The Caregivers of Stroke Patients: An Investigation of Factors Associated with Depression

Caregivers of the elderly and infirm are often under more stress and report lower life satisfaction than matched groups of noncaregivers. Forty caregivers of stroke patients (usually a spouse) were interviewed an average of 9 months poststroke to determine the factors associated with poorer caregiver adjustment. Four classes of variables were expected to be related to depression in caregivers: level of functioning of the patient, caregiver perceptions of increased work and burden due to the stroke, the quality of the patient-caregiver relationship, and caregivers' interpretations of their situation. Background characteristics were also measured. As predicted, variables in each class were significantly related to depression. Multiple regression analysis showed three significant independent predictors of caregiver depression. Caregivers are more depressed if the patient is more physically impaired, if caregivers report disharmony in the family, and if they have lesser perceptions of hope Ways to apply these findings to the development of interventions to ameliorate caregiver depression are discussed.     

Discrimination of mirror-image shapes by young children

Experiments were conducted to examine the difficulty six-year-old children have in discriminating visually between a shape and its lateral reversal, relative to the difficulty in discriminating between a shape and its inversion. Contrary to results with simultaneous presentation, under successive presentation there was no difference between the difficulty of discriminating lateral reversals and difficulty of discriminating inversions. This was also the case for successive presentation with trial-to-trial variation in position of shapes. Spatial adjacency of the shapes to a reference feature of the visual background accounted for the variations in difficulty between discrimination of lateral reversals and discrimination of inversions which obtained under simultaneous presentation.     

Behavioral parameters of drug action: signalled and response-independent reinforcement

Four pigeons were initially trained under a multiple variable-interval 1-min variable-interval 1-min schedule of food reinforcement. For two of the pigeons, a signal was then presented whenever the reinforcer was available in one component; this resulted in positive contrast. For the other two pigeons, the reinforcer was presented independently of responding on a variable-time schedule in one component; this resulted in negative induction. After 30 to 50 sessions, however, a similar degree of differential responding occurred under both multiple schedules, i.e., high rates in the variable-interval component and low rates in the other component. Reinforcement frequency remained about the same in each of the schedule components. The stable performances then served as baselines for studying drug effects. In the high-rate component of both multiple schedules, small doses of d-amphetamine increased responding, whereas larger doses decreased responding. In the low-rate component of both multiple schedules, there was no rate-increasing effect at any dose of d-amphetamine; such an effect was found, however, with phenobarbital at a dose that decreased responding in the high-rate component. The drug effects thus depended on the interaction of pharmacologic variables (specific drug and dose) with behavioral variables (schedule components).     

Monitoring animals’ movements using digitized video images

An animal’s movements can be monitored continuously using video digitization techniques. We outline the differences between video frame-grabbers and column-scan digitizers, and describe two applications using column-scanners: detecting episodes of spontaneous locomotion and tracking the position of a moving appendage. Strategies are discussed for increasing the speed of software and for compressing the information in the video images into an analog motion signal to be displayed and stored for later analysis. Finally, the advantages and limitations of frame-grabbers and column-scan digitizers are assessed.     

Autonomic and behavioral effects of dextroamphetamine and placebo in normal and hyperactive prepubertal boys

The hypothesis is tested that the response to dextroamphetamine in terms of activity, attention, impulsivity, and autonomic activity is similar in normal (N) and hyperactive (H) children. Fourteen N and 15 H boys had skin conductance (SC), heart rate (HR), and finger temperature (ST) recorded during rest, presentation of eight 75- dB tones, and a reaction time (RT) procedure on three occasions: off drug (Day 1) and after ingestion (double-blind) of placebo and of .5 mg/kg dextroamphetamine. Both N and H groups showed drug effects, compared to placebo, of reduced motor activity and impulsivity, improved attention (RT), increased HR and HR slowing during RT foreperiods, and decreased ST. Both groups also had decreases in SC responsivity but in different parts of the test. Placebo compared to Day 1 produced increased activity and autonomic arousal but no change in RT. Stimulant drugs thus have similar behavioral and autonomic effects in both N and H boys, but the beneficial effects on behavior do not depend critically on increases in arousal.