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Biomedical subjects

W T Roth

Publications and source records attributed to W T Roth.

At least 19 recordsLinked to original sources
PubMed1999

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.

Adult↗
PubMed1998

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.

Adult↗
PubMed1998

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.

Adult↗
PubMed1998

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.

Adult↗
PubMed1997

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.

Adult↗
PubMed1996

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.

Adult↗
PubMed1996

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.

Adult↗
PubMed1995

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.

Adult↗
PubMed1995

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.

Acoustic Stimulation↗
PubMed1995

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.

Adolescent↗
PubMed1994

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.

Adult↗
PubMed1994

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.

Adult↗
PubMed1992

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.

Adult↗
PubMed1992

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.

Adult↗
PubMed1992

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.

Humans↗