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PubMed1985

Penalty for impulse noise, derived from annoyance ratings for impulse and road-traffic sounds.

In the laboratory, four groups of 16 subjects rated the annoyance caused by three types of impulse sounds (regular and irregular gunfire noise and metal-construction noise) and by road-traffic sounds, all presented in background noise. The subjects were presented with the sounds for 5-min periods. The annoyance ratings were related to the A-weighted equivalent level (Leq) of the sounds. From these annoyance ratings a correction term or penalty was derived, which, added to the Leq of the impulse sounds, gives the level of equally annoying traffic noise. The correction was determined for conditions in which (1) only the annoyance caused by specific sources, or (2) the annoyance caused by the total sound (specific source plus background) had to be rated. In addition, the indoor Leq of the constantly present background noise was 35 or 55 dB(A) by and large, the results showed that for lower levels of the sounds an impulse-noise correction of at least 10 dB was required, whereas for higher levels the derived correction was about equal to the ISO/R 1996 penalty of 5 dB. This conclusion, based on the relation between Leq and annoyance ratings, is consistent with the correction based on Leq and the percentage of subjects who reported to be "very much annoyed." For equivalent levels of the impulse sounds at which 33% of the subjects claimed to be very much annoyed, the correction was 10 dB for the conditions in which the indoor Leq of the background noise was 35 dB(A), and 5 dB when this Leq was 55 dB(A).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Effects of impulse frequency, PTP, and temperature on responses elicited in large populations of motoneurons by impulses in single Ia-fibers.

Excitatory postsynaptic potentials (EPSPs) were evoked in large populations of motoneurons by impulses in single Ia- and group II fibers and recorded from L7 and S1 ventral roots by means of a sucrose-gap technique and spike-triggered averaging, as previously described (33, 34). Factors known to influence conduction at branch points in peripheral nerves or transmission in the Ia projection to motoneurons were studied to determine their effects on these postsynaptic population potentials (PSPPs). When impulse frequency was plotted against the amplitude of these PSPPs, a sequence of low-frequency depression, higher frequency facilitation, and still higher frequency depression was regularly observed. Similar plots of PSPP amplitude versus impulse frequency in a small sample of group II spindle fibers did not reveal any low-frequency depression. Higher frequency facilitation and depression followed the same pattern as that produced by Ia-fibers. Early potentiation of the PSPPs was produced by applying 20 stimulating pulses at 500/s to branches of the medial gastrocnemius nerves containing single Ia-fibers. Single, posttetanic PSPPs were recorded at fixed intervals following each tetanus and averaged. A brief, initial depression followed by a rapidly declining potentiation of PSPPs was regularly observed. When the core temperature was reduced from 41 to 35 degrees C, there was an approximately linear increase in the amplitude of PSPPs. At each temperature a combination of cooling and posttetanic potentiation (PTP) elicited larger PSPPs than cooling alone. The effects of impulse frequency, PTP, and temperature on PSPPs may all be interpreted in terms of their known effects on action potentials or on conduction at branch points in peripheral nerves. Similar effects on transmission or transmission failure in the terminal arborizations of Ia-fibers would account for the influence of these factors on PSPPs. Alternatively, these same three factors might cause similar effects on PSPPs through influences they might exert on the transmitter release mechanism.

Animals↗
PubMed1980

Impulsivity and persistence in adult inpatient "impulse" offenders.

Related cognitive tempo, self-report measures, and ratings of behavior to task persistence and persistence in treatment in adult inpatient/drug/alcohol/sex ("impulse") offenders (N = 43). Matching Familiar Figures test latencies and self-control scale scores were related to task persistance, but only the behavior ratings produced significant relationships with persistence in treatment. Although cognitively impulsive Ss were less task persistent than reflectives, impulsive and reflective Ss did not differ on self-reported locus of control and self-control, on the behavioral ratings, or on persistence in treatment. Behavioral ratings were most efficient for making predictions about persistence in treatment.

Adult↗
PubMed2003

Understanding the role of impulsivity and externalizing psychopathology in alcohol abuse: application of the UPPS impulsive behavior scale.

