Abstract 14: Effects of Lesion Laterality on Post-Stroke Motor Performance: An ENIGMA Stroke Recovery Analysis

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Sook-Lei Liew ◽  
Neda Jahanshad ◽  
Lisa Aziz-Zadeh ◽  
Niels Birbaumer ◽  
Michael Borich ◽  
...  
Keyword(s):  
Motor Performance ◽  
Statistical Significance ◽  
Motor Recovery ◽  
Small Sample ◽  
Stroke Recovery ◽  
Intracranial Volume ◽  
Brain Volumes ◽  
Post Stroke ◽  
Small Sample Sizes ◽  
Cortical Regions

The laterality of the lesioned hemisphere is often overlooked in stroke recovery research due to small sample sizes. Here, we used a well-powered dataset from ENIGMA Stroke Recovery (a consortium that harmonizes post-stroke MRIs and behavioral data worldwide; http://enigma.usc.edu) to analyze the effects of left (LHL) versus right (RHL) hemisphere lesions on motor performance. Given the different functional roles of each hemisphere, we hypothesized that the LHL group should show better motor performance, and, consequently, different brain-behavior relationships, compared to the RHL group. Data from over 2000 stroke patients across 20 sites worldwide has been committed. To date, structural T1-weighted MRIs from n=343 (10 sites) have been analyzed (LHL n=174; RHL n=169). ENIGMA protocols extracted volumes of subcortical regions of interest and provided quality control. Regression analyses examined brain volumes as predictors of motor outcomes. Motor scores were combined across scales/sites, with each score expressed as a percentage of the maximum score. Covariates (e.g., age, sex, intracranial volume) and manually marked lesion effects were also modeled. Statistical significance was assessed nonparametrically by permutation. As anticipated, the LHL group had better motor performance compared to the RHL group (t(1,341)=3.07, p=0.0023). In addition, while the combined LHL+RHL analyses showed significant associations between motor scores and volumes of the basal ganglia/lateral ventricles, separate group analyses showed strong associations for the LHL group, but only one association for the RHL group (Table 1). This may suggest that motor recovery following RH lesions is more heterogeneous or relies more on cortical regions/networks that were not assessed here. While further research is needed, these results suggest that laterality of the lesioned hemisphere affects neural patterns related to motor recovery and should be carefully examined.

scholarly journals Bringing Proportional Recovery into Proportion: Bayesian Hierarchical Modelling of Post-Stroke Motor Performance

2019 ◽  
Author(s):  
Anna K. Bonkhoff ◽  
Thomas Hope ◽  
Danilo Bzdok ◽  
Adrian G. Guggisberg ◽  
Rachel L. Hawe ◽  
...  
Keyword(s):  
Motor Performance ◽  
Model Comparison ◽  
Synthetic Data ◽  
Motor Recovery ◽  
Stroke Recovery ◽  
Future Research ◽  
Single Subject ◽  
Bayesian Hierarchical ◽  
Post Stroke ◽  
Function Recovery

AbstractAccurate predictions of motor performance after stroke are of cardinal importance for the patient, clinician, and health care system. More than ten years ago, the proportional recovery rule was introduced by promising just that: high-fidelity predictions of recovery following stroke based only on the initially lost motor performance, at least for a specific fraction of patients. However, emerging evidence suggests that this recovery rule is subject to various confounds and may apply less universally than assumed by many.We systematically revisited stroke outcome predictions by casting the data in a less confounded form and employing more integrative and flexible hierarchical Bayesian models. We jointly analyzed n=385 post-stroke trajectories from six separate studies – the currently largest overall dataset of upper limb motor recovery. We addressed confounding ceiling effects by introducing a subset approach and ensured correct model estimation through synthetic data simulations. Finally, we used model comparisons to assess the underlying nature of recovery within our empirical recovery data.The first model comparison, relying on the conventional fraction of patients called fitters, pointed to a combination of constant and proportional to lost function recovery. Proportional to lost here describes the original notion of proportionality, indicating greater recovery in case of a more pronounced initial deficit. This combination explained only 32% of the variance in recovery, which is in stark contrast to previous reports of >80%. When instead analyzing the complete spectrum of subjects, model comparison selected a composite of constant and proportional to spared function recovery, implying a more significant improvement in case of more preserved function. Explained variance was at 53%.Therefore, our data suggest that motor recovery post-stroke may exhibit some characteristics of proportionality. However, the levels of explanatory value were substantially reduced compared to what has previously been reported. This finding motivates future research moving beyond solely behavior scores to explain stroke recovery and establish robust single-subject predictions.

