Measuring impaired performance with the NRC "stressalyser"

Fentanyl and Driving Impairment

The incidence of fentanyl in forensic toxicology analyses in the USA has dramatically increased over the past several years. The increase in death cases has been well studied; however, little has been reported on the impact to drug impaired driving. Fentanyl driving while under the influence of drugs (DUID) case data from 2014 to 2019 is presented. The data were obtained from three toxicology laboratories in the Northeast, Southeast, and Midwest regions of the USA. Fentanyl whole blood concentrations ranged from 0.1 to 157 ng/mL in living drivers with a 466% to 524% increase in fentanyl-positive DUID cases from 2014 to 2019, depending on the US region. The vast majority of fentanyl cases involved poly-drug use. Twenty case histories are presented where fentanyl was the only drug identified. The mean (standard deviation) fentanyl concentration for these cases was 5.2 ± 3.8 ng/mL with a median of 3.7 ng/mL, and the concentrations ranged from 2.0 to 16 ng/mL. Naloxone administration was documented in exactly half of these cases similar to another study involving carfentanil-impaired driving. The case histories also demonstrate that some recreational opioid users may display limited signs of impairment either due to tolerance or naloxone administration. The top three observations in common among the cases were the driver was found unresponsive behind the wheel, the vehicle left the travel lane or roadway, and the driver was involved in a crash. The increase in fentanyl use not only poses a risk for overdose and death, but is also a significant concern for traffic safety. This study supports the movement of fentanyl from a Tier II drug to Tier I due to its significant potential for impairment and increase in prevalence in impaired driving cases.

Components of Proactive Transfer in Motor Performance

While many variables influence the transfer of learning, it has been suggested that preestablished strategies represent a key factor in intertask transfer. 48 subjects performed trials on a tracking task for which the stimulus conditions were held constant but the response requirements were reversed. Three experimental groups had differing amounts of practice on the original task, and a no-practice group served as a control. The resulting transfer effects were not related to the amount of previous practice, but only to the distinction between practice and no-practice groups. Although there was evidence of both proactive facilitation and interference, the predominant factor affecting performance appeared to be the preestablished response strategies of the experimental groups.

Exposure to estrogen mimicking the level of late pregnancy suppresses estrus subsequently induced by estrogen at the level of the follicular phase in ovariectomized shiba goats

A high-estrogen environment during late pregnancy is suspected to cause postpartum silent ovulation, and progesterone (P₄) is suggested to recover estrus. However, few attempts have been undertaken to elucidate the influence of these steroids on estrus by analyzing hormonal profiles. We investigated estrus and luteinizing hormone (LH) surges in ovariectomized goats (n=6) assigned to three treatments in a cross-over design. In groups 1 and 2, 200 µg/kg body weight/day estradiol benzoate (Dose-200 E₂B) was administered for 14 days concurrent with P₄ for 11 days, while in the control, saline solution and P₄ were administered likewise. Ten days after the final administration of Dose-200 E₂B, group 2 was treated with P₄ for 8 days, and all groups were treated with 2 µg/kg body weight E₂B (Dose-2 E₂B) 20 days after the final administration of Dose-200 E₂B (or saline solution). The proportion of cases expressing estrus after the administration of Dose-2 E₂B was smaller (P<0.01) in group 1 than in the control (1/6, 3/6 and 6/6; groups 1 and 2 and the control, respectively). The proportions of cases generating LH surges did not differ (P>0.1) among the groups (5/6, 5/6 and 6/6; groups 1 and 2 and the control, respectively), but the peak concentrations in groups 1 and 2 (26.2 ± 14.7 and 11.3 ± 6.7 ng/ml) were lower (P<0.01) than those in the control (67.8 ± 19.4 ng/ml). These results demonstrated that elevation of plasma estrogen mimicking late pregnancy inhibits the subsequent estrus induced by estrogen simulating the follicular phase.

Complex Motor Performance and Parkinson's Disease

Une étude a été menée sur la performance de sept patients atteints de la maladie de Parkinson qui avaient à effectuer une tache de repérage de mouvements discontinue et qui, dans un premier temps, étaient sous medication (symptômes atténués) et, dans un deuxième temps, sans médication (symptômes non atténués). Les résultats obtenus ont été comparés avec ceux provenant de sept personnes d'âge et de sexe similaires et non atteintes de la maladie de Parkinson. Toutes les personnes ont donné 2 000 réponses au cours de la tâche, ce qui a permis d'obtenir des variations sur la probabilité directionnelle et la distance de déplacement. Dans l'ensemble, les résultats indiquent que lorsque les malades parkinsonniens sous médication obtenaient suffisamment de temps pour pratiquer et apprendre une nouvelle tâche, ils se comportaient de la même façon que les personnes témoins d'âge semblable. Cependant, on a noté deux situations ou les réponses des personnes atteintes de la maladie de Parkinson étaient visiblement plus lentes: (a) dans leur habileté à prendre des décisions lorsque la direction du mouvement était moins prévisible, et, (b) lorsqu'ils devaient rajuster leurs réponses motrices après un faux mouvement subit.