The present study explores the relation among 4 personality traits associated with impulsive behavior and alcohol abuse. Personality traits were measured using the 4 subscales of the UPPS Impulsive Behavior Scale (UPPS; S. P. Whiteside & D. R. Lynam, 2001). The UPPS and measures of psychopathology were administered to clinical samples of alcohol abusers high in antisocial personality traits (AAPD), alcohol abusers low in antisocial personality traits (AA), and a control group (total N = 60). Separate analyses of variance indicated that AAPDs had significant elevations on all 4 UPPS scales, whereas the AAs and controls differed only on the Urgency subscale. However, when controlling for psychopathology, group differences on the UPPS scales disappeared. The results suggest that personality traits related to impulsive behavior are not directly related to alcohol abuse but rather are associated with the elevated levels of psychopathology found in a subtype of alcohol abusers.

Adult↗
PubMed1997

Mechanisms for absence of inverse relationship between coupling intervals of premature impulses initiating reentrant ventricular tachycardia and intervals between premature and first tachycardia impulses.

BACKGROUND: During initiation of tachycardias by programmed stimulation (PES), an inverse relationship between the coupling interval of the premature impulse (V1V2) and the interval between the premature impulse and the first impulse of tachycardia (V2T1) has been proposed to be a specific indicator of reentry. However, an inverse relationship has not always been observed during initiation of clinical reentrant ventricular tachycardias (VTs). METHODS AND RESULTS: Reentrant VT was initiated by PES in twelve 4-day-old infarcted dog hearts. The relationship between V1V2 and V2T1 was always direct. Mapping of the epicardial border zone (EBZ) indicated that initiation of VT was secondary to functional orthodromic block of V2, propagation of V2 around the line of block, and antidromic propagation through the original location of the block. In 7 dogs, the line of orthodromic block and the pathway of orthodromic propagation were similar for different V1V2 coupling intervals. Orthodromic conduction time around the line to its distal side was longer at shorter V1V2 intervals, but a shorter antidromic delay in the area of unidirectional block for shorter V1V2 intervals, possibly reflecting small changes in the conduction pathway involving deeper layers of the EBZ, resulted in shorter V2T1 intervals. In the other 5 dogs, the orthodromic conduction pathway of V2 around the line of block changed markedly, with a shorter pathway for shorter V1V2 intervals resulting in shorter V2T1 intervals. CONCLUSIONS: An inverse relationship between V1V2 and V2T1 is not a specific indicator of functional reentry.

Animals↗
PubMed2000

The interaction between impulsivity and neighborhood context on offending: the effects of impulsivity are stronger in poorer neighborhoods.

This research blends 2 traditions of theorizing on the causes of crime, one focused on the role of individual differences and the other focused on structural and contextual variables. Two related studies examined the relations among impulsivity, neighborhood context, and juvenile offending. The first, cross-sectional study uses a large sample of 13-year-old inner-city boys, whereas the second, longitudinal study offers a conceptual replication using 17-year-old inner-city boys who are a subset of the original sample. Across both studies, results indicate that the effects of impulsivity on juvenile offending are stronger in poorer neighborhoods. Furthermore, nonimpulsive boys in poor neighborhoods were at no greater risk for delinquency than nonimpulsive boys in better-off neighborhoods.

Antisocial Personality Disorder↗
PubMed1994

When is "impulsiveness" not impulsive? The case of hyperactive children's cognitive style.

On two computerized versions of the Matching Familiar Figures Test (MFFT; Kagan, Child Development, 36, 609-628, 1965) pervasively hyperactive and matched control children had to identify a target from among five similar foils. One version had a temporal structure similar to the manual MFFT and trial length was determined by response speed. Hyperactive children behaved in an "impulsive" manner; they responded more quickly and made more mistakes than controls. Despite this they completed each trial more quickly than controls by identifying the target. On the second version, the length of each trial was fixed at 45 seconds. Although both groups were equally "reflective", hyperactive children still made more mistakes. Implications of these results for research in impulse control in general and hyperactivity in particular are discussed.