Characterization of microsatellite instability (dMMR/MSI-H) and mutational landscape in a large contemporary cohort of upper tract urothelial cancer (UTUC) patients.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 465-465
Author(s):  
Arpit Rao ◽  
Julie Elaine McGrath ◽  
Joanne Xiu ◽  
Andre Luiz De Souza ◽  
Shuchi Gulati ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Chromatin Remodeling ◽  
Statistical Significance ◽  
Small Sample ◽  
Biological Pathways ◽  
High Rate ◽  
Chi Square ◽  
Mutational Landscape ◽  
Comparison Results ◽  
Small Sample Sizes

465 Background: UTUC is a rare genitourinary malignancy and a number of studies, limited by small sample sizes, have attempted to characterize its mutational landscape. Because immunotherapy is commonly used for this disease type, we evaluated the prevalence of microsatellite instability and characterized the mutational landscapes of UTUC in a large contemporary patient cohort. Methods: UTUC tumor samples were analyzed using next generation sequencing (NGS) (NextSeq, 592 gene panel) or whole exome sequencing (WES) (NovaSeq) (Caris Life Sciences, Phoenix, AZ). Mismatch repair status (deficient [dMMR] or proficient [pMMR]) and microsatellite instability status (MSI-high or stable [MSS]) were detected by immunohistochemistry (IHC), fragment analysis, and NGS. Tumor mutational burden (TMB) was measured by counting all somatic mutations found per tumor (high cutoff ≥ 10 mutations per MB). PD-L1 expression was tested by IHC using PD-L1 antibody clones 22c3 (Agilent; positive cutoff CPS ≥ 10) and SP142 (Ventana; positive cutoff ≥ 5% IC). Pathogenic fusion events were detected using whole transcriptome sequencing (NovaSeq). Statistical significance was determined using the Chi-square test and adjusted for multiple comparison. Results: 538 patients with included – median (range) age 71.5 (30-89) years and 37.5% female/62.5% male. Prevalence of dMMR/MSI-H was 3.9% (21/538) and TMB-high was 22.7% (96/423). Significant molecular differences were not detected in primary vs metastatic disease or in male vs female cases. dMMR/MSI-H tumors had higher frequency of TMB-high compared to MSS tumors (100% vs. 19%, p = 0.00003). dMMR/MSI-H tumors also had a higher frequency than MSS tumors for mutations in genes involved in chromatin remodeling (ASXL 82.4%, CREBBP 60%, SMARCA4 40%, KMT2D 95%, ARIDIA 100%, KMT2A 20%, KMT2C 35.3%, NSD1 20%), DNA-damage repair (FANCG 10%, ATM 45%, ATRX 40%) and other biological pathways (RNF43 10%, PTCH1 21.4%, ERBB3 30%, CDKN2A 25%, TSC2 15%, FLNC 15%, HNF1A 20%, CIC 15%, DNMT3A 17.6%); all adjusted p < 0.05. Pathogenic fusions were detected in 3.8% (17/443) cases, with FGFR3 fusion being the most common, occurring in 2.7% (12/443) cases. PD-L1 positivity was identified in 33.2% (133/400) cases tested by 22c3 antibody and 28.4% (89/313) cases tested by SP142 antibody. No difference was seen in PD-L1 positivity between MSI-H/dMMR vs. MSS tumors. Conclusions: In the largest analysis to date, we found a 3.9% prevalence of dMMR/MSI-high rate in UTUC. All dMMR/MSI-H tumors displayed TMB-high. PD-L1 positivity was comparable between dMMR/MSI-H and MSS tumors. dMMR/MSI-H tumors had a significantly higher rate of mutations in genes involved in chromatin remodeling and DDR biological pathways. These results could inform design of targeted therapy trials in UTUC.