Responses of gonadotropin secretion to short-term dietary supplementation in ovariectomized goats with different body weights

The responses of luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion to acute dietary supplementation were studied in goats with different body weights. Ovariectomized Shiba goats (n=11) were used and were maintained with a feed of 100% of their energy requirement. They were implanted subcutaneously with an oestradiol capsule and were divided into light (LBW; <or=24kg, n=6, mean+/-S.D., 21.8+/-2.7kg) and heavy body weight (HBW; >24kg, n=5, mean+/-S.D., 32.0+/-6.3kg) groups on the basis of their body weights at 8 days before the start of treatment. At the start of treatment (Day 1), the level of a feed changed to 250% of their energy requirement and this level was maintained for 7 days in both groups. Blood samples were collected daily from Day -7 to Day 7 for the analysis of FSH, glucose, and insulin profiles in plasma. Frequent blood samples were also collected at 10min intervals for 6h on Day 0, Day 3, and Day 7 for analysis of LH pulses. LH pulse frequency increased significantly on Day 3 as compared with that on Day 0 in both the HBW (7.4+/-0.5pulses/6h vs. 6.2+/-0.8pulses/6h, p<0.05) and LBW (6.5+/-0.8pulses/6h vs. 5.5+/-0.5pulses/6h, p<0.05) groups, whereas it decreased on Day 7 (HBW, 6.4+/-0.9pulses/6h; LBW, 6.3+/-1.6pulses/6h, p>0.05 vs. Day 0). Plasma glucose and insulin concentrations increased temporarily from Day 2 to Day 4 and then decreased to the level before the start of dietary supplementation in both groups. There was no significant difference in the LH pulse frequency or daily concentrations of FSH, glucose, or insulin between the HBW and LBW groups throughout the experimental period. The present study indicated that acute dietary supplementation stimulates pulsatile LH secretion in parallel with a rise of blood glucose and insulin levels. However, the influence of body weight on these responses between light and heavy animals was not observed.

Aspects of Psychomotor Performance in the Recovery from Right Hemisphere Lesions

The ability to learn and perform a psychomotor task (pursuit tracking task) of ten subjects who had sustained right hemisphere lesions (RHL) was compared to ten healthy individuals matched for age and gender. The task required subjects to react and move quickly, varying both the distance to be moved and the choice of movement direction. All subjects completed 1200 responses across two testing sessions. Results indicated that while the RHL group was able to ‘learn’ the task as well as the Control group, they were slower at correcting unanticipated movement errors. In addition, the RHL group did not respond to changes in the probable direction of the next movement in the same manner as the Control group and, in fact, appeared unaware of changes in the probability of movement direction.

Impairment and recovery under repeated doses of alcohol: effects of response-outcomes

This research examined the behavioral effect of alcohol during rising and declining blood alcohol concentrations (BACs) when the dose was repeated three times (mean peak BAC = 78 mg/100 ml). A total of 36 male social drinkers learned a complex psychomotor task and subsequently performed it at intervals after alcohol was received. Subjects performed under one of two conditions: an experimental (E) treatment associated drug-compensatory (nonimpaired) task performance with a positively reinforcing outcome or a control (C) treatment associated no environmental consequence with performance. E treatment diminished impairment at all positions on the BAC curve and carried over to result in progressively less impairment when the dose was repeated. In contrast, C treatment tended to increase impairment around the BAC curve with repeated doses. The rate of recovery during declining BACs remained stable across sessions and was not altered by the treatments. The results imply that impairment under a dose of alcohol is governed by two processes: response-outcome associations that determine the amount of impairment displayed under a dose and some adaptive process that determines the rate of recovery with time during exposure to a dose.

Response outcomes affect the retention of behavioral tolerance to alcohol: information and incentive

Twenty-four male undergraduates acquired tolerance during three sessions where they received moderate doses of alcohol (0.62 g/kg) and repeatedly performed a motor skill task with immediate knowledge of results (KR) on each trial. Subjects were assigned to one of four groups (n = 6) before a retention test session where two groups received alcohol and two expected alcohol but received a placebo. The effect on tolerance retention of withholding KR was tested in alcohol group A. The effect of an incentive in the absence of KR was examined in the other alcohol group (AM) that was offered a delayed monetary reward for nonimpaired performance. Both alcohol groups failed to retain tolerance and their impairment did not differ. The effect of substituting the incentive for KR on a drug-compensatory response to placebo was examined in group PM by comparing its performance to group PC where KR was continued. A compensatory response (i.e., performance superior to drug-free baseline) was displayed by the PC group but not by group PM. Thus, despite a monetary incentive to perform well, tolerance to alcohol and a compensatory response to placebo were both disrupted by withholding KR. The results were interpreted in terms of the information about performance conveyed by KR.

