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Model Estimation and Evaluation
Published in Douglas D. Gunzler, Adam T. Perzynski, Adam C. Carle, Structural Equation Modeling for Health and Medicine, 2021
Douglas D. Gunzler, Adam T. Perzynski, Adam C. Carle
Ordered-categorical variables in research samples may show a floor effect or ceiling effect. A floor effect occurs when a high proportion of individuals endorse the minimum score on the observed variable. In contrast, a ceiling effect occurs when a high proportion of individuals endorse the maximum score on the observed variable. For an example, the frequency counts in the first category (endorsing the category for “not at all”) were high relative to the other categories in each of the nine items for the PHQ-9 in a sample of 644 hemodialysis patients, thus exhibiting a floor effect. As a consequence, the presence of floor and ceiling effects reduce variability in the reported data with most of the values at an extreme value. Robust WLS or ML with numerical integration can be used to analyze ordered-categorical data with a floor or ceiling effect.
Critical care, neurology and analgesia
Published in Evelyne Jacqz-Aigrain, Imti Choonara, Paediatric Clinical Pharmacology, 2021
Evelyne Jacqz-Aigrain, Imti Choonara
Codeine has lower affinity for μ-receptors than morphine and reduced effectiveness. An analgesic ceiling effect is apparent with increasing dose, only causing increased side effects. Analgesia may be mediated through morphine, but codeine receptor occupancy contributes to side effects [68]. There is little evidence for the broad belief that codeine causes less side effects, such as sedation and respiratory depression, compared with other opioids [66]. Combination paracetamol 1000 mg/codeine 60 mg in adults provides better analgesia than codeine 60 mg, illustrating the synergistic effect of analgesic combinations [69].
Management of chronic myofascial pain: finding common ground
Published in Kirsti Malterud, Steinar Hunskaar, Chronic Myofascial Pain, 2018
Kirsti Malterud, Steinar Hunskaar
Non-steroidal anti-inflammatory drugs can be helpful in pain states of mainly nociceptive origin and mild-to-moderate intensity. They can be combined with other medications, but are usually not effective in syndromes with symptoms of emotional distress. The best results will be achieved if the patient takes daily dosages without waiting for the pain to reach its maximum threshold. Some patients benefit from periodic use of these drugs, mainly in periods of high pain levels. The drugs have a ceiling effect, meaning that increasing the dosages beyond a certain threshold does not increase analgesia. Many patients do not continue using these drugs, mainly due to common adverse effects.
Neurocognitive effects of atypical antipsychotics in patients with first-episode schizophrenia
Published in Nordic Journal of Psychiatry, 2020
Yanyan Hou, Jiaheng Xie, Yanbo Yuan, Zhang Cheng, Xue Han, Lei Yang, Xin Yu, Chuan Shi
Dividing the 12 months study into two 6-month periods, two domains, visual learning and memory, and working memory and attention showed different treatment effects over the two periods. The significant improvement in visual learning and memory during the first half of the study was not sustained during the second half. Patients’ performance went back to baseline levels. For working memory and attention, treatment effect was sustained during second half but did not get significantly larger. The lack of longer-term improvement in these two domains might be in line with the overall unresponsiveness in vocabulary learning and memory, as these memory-related functions might be particularly difficult to treat. Structural and functional deficits in hippocampus had been consistently observed in patients with schizophrenia and the changes started during first episode [26,27]. Many studies have shown that hippocampal volume correlates with memory-related functions in psychotic patients [28,29]. If the medications can only lead to functional but not structural improvements, the limitation of therapeutic effects may be the result of ceiling effect from hippocampal deficits.
Pain assessment for chronic lower back pain: performance of the PAL-S and PAL-I patient-reported measures for symptoms and impacts
Published in Current Medical Research and Opinion, 2020
Donald M. Bushnell, Mona L. Martin, Mariёlle Eerdekens, Annette Christoph, Georg Kralidis, Hiltrud Liedgens
For items 2–14, the full range of response options (0–3) was used for 11 of the 13 items. For items 13, “worst aching,” and 14, “worst stiffness,” only responses 1–3 were used, and no subject answered “Not at all,” for these items. Mean scores ranged from 1.0 (most sensitive) to 2.6 (worst aching). Ceiling effects are defined as those responses at the top of the response scale where respondents have no pain at all (and thus cannot get any better). The highest ceiling effect was seen with item 4, “most sensitive (as if sunburned or raw to touch),” with 45 subjects (43.3%) answering “not sensitive at all.” Two other items, 3, “worst prickling,” (38.5%) and 10, “worst squeezing,” (34.6%) were above 33% (a third of the sample), the rest were under 30%. The highest floor effect (most severe response) was item 13, “worst aching,” with 68 subjects (65.4%) answering “very aching.” There were no missing data for the PAL-S. Only 1 pair of items was highly correlated: item 2 (rate your worst sharp [stabbing] back pain) was highly correlated with item 8 (rate your worst shooting back pain) (r = 0.67). Item-to-total correlations, for most items, showed acceptable associations between each item against the rest of the items as a total score (excluding that item). One item had a lower than expected association (<0.30): rate your worst aching (sore, nagging) back pain (0.257).
Effects of vortioxetine on functional capacity across different levels of functional impairment in patients with major depressive disorder: a University of California, San Diego Performance-based Skills Assessment (UPSA) analysis
Published in Current Medical Research and Opinion, 2020
William Jacobson, Wei Zhong, George G. Nomikos, Michael Cronquist Christensen, Christina Kurre Olsen, Philip D. Harvey
The results from this analysis showed improvement in UPSA composite scores for vortioxetine-treated patients with lower baseline UPSA composite scores, whereas a significant effect was not achieved in patients with higher baseline levels of functional capacity. Further studies will elucidate whether the latter finding reflects a diminished treatment effect or lack of sensitivity in the higher-functioning patients because of ceiling effects. Based on a previous study, a change from baseline in UPSA composite score of ≥7 points defined a CID threshold26. Here, we analyzed response rates across a broader range of thresholds to capture the variability within each and demonstrate the impact of treatment on functional capacity. We observed a greater proportion of patients treated with vortioxetine than placebo had improvement in UPSA composite score at each of the thresholds analyzed, demonstrating the robustness of this effect.