scholarly journals Bringing proportional recovery into proportion: Bayesian modelling of post-stroke motor impairment

Brain ◽  
2020 ◽  
Vol 143 (7) ◽  
pp. 2189-2206 ◽  
Author(s):  
Anna K Bonkhoff ◽  
Thomas Hope ◽  
Danilo Bzdok ◽  
Adrian G Guggisberg ◽  
Rachel L Hawe ◽  
...  
Keyword(s):  
Model Comparison ◽  
Motor Impairment ◽  
Synthetic Data ◽  
Motor Recovery ◽  
Stroke Recovery ◽  
Future Research ◽  
Single Subject ◽  
Post Stroke ◽  
Specific Fraction ◽  
Explained Variance

Abstract Accurate predictions of motor impairment after stroke are of cardinal importance for the patient, clinician, and healthcare system. More than 10 years ago, the proportional recovery rule was introduced by promising that high-fidelity predictions of recovery following stroke were based only on the initially lost motor function, at least for a specific fraction of patients. However, emerging evidence suggests that this recovery rule is subject to various confounds and may apply less universally than previously assumed. Here, we systematically revisited stroke outcome predictions by applying strategies to avoid confounds and fitting hierarchical Bayesian models. We jointly analysed 385 post-stroke trajectories from six separate studies—one of the largest overall datasets of upper limb motor recovery. We addressed confounding ceiling effects by introducing a subset approach and ensured correct model estimation through synthetic data simulations. Subsequently, we used model comparisons to assess the underlying nature of recovery within our empirical recovery data. The first model comparison, relying on the conventional fraction of patients called ‘fitters’, pointed to a combination of proportional to lost function and constant recovery. ‘Proportional to lost’ here describes the original notion of proportionality, indicating greater recovery in case of a more severe initial impairment. This combination explained only 32% of the variance in recovery, which is in stark contrast to previous reports of &gt;80%. When instead analysing the complete spectrum of subjects, ‘fitters’ and ‘non-fitters’, a combination of proportional to spared function and constant recovery was favoured, implying a more significant improvement in case of more preserved function. Explained variance was at 53%. Therefore, our quantitative findings suggest that motor recovery post-stroke may exhibit some characteristics of proportionality. However, the variance explained was substantially reduced compared to what has previously been reported. This finding motivates future research moving beyond solely behaviour scores to explain stroke recovery and establish robust and discriminating single-subject predictions.

Peripheral T cell lymphoma.

1987 ◽  
Vol 5 (5) ◽  
pp. 750-755 ◽  
Author(s):  
R Liang ◽  
D Todd ◽  
T K Chan ◽  
K L Wong ◽  
F Ho ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lymphoma ◽  
Statistical Significance ◽  
Disease Free Survival ◽  
Complete Response ◽  
Small Sample ◽  
T Cell Lymphoma ◽  
Chinese Patients ◽  
Peripheral T Cell Lymphoma ◽  
Small Sample Sizes