Knowledge and motor performance

Traditionally, motor skill acquisition has implied that the performance of a given individual on a particular skill is dependent on the amount of prior practice of that skill. However, concepts such as schema theory, or kinetic formulae, or the strategic allocation of resources imply that, even when practising specific skills, performers gain knowledge about their own motor performance which can be used or applied to related or novel situations. An attempt was made to relate the performance of a complex psychomotor task to differing levels of motor skill expertise or knowledge (athlete and nonathlete). 20 subjects performed (1600 responses) on a novel pursuit or tracking task. Analysis indicated that the athletes performed significantly better. Their main advantage appeared to be more in their ability to control and produce fast, accurate movements than in their decision-making. Accepting Henry and Rogers' 1960 proposition that there is no such thing as a general motor ability or coordination factor does not imply that the only alternative is for all motor skills to be specific. It is argued that the differences in the present study arose from the athletes' greater knowledge (schema, kinetic formulae) related to their understanding of their own motor capabilities.

Independent Living and Psychomotor Performance

While the majority of seniors live outside of institutions, many live in seniors apartment buildings rather than in single family dwellings. MacPherson (1983) suggested that not maintaining an independent living style may have some negative consequences for seniors. The question asked was whether differences in lifestyle arising from the nature of the residence were associated with measures of psychomotor performance. Some 36 seniors, average age approximately 68 yrs., all in good health, completed 800 responses on a discrete pursuit tracking task which emphasized response speed and accuracy. Significant differences in performance were noted for both RT and speed of movement. Overall, seniors living independently, either in urban or rural areas, responded faster than seniors living in seniors apartment buildings. The data do not imply a causal relationship, however, they do suggest that psychomotor variables are relevant factors to consider in regard to differing living styles.

Response expectancies affect the acquisition and display of behavioral tolerance to alcohol

Two experiments demonstrated that a learned expectation of a favourable consequence for drug-compensatory performance enhanced behavioral tolerance to alcohol, and when the expectancy was trained, the subsequent display of tolerance depended upon its consequence. Both experiments involved each of four groups of six male social drinkers each, who drank 0.62 g/kg alcohol on four sessions, and a placebo on a fifth session. Experiment 1 provided two groups with the opportunity to learn the response expectancy by performing a motor task under alcohol with either an informative consequence (IO) or information plus money contingent upon drug-compensatory performance (MI). Two control groups performed with either no outcome (N), or with money for compensatory performance but no information about earnings until the experiment concluded (MO). The effects of learning history were evident on sessions 4 and 5 when the same consequence was contingent upon the performance of all groups. Compared to controls, the groups that had received response expectancy training (MI and IO) displayed significantly more alcohol tolerance and greater compensatory facilitation of performance under placebo. In Experiment 2, all groups received the same response expectancy training, and the effect of the consequence of compensatory performance was demonstrated during subsequent test sessions 4 and 5. An informative consequence (MI or IO) enhanced tolerance and the compensatory response to placebo, whereas performance with no response contingent information (N or MO), revealed little tolerance or compensatory response to placebo. Theoretical and practical implications of the findings were discussed.

Aging and the Response to Changes in Task Difficulty

Un exercice de repérage de signaux discontinus a été employé pour évaluer le processus de planification du mouvement (relié aux paramètres de direction et d'amplitude) comme source du ralentissement de l'initiation et de la production du mouvement chez les personnes âgées. Les personnes âgées ont démontré des temps de réaction et de mouvement plus lents, cette lenteur variant en fonction de la quantité d'informations traitées pour accomplir le mouvement. Cependant, les personnes âgées ont semblé aussi capables que des individus plus jeunes de corriger des erreurs imprévues de mouvement. Les données suggèrent que, bien que le processus de sélection du mouvement puisse constituer un facteur qui contribue au ralentissement chez les personnes âgées, l'identification de paramètres spécifiques du mouvement peut s'avérer plus importante dans l'accomplissement de certains mouvements que les quelques déficits généralisés associés au vieillissement.

