Examination of an antecedent communication intervention to reduce tangibly maintained challenging behavior: a controlled analog analysis.

We examined the influence of an antecedent communication intervention on challenging behavior for three students with developmental disorders. Students were taught to request tangible items that were identified as reinforcers for challenging behavior in a prior functional analysis. Individual participant multielement and reversal designs were used to compare the effects of the antecedent communication intervention versus a no antecedent communication intervention condition. Immediately following the antecedent manipulations students were exposed to the tangible condition of the functional analysis. Results indicate that the antecedent communication intervention reduced challenging behavior in the subsequent tangible test condition for all three students. The importance of examining antecedent interventions to treat challenging behavior from a function analytic perspective is discussed.

Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.

BACKGROUND: While chronic ß-Hydroxy ß-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC). METHODS: Sixteen non-resistance trained men (22 ± 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise. RESULTS: There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time x group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time x group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise. CONCLUSION: Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH.

Performance in auditory and visual emotional stroop tasks: a comparison of older and younger adults.

Research has shown age-related declines in the cognitive ability to inhibit irrelevant information. Thirty-six younger adults (mean age = 22 years) and 36 older adults (mean age = 74 years) performed 2 versions of an emotional Stroop task. In one, they made lexical decisions to emotion words spoken in 1 of several tones of voice. Latencies were longer for test words spoken in an incongruent tone of voice, but only for older adults. In another, words were displayed on a computer screen in a colored font, and participants quickly named the font color. Latencies were longer for test words high on arousal, but only for older adults. Results are discussed in terms of inhibitory cognitive processes, attention, and theories of emotional development.