Thirty-one Chinese patients with peripheral T cell lymphoma (PTCL) were reviewed. Using the modified Japanese Lymphoma Group classification, there were nine (29%) of the pleomorphic type, 16 (52%) immunoblastic lymphadenopathy (IBL)-like, two (7%) T-zone lymphoma, and one (3%) Lennert's lymphoepithelioid type. Three (9%) were not classifiable. All were positive for T11 (E rosette receptor antigen). Fifty-four percent (15 of 28) were positive predominantly for T4 (helper T cell) and 46% (13/28) for T8 (suppressor T cell). The median age of the patients was 57 years. They usually presented with advanced disease, and while extranodal involvement was common, CNS disease was not seen. The IBL-like type was associated with a positive Coombs' test and polyclonal hypergammaglobulinemia. Five of the nine pleomorphic type were checked for antibody to HTLV-I virus and all were negative. PTCL was associated with poor prognosis, which was not influenced by the histologic subtypes and the T4/T8 phenotypes. The complete response rate of 13 consecutive patients who received the BACOP (bleomycin, doxorubicin, cyclophosphamide, vincristine, and prednisone) L17M regimen was significantly better than the 16 historic controls who received other less-intensive regiments, 84% v 19% (P less than .01). The relapse rate was also significantly lower, 9% v 100% (P less than .001). There appeared to be an improvement in the disease-free survival (DFS) (80% v 0% at 18 months), as well as the overall survival (60% v 36% at 18 months), but the differences did not reach statistical significance due to small sample sizes.

The Predicament of Large Numbers of Observations and How We Got There: Critical Review

2020 ◽  
Author(s):  
Stanley S Levinson
Keyword(s):  
Statistical Significance ◽  
Roc Curves ◽  
Small Sample ◽  
Computational Techniques ◽  
Number Needed To Treat ◽  
Clinical Effects ◽  
Statistical Parameters ◽  
Large Numbers ◽  
Classical Statistics ◽  
Small Sample Sizes

Abstract Background Classical statistics were developed in a time when small sample sizes were the norm; thus, statistical significance typically ensured large clinical effects. Over the past 10–20 years, computational techniques have allowed studies with modest effects to reach statistical significance (usually P &lt; 0.05) by analyzing very large numbers of patients. In this review, I discuss how this came about and provide an intuitive understanding of the strengths and weaknesses of various statistical parameters that provide insight into clinical effect sizes. Content In this review of the literature, a simple web-based program was used for calculations. Examples are shown. Odds and risk ratios are compared with ROC curves to allow better understanding of their predictive value. Summary In these complex times, an intuitive understanding of statistical procedures is increasingly important. This review will attempt to advance the reader’s knowledge so that one can calculate the number needed to treat and its confidence interval, understand the meaning of a modest association, and determine when a study is likely to be accurate but with questionable clinical utility.

Abstract 2806: Does Motor Cortex Activity Predict Motor Recovery? An fMRI Study of Subacute Lacunar Stroke

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Assia Jaillard ◽  
Chantal Delon martin ◽  
Leeanne Carey ◽  
Laurent Lalamalle ◽  
Marc J Hommel ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Recovery ◽  
Small Sample ◽  
Stroke Onset ◽  
Stroke Recovery ◽  
Finger Tapping ◽  
Lacunar Stroke ◽  
Related Activity ◽  
Recovery Score