Cognitions and alcohol-influenced performance: the impact of reinforcement contingencies

The effects of different reinforcement conditions on self-reported cognitions and task performance under the influence of alcohol were examined. Four groups of male university students attended a series of four drinking sessions. During the sessions, the groups performed a visual tracking task under different reinforcement conditions which influence the speed of acquisition of behavioural tolerance to the impairing effects of alcohol. At the end of each session, subjects completed a questionnaire intended to elicit any thoughts, feelings, ideas or images they experienced during the session. Their responses were scored in categories related to alcohol effects, task performance and motivation. The groups differed significantly on numbers of self-reported cognitions related to general alcohol effects and to alcohol effects on task performance; these differences corresponded to differences in the speed of tolerance development. In the group that acquired tolerance most rapidly, several aspects of task performance were significantly correlated with cognitions. These data provide support for the suggestion that cognitive activity may be an important factor in individuals' responses to alcohol and other drugs.

Reinforcement reduces behavioural impairment under an acute dose of alcohol

Two experiments employed a total of 25 male social drinkers who learned a complex psychomotor task (Tracometer) and subsequently performed it 20 times under alcohol (0.60 g absolute alcohol/kg) while blood alcohol concentrations (BAC) rose and fell. In each experiment, one group received reinforcement for drug-compensatory performance (RP) and one received no reinforcement (P). The BACs associated with the onset and offset of behavioral impairment under the dose were measured, and these thresholds were significantly higher in RP than P groups; reinforcement delayed the onset and also hastened the offset of drug effects. The accelerated recovery from impairment was considered to imply that reinforcement may facilitate the adaptive process involved in acute tolerance. Since this same reinforcement treatment accelerates the development of tolerance to repeated doses of alcohol, the results of the present research suggest that the behavioural effect of acute and chronic doses may both be similarly influenced by environmental learning factors.

The transfer of alcohol tolerance, and its relation to reinforcement

Four groups of five male social drinkers were trained on two different psychomotor tasks, a Pursuit Rotor (PR) and a Tracometer (T). They subsequently attended five drinking sessions where the same dose, 0.66 g absolute alcohol (ab alc)/kg, was administered. During these sessions, groups E and R received 'tolerance training' on the PR task by performing it under drug and receiving 25 cents reinforcement each time their score under alcohol was comparable to their drug-free level of achievement. The other two groups served as controls; group P performed the PR under alcohol but without reinforcement, and group A performed the PR with reinforcement but before alcohol was administered. The reduction of the drug-induced impairment of PR performance from Session 1-5 confirmed that groups E and R displayed significantly more tolerance than the controls. The effect of reinforcement on tolerance transfer to the T task was tested on Session 5. Groups E, P and A received reinforcement for T performance, and group R received no reinforcement. Since the E group displayed significantly more transfer of tolerance than the remaining three groups, the evidence confirmed the prediction that alcohol tolerance acquired via reinforced practice under drug transfers to a new task most readily when this reinforcement is also present.

The development of alcohol tolerance: acute recovery as a predictor

Two experiments examined individual differences in the rate of alcohol tolerance development as a function of acute recovery. Male social drinkers (n = 18) were trained on a complex psychomotor task and subsequently returned for four drinking sessions in which they received the same dose (0.84 ml absolute alcohol/kg) and performed the task at intervals while blood alcohol concentrations (BAC) rose and fell (peak BAC = 77.2 mg/dl). A subject's acute recovery from the impairing effect of alcohol during session 1 was measured by the difference in his performance at the same BAC on the rising and the falling limb of the curve. Rate-of-tolerance development was measured by the rate of change in the subject's average impairment under the alcohol during sessions 1-4. Acute recovery scores in both experiments significantly predicted the rate at which tolerance developed, accounting for 64% of the variance in these scores (P less than 0.0001). Subjects who displayed more acute recovery developed tolerance more quickly. The evidence was considered to imply that the same process may give rise to both acute recovery and tolerance.

Alcohol tolerance in social drinkers: operant and classical conditioning effects

Four groups of males (n = 6 each) were trained on a complex psychomotor task prior to attending five drinking sessions. They performed the task under the same dose (0.84 ml absolute alcohol/kg) on sessions 1-4. On session 5 they received a placebo. During these sessions, the first group (CR) received information and a monetary reward that was contingent on the display of nonimpaired performance under alcohol. The second group (IO) only received information about performance. The third group (NCR) received noncontingent information and reward, administered on a predetermined schedule. The fourth group (NR) received no information or reward for performance. These manipulations were predicted to influence the order of groups with respect to the rate at which tolerance developed over sessions 1-4. The findings confirmed this hypothesis, showing the rate of CR greater than IO greater than NCR greater than NR. The placebo session tested for the classically conditioned compensatory response unattenuated by alcohol. The strength of the response, observed as facilitated performance, was predicted and found to relate to the rate at which tolerance had developed (i.e., CR greater than IO greater than NCR greater than NR). This evidence for operant and classical conditioning effects in alcohol tolerance was considered to suggest that a consideration of their joint effects may be required to understand the contribution of learning to drug tolerance.