Relaxation pretraining, pulse wave velocity and thermal biofeedback in the treatment of essential hypertension.

Twelve white male subjects with a physician's diagnosis of essential hypertension participated in the study over a 3- to 4-month period (23-38 sessions). Subjects were assigned to one of four sequences of training in which the order of presentation of pulse wave velocity (PWV) or thermal feedback, and presence or absence of relaxation pretraining were varied. The overall effectiveness of the treatment program was demonstrated by average blood pressure decreases of 8.8 mm Hg/4.1 mm Hg from initial session measures to follow-up one month after completion of the program. Systolic pressures were significantly lower at follow-up but not diastolic. In addition, 3 subjects had ceased taking any blood pressure medication by follow-up, and maintained normal pressure. The effectiveness of relaxation pretraining was demonstrated by the fact that relaxation pretrained subjects attained significantly greater blood pressure decreases from baseline to the last 3 sessions of training, and by the fact that relaxation pretraining appeared critical in the acquisition of PWV feedback training.

EEG biofeedback and relaxation training in the control of epileptic seizures.

Research utilizing sensorimotor rhythm (SMR) biofeedback with epileptics suggests that it is useful in decreasing seizures. Subjects were 6 young adults with a diagnosis of epilepsy of at least two years who had been unable to control their seizures with different regimens of anticonvulsant medications. Subjects ranged from severely mentally handicapped to above average functioning. Seizure type, frequency, and duration were recorded by subjects and caretakers. Measures of operant learning were percent time in SMR. The experiment utilized a single subject multiple baseline design which consisted of 6 phases: baseline one, relaxation training; baseline two, biofeedback training one; baseline three, biofeedback treatment two and follow-up. The results of this study are in agreement with other studies using SMR biofeedback. All subjects were able to significantly increase percent time in SMR. Five out of the 6 subjects demonstrated decreases in seizure frequency during the treatment phase. Two of the 6 subjects benefited from relaxation training. Four subjects demonstrated significant negative correlations between percent SMR and seizure rats. Consistent with other studies utilizing multiple baseline designs, a majority of the subjects did not follow the design of the study.

Free field localisation with a single sound transducer.

An auditory localisation task involving 360 degrees azimuth was performed by three subjects in a large anechoic chamber. A single sound source of a rotating form was employed. Responses were measured to the nearest 10 degrees of azimuth. Under a control condition of 'no helmet' localisation was within measurement errors for all degrees of azimuth. Under conditions of a DH-178 helmet in passive mode, the response field narrowed considerably, and with DH-178 active a further narrowing of the response field occurred. A DH-140 helmet in active mode showed the most degradation of response field. With the helmets in the active mode all sounds were heard as emanating from inside the head.

Auditory localization in a free field using discrimination procedures.

A rotating boom positioned a loudspeaker at ear height at a distance of 4 ft from the center of the head of S, who was seated in a darkened large anechoic chamber (684 ft); 750-msec bursts of pink noise, separated by 3.25 sec, at 54 db SPL, were presented. During the interstimulus interval the speaker was moved cw or ccw in the presence of a masking noise at 73 db SPL. Practiced young adults (2F, 1 M) judged azimuth "same" or "different"; minimum discriminable angle (MDA) was taken as P(c) = .70, corrected for false alarms (judgments "s" or "d" with no movement). Standard azimuths relative to S were at the 8 cardinal points. MDAs were best at 0 degree (c. 4.5 degrees) but were still relatively good (c. 8.5 degrees) at 180 degrees. In general, MDAs were poorer in the rear quadrants. One S excelled at MDA and exhibited the lowest false alarm rate. The effect of the masker, and random selection of standard and azimuth and of comparison stimuli at every trial, help explain the rather large MDAs compared with the minimum audible angles in the literature. The rather large determination at 90 degrees azimuth as determined by Mills (1958) was not found in these data.

Onset-offset effects of the human brainstem auditory-evoked response.

Brainstem auditory-evoked responses (BSAER's) were obtained from 4 normal-hearing young adults to a 2-kc/s tonal stimulus of 2-, 3-, 4-, 5-, 6-, 7- or 8-msec duration at 60 db sensation level. Latency of Jewett Wave V was recorded averaging 4096 sweeps; stimuli had a 1-msec rise-fall time, with a 65-msec interstimulus interval. A Wave V response to the onset transient was present for all durations. For stimulus durations of less than 5 msec no reliable offset response was noted. Latency measures indicated the onset response to be much less variable than the offset response. The onset response latency of Wave V remained stable over a stimulus duration range of 2-8 msec. The BSAER of a single S demonstrated the intrasubject variability of the offset response as a function of stimulus duration.

Reduction of blood pressure by indirect biofeedback.

Forty-five randomly assigned subjects served in either a relaxation control, an EMG plus thermal, or a thermal biofeedback group. All groups received the same relaxation manipulation. Experimental results demonstrated a significant drop in both diastolic and systolic blood pressure for the feedback treatment. Diastolic measures showed a somewhat greater decrease for the EMG plus thermal treatment condition. A learning effect was demonstrated both within and across the three experimental sessions. Given that the sample was normotensive, the 20% reduction in blood pressure was notable. The results support the idea that blood pressure biofeedback is not a necessary condition for reduction of arterial blood pressure.

Effects of EMG and thermal feedback training on tinnitus: a case study.

This case report describes a patient who exhibited the usual complaints of frustration, annoyance, and lack of sleep associated with severe tinnitus. After 2 months of weekly biofeedback sessions along with home training with a portable thermal biofeedback unit, the patient was relieved of the psychological symptoms associated with the tinnitus. A 1-year follow-up demonstrated that the patient remained complaint-free of psychological symptoms although the subjective loudness of the ringing was judged to be the same as at the onset of the tinnitus. The results indicate that biofeedback is a useful procedure in the treatment of severe tinnitus.

A short-term memory influence on the N1 response of cerebral cortex.

The N1 component of auditory evoked potentials varies in amplitude as a function of the direction of attention and has been treated as a physiological correlate of stimulus set. Results from a sequential pitch memory experiment, presented here, show that N1 also indexes the strengths of short-term associations, suggesting that the N1 mechanism(s) may be involved in a more general process of organizing and/or maintaining temporary sensorimotor memories.

An "inhibitory" influence on brainstem population responses.

Forward masking was used to obtain measurements of physiological masking and two-tone unmasking from short-latency evoked potentials and psychophysical responses in human subjects. The physiological results are in qualitative agreement with data on inhibitory phenomena in nonhuman auditory systems. The neural and behavioral data obtained thus far agree well.

Auditory temporal resolution: effects of sensation level.

Experienced Ss identified (2IFC) the signal complex that contained a gap. When the complexes were of the same frequency, gap detection remained constant over the durations employed (up to 300 msec). When duration of the signal was 10 msec no changes in gap threshold occurred over the range of frequency disparities between signals (up to 120 Hz at F0 = 1 kHz). However, as signal duration increased (beyond 10 msec) there was an increase in gap threshold with increased frequency disparity. The degradation in gap threshold was greater for longer-duration events. Gap threshold was shown to decrease as a function of increase in intensity of the signals.

Signal onset and task variables in auditory evoked potentials.

Two auditory evoked potential studies were run to determine the effects of stimulus rise times on amplitude of N1-P2 onset and offset potentials. Onset potentials were reduced with increased onset durations. No consistent relationship was found in N1-P2 offset potentials as a function of stimulus rise time. The effects of listening tasks and stimulus duration were also examined.