Background: While primary motor cortex (M1) has been demonstrated to be crucial for motor recovery in a recent meta-analysis including fMRI and TMS studies, other functional neuroimaging studies have found that activity in a broader sensorimotor cortical network correlate with motor recovery. The heterogeneity of stroke lesions and the small sample size characterizing many studies could account for these discrepancies. Hypothesis : The strength of task-related activity in primary motor cortex predicts motor recovery in a clinically homogenous population of acute lacunar stroke patients. Methods: We used fMRI to investigate the neural mechanisms of stroke recovery. We studied 18 stroke patient (4 females, 14 males) after their first single lacunar stroke (7 right , 11 left hemisphere). The lesions caused pure hemiparesia one week after stroke onset (mean 7.2 days; range 2 -15). Lesions were limited to the deep territory of the anterior choroid artery, involving the corticospinal tract at the level of the internal capsule or the corona radiata ( Figure 1 ). Patients were matched to 18 healthy controls for age and sex. Motor impairment was assessed using the NIH Stroke Scale (NIHSS), the Fugl-Meyer Scale (FMS), Finger Tapping Score (FTS), Purdue Pegboard and simple reaction times 7 days and 6 months after stroke. At 6 months, a global motor recovery score was computed using the FMS and the FTS to assess motor recovery. Functional MRI scans were obtained using a self-paced finger tapping (FT) task implemented as a block design alternating right FT, left FT and rest. Data were processed using SPM8. In the first level analysis “FT minus fixation” contrasts were computed for the impaired hand. At the second level, multiple regression was used to assess the effect of the motor recovery score on the FT-related motor activity (threshold p<0.05 FWE; extent threshold k=5). Age and FT rate recorded during the experiment were included as covariates in the second level model. Results: As a group, the patients showed good recovery at 6 months. Both patients and controls exhibited a typical pattern of FT task-related activity. Activity in primary motor cortex predicted motor recovery at 6 months, after adjustment for age and FT rate. MNI coordinates = [-34,-14,48] See Figure 1 . Conclusions: Primary motor cortex activity, measured soon after stroke onset, predicts motor recovery assessed at 6 months post-stroke. fMRI measurements made in the early phase of stroke recovery could be useful to derive prognostic biomarkers in both clinical practice and clinical trials investigating novel treatments, such as stem cell administration.

Abstract 3133: Impact of Post-stroke Isolation on Stroke Outcome

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Venugopal R Venna ◽  
Yan Xu ◽  
Jun Li ◽  
Fudong Liu ◽  
Louise D McCullough
Keyword(s):  
Infarct Size ◽  
Functional Recovery ◽  
Forced Swim Test ◽  
Statistical Significance ◽  
Experimental Studies ◽  
Stroke Recovery ◽  
Stroke Outcome ◽  
Post Stroke ◽  
The Impact

Background: Psychosocial factors are increasingly accepted as critical factors in post-stroke recovery, mortality and morbidity. Although, emerging data from clinical and population based studies support the role of social support in improved functional recovery and reducing the risk of mortality, to date no experimental studies have investigated such effects in post-stroke animal models. The aim of this study is to investigate for the impact of post stroke housing and the effects of long-term social isolation and pair housing with either a healthy or a stroked partner, and explored for the mechanisms. Methods: Male mice (20-25g; C57BL/6N, Charles River Labs), all initially pair housed, were subjected to right middle cerebral artery occlusion (MCAO - 60min) and then randomly assigned to a specific housing condition - isolated, paired with a stroke partner or paired with a healthy partner. Infarct size was quantified with TTC 72h after stroke (n=8/grp). We then investigated the effects of housing on long-term functional recovery using corner test, cylinder test, forced swim test (FST) and tail suspension test (TST). We further explored the mechanisms underlying the improved behavioral recovery by injecting BrDU 150mg/kg/day i.p. for 5 days starting from day 3 post-stroke (n=8/grp), and assessing changes in BDNF levels by western-blot analysis (n=4/grp). Data were expressed as mean±sem. Two-way ANOVA was performed and P value < .05 was set for statistical significance. Results: Post-stroke housing conditions can significantly impact infarct size; we observed that mice isolated after stroke had increased infarct volume compared to pair housed mice in all three brain regions (Cortex: 63.2±2.5 vs 40.0±6.2; p<0.01); (Striatum: 86.6±2.2 vs 67.7±2.9; p<0.01); (Total: 60.9±1.3 vs 32.6±4.3; p<0.01). Although post-stroke housing with healthy vs a stroked partner did not influenced infarct size (p>0.05), animals pair housed with healthy partner showed a significantly improved functional recovery by as early as day 15 in the cylinder and corner tests (p<0.05). Increased mobility was observed in FST and TST in PH mice compared to SI mice at day 90 (p<0.05). Consistently, housing with a healthy partner increased BrDU positive cells (p<0.05) and enhanced BDNF expression compared to other cohorts (SI 1±0.1; PH with stroke partner 1.9±0.2; PH with healthy partner 2.6±0.1; n=4/grp), no changes were seen in sham mice. Conclusions: Post-stroke housing has an important impact on stroke outcome; isolation has a detrimental effect on infarct size compared to pair housed cohorts. Interestingly, independent of infarct size, housing with a healthy partner hastened recovery compared to those stroke mice housed with partner that had also been subjected to stroke. Molecular analysis indicates the involvement of BDNF and neurogenesis may be important regulators of post-stroke housing induced functional recovery.