Attention Deficit Disorder with Hyperactivity↗
PubMed2004

Self injurious behaviour in Tourette syndrome: correlates with impulsivity and impulse control.

BACKGROUND: Self injurious behaviour (SIB), the deliberate, repetitive infliction of self harm, is present in a wide variety of neuropsychiatric disorders, including Tourette syndrome (TS). Although SIB occurs in up to 60% of individuals with TS, and can cause significant clinical impairment and distress, little is known about its aetiology. OBJECTIVE: This study examined the relationship between SIB and other behavioural features that commonly co-occur with TS in nearly 300 subjects with TS participating in three genetic studies. SIB, obsessions, compulsions, tic severity, attention deficit hyperactivity disorder related impulsivity, risk taking behaviours, and rages were systematically assessed in all subjects. METHODS: Using logistic regression, a best fit model was determined for both mild to moderate SIB and severe SIB. RESULTS: Mild/moderate SIB in TS was correlated with the presence of obsessive and compulsive symptoms such as the presence of aggressive obsessions or violent or aggressive compulsions, and with the presence of obsessive-compulsive disorder and overall number of obsessions. Severe SIB in TS was correlated with variables related to affect or impulse dysregulation; in particular, with the presence of episodic rages and risk taking behaviours. Both mild/moderate and severe SIB were also correlated with tic severity. CONCLUSIONS: This study suggests that mild/moderate and severe SIB in TS may represent different phenomena, which has implications for clinical management of these symptoms.

Adolescent↗
PubMed1977

Responses of crayfish muscle preparations to nerve stimulation with various patterns of impulse sequence. Effects of intermittent, intercalated and adaptational types of impulse sequence.

The present study was carried out with an attempt to see what effects would be produced by various patterns of impulse trains other than pulses of a definite frequency in nerve-muscle systems of the crayfish. Single axons of nerves of the opener, the slow closer and the fast closer of the crayfish claw were stimulated and the tension development of muscles were recorded. The impulse trains tested are as follows: (i) intermittent stimulation; e.g., paired (doublet) and triplet stimuli, (ii) the intercalated stimulation during stimulation by constant-frequency pulses and (iii) the adaptational type of stimulation, i.e. a train of pulses of which interval gradually increases as seen in the process of the adaptation in the sensory nerve. Results obtained are as follows. Intermittent doublet stimuli produced a greater tension than the monotonous stimulation of the same average frequency. Repetitive triplet or quadruplet stimuli caused further increments in the tension development. Intercalation of a stimulus during usual monotonous stimulation induced a catch-like effect on the tension. Intercalated triplet stimuli provoked a stronger catch action. With the adaptational type of stimulation, an initial rapid tension development occurred with a least latency and this was followed by a maintained tension. There are certain temporal configurations of stimuli which produced a greater tension or a more physiologically meaningful time course of tension development. This suggests the significance of nervous coding.

Animals↗
PubMed1991

[Postmortem behavior of impulse transmission latency--impulse transmission strength curves].

Strength-duration curves (i/t-curve) are describing the dependence of the threshold intensity of rectangular impulses from their duration; in clinical neurophysiology they help to clarify whether a muscle is denervated or not. In the post-mortem interval from 2 to 9 hpm the pm. changes of strength-duration-curves were investigated on 17 bodies; muscular contraction was objectified using a sensitive force transducer pricked into the muscle. The muscle was stimulated with constant-current rectangular impulses of 5 to 1000 msec. duration and current intensities which produce a force of muscular contraction of 2.5 mN each half an hour. The strength-duration-curves of human bodies taken at the earliest possible time p. m. (2 hpm) show already the pattern of partially or total denervation (steep rise of threshold values for duration of stimuli shorter than 100 msec). As for the rheobase there is a strong linear relationship between ln of the threshold and time since death for duration of stimuli below 1000 msec. Extrapolation of the time since death on the basis of threshold values of different duration of stimulations of an i/t-curve reveals only small rise of precision of death time estimation compared to extrapolation of the time since death just with the rheobase.

Adolescent↗