.