Abstract TMP31: Peripheral Nerve Stimulation Paired with Constraint-Induced Therapy to Enhance Post-Stroke Upper Extremity Motor Performance

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Cheryl Carrico ◽  
KC Chelette ◽  
Laurie Nichols ◽  
Lumy Sawaki
Keyword(s):  
Peripheral Nerve ◽  
Upper Extremity ◽  
Motor Function ◽  
Nerve Stimulation ◽  
Motor Performance ◽  
Motor Recovery ◽  
Peripheral Nerve Stimulation ◽  
Motor Deficit ◽  
Motor Training ◽  
Post Stroke

Research has shown that peripheral nerve stimulation (PNS) can enhance motor learning following cortical lesions. Studies have also shown that intensive upper extremity motor training can significantly enhance post-stroke motor performance. Constraint-induced therapy (CIT) is a form of intensive training that restricts use of the non-paretic upper extremity during repetitive, task-oriented motor training of the paretic extremity. Extensive evidence has validated the effectiveness of CIT for enhancing post-stroke upper extremity motor recovery. No studies have evaluated how PNS may modulate the effects of CIT. Therefore, we conducted a pilot study of PNS paired with CIT and hypothesized that in subjects with stroke, pairing CIT with active PNS would lead to significantly more improved motor function in the paretic upper extremity than CIT paired with sham PNS. Outcome measures included the Fugl-Meyer Assessment Scale (FMA; primary outcome measure), the Wolf Motor Function Test (WMFT), and the Action Research Arm Test (ARAT). Nineteen chronic stroke subjects with mild to moderate upper extremity motor deficit received 2 hours of either active (n=10) or sham (n=9) PNS preceding 4 hours of CIT for 10 consecutive weekdays. Changes in FMA, WMFT, and ARAT were analyzed using factorial ANOVA. Results showed significant (p<0.05) change in all measures at completion evaluation compared with baseline (FMA (p=0.005); WMFT (p=0.030); ARAT (p=0.020)) as well as 1-month follow-up compared with baseline (FMA (p=0.048); WMFT (p=0.045); ARAT (p=0.047)). These results highlight the enormous potential for PNS paired with CIT to enhance post-stroke upper extremity motor recovery more effectively than CIT alone.

Abstract P212: Admission National Institutes of Health Stroke Scale Associated With Higher Rates of Post Stroke Depression Independent of Imaging Characteristics

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Muhammad M Alvi ◽  
Ashley Petrone ◽  
Jessica Frey
Keyword(s):  
Small Vessel Disease ◽  
Small Sample Size ◽  
Small Sample ◽  
National Institutes Of Health ◽  
Stroke Recovery ◽  
Post Stroke ◽  
Imaging Characteristics ◽  
Significant Difference ◽  
Patient Health ◽  
Post Stroke Depression

Introduction: The etiology of post-stroke depression (PSD) is still not fully understood. It is well known that leukoaraiosis is associated with cognitive decline and depression, but currently unclear if lacunar strokes, thought to be caused by small vessel disease, have higher rates of PSD. A better understanding of PSD etiology can lead to improved treatment of PSD and subsequently better stroke recovery. Methodology: Out of 159 patients that were successfully contacted via phone within 3 months of discharge, there were 22 identified as having an acute stroke or TIA and scored ≥ 2 on the Patient Health Questionnaire (PHQ) assessment. MRI brain was reviewed for stroke size, location, periventricular and deep white matter fazekas score, number of microbleeds, and chronic lacunar strokes. Admission and discharge National Institutes of Health (NIH) stroke scale and stroke etiology were also recorded. Results: There was a significantly positive correlation between NIH score at admission and PHQ2 score (r = 0.184, p =0.044), demonstrating that patients with NIH ≥ 6 are 4.6 times more likely to develop PSD than a patient with NIH < 6 (Odds ratio (OR) = 4.6, CI [1.284-16.591]). There was no significant difference between PSD incidence in stroke size or location. Although not statistically significant, there was a suggestion of more PSD seen in cortical, cardioembolic, and cryptogenic strokes as well as fazekas score ≥ 2 and old lacunar infarcts. The table summarizes characteristics of the 7 TIA and 15 stroke patients suffering from PSD with PHQ ≥ 2: Conclusion: Initial NIH significantly predicted PSD irrespective of leukoaraiosis. This study was limited by the small sample size which could be due to under-diagnosis of PSD. In conclusion, admission NIH is associated with higher rates of PSD, but the underlying etiology is likely multifactorial given the suggestion of higher rates of PSD with higher fazekas score, and cortical, cardioembolic, and cryptogenic strokes.

scholarly journals Comparative Evaluation of a Novel Concept Design Method

2013 ◽  
Author(s):  
Damian Rogers ◽  
Filippo A. Salustri
Keyword(s):  
Design Method ◽  
Statistical Significance ◽  
Small Sample ◽  
Design Methods ◽  
Concept Design ◽  
Sample Sizes ◽  
Pilot Experiment ◽  
Small Sample Sizes ◽  
Novel Concept ◽  
Future Work

Based on their previous work in creating a new method of design, termed the “Design by DNA” method, the authors are now experimentally validating the method against other, known methods. The goal of the experiment is to determine if Design by DNA promotes creative designs. Specifically, the authors are seeking to measure and compare creativity resulting from the use of Design by DNA and from other, known design methods. However, few have conducted empirical experiments in the past, and further, the literature on comparatively evaluating creativity of different design methods is relatively sparse. Therefore, the authors are developing a framework for defining and executing meaningful experiments that can accommodate various design methods, including Design by DNA, and also provide meaningful data to comparatively evaluate those methods, with the goal of determining whether Design by DNA impacts creativity in design. The experimental framework is described, and results of a pilot experiment are given. In that framework, creativity was characterized by novelty, usefulness, and cohesion. Due to small sample sizes, confidence in the results is not particularly high. Even so, some results do indicate several points of interest. An analysis of the results suggests that Design by DNA can offer advantages in engineering design, ranking higher in both the ‘usefulness’ and ‘cohesion’ categories of the creativity assessment. Hypotheses are given to explain why the experimental results show the slightly lower score in the ‘novelty’ category. Experiment participants were also evaluated on the NASA Task Loading Index (TLX) to evaluate how taxed they were using the different design methods and results are shown. Here, the Design by DNA method accrues better scores in 5 of the 6 NASA TLX categories, suggesting that it was less strenuous on the participants than the other methods. Statistical analysis of both the creativity scores and the TLX document shows confidence levels of between 65% and 96%, which is acceptable for very low populations. As this was a pilot experiment, the authors foresee future work to improve the results presented here. First, larger sample sizes are needed to improve statistical significance of our conclusions. Secondly, the authors wish to set out a series of experiments whereby each test is run by pitting one specific design method against the Design by DNA method, to better show a 1-on-1 comparison between the methods and highlight the strengths and weaknesses of each.

Sign in / Sign up

Export Citation Format

Share Document