scholarly journals Intra-individual Variability as a Measure of Information Processing Difficulties in Multiple Sclerosis

2012 ◽  
Vol 14 (2) ◽  
pp. 77-83 ◽  
Author(s):  
Magdalena Wojtowicz ◽  
Lindsay I. Berrigan ◽  
John D. Fisk
Keyword(s):  
Multiple Sclerosis ◽  
Information Processing ◽  
Cognitive Functioning ◽  
Coefficient Of Variation ◽  
Individual Variability ◽  
Group Differences ◽  
Information Processing Speed ◽  
Subject Variability ◽  
Level Performance ◽  
Within Subject Variability

Deficits in information processing speed are among the most commonly reported impairments in multiple sclerosis (MS) and are generally assessed by evaluating mean-level performance on time-limited tests. However, this approach to assessing performance ignores potential within-subject differences in MS patients that may be useful for characterizing cognitive difficulties in MS. An alternative method of measuring performance is by examining the degree of within-subject variability, termed intra-individual variability (IIV). Intra-individual variability provides information about the characteristics of a person's performance over time and may provide novel information about cognitive functioning in MS. This study examined IIV in performance on the Computerized Test of Information Processing (CTIP) using two within-subject variability methods: individual standard deviation and coefficient of variation. Eighteen females with relapsing-remitting MS and 18 healthy female controls completed the CTIP. Consistent with previous research, MS patients demonstrated slower overall mean performance on the CTIP compared with controls, with patients becoming increasingly slower than controls as cognitive demands increased across the tasks. Furthermore, MS patients demonstrated greater IIV as measured by individual standard deviations on all subtests of the CTIP, even with mean-level group differences as well as practice and learning effects controlled. These between-group differences were not found when the coefficient of variation, a more coarse measure of within-subject variability, was used. Intra-individual variability was also found to be a better predictor of neurologic status than mean-level performance. These results suggest that IIV may provide unique insight into cognitive functioning in MS.

Indices of Cognitive Dysfunction in Relapsing-Remitting Multiple Sclerosis: Intra-individual Variability, Processing Speed, and Attention Network Efficiency

2013 ◽  
Vol 19 (5) ◽  
pp. 551-558 ◽  
Author(s):  
Magdalena Wojtowicz ◽  
Antonina Omisade ◽  
John D. Fisk
Keyword(s):  
Multiple Sclerosis ◽  
Information Processing ◽  
Processing Speed ◽  
Cognitive Abilities ◽  
Individual Variability ◽  
Information Processing Speed ◽  
Network Efficiency ◽  
Processing Efficiency ◽  
Attention Network ◽  
Relapsing Remitting

AbstractImpairments in attention and information processing speed are common in multiple sclerosis (MS) and may contribute to impairments of other cognitive abilities. This study examined attentional efficiency, information processing speed and intra-individual variability in response speed using the Attention Network Test-Interactions (ANT-I) in mildy-affected patients with MS. Thirty-one patients with relapsing-remitting MS and 30 age, sex, and education-matched controls completed the ANT-I, as well as the Paced Auditory Serial Attention Test (PASAT), as a standard clinical measure of information processing efficiency. As expected, patients with MS were slower in reaction time performance on the ANT-I and had poorer performance on the PASAT compared to controls. Patients with MS also demonstrated poorer efficiency in their executive control of attention on the ANT-I, suggesting difficulties with top-down allocation of attention. In addition, the MS group demonstrated greater intra-individual variability in the responses to the ANT-I even when their slower overall response time and other factors such as practice were accounted for. Intra-individual variability was found to best predict group membership compared to PASAT scores and other ANT-I scores. These results suggest that intra-individual variability may provide sensitive, unique and important information regarding cognitive functioning in early MS. (JINS, 2013, 19, 1–8)

scholarly journals Do Cardiovascular Risk Factors and Cardiovascular Disease Explain Sex Differences in Cognitive Functioning in Old Age?

2021 ◽  
pp. 1-13
Author(s):  
Elisabeth Maria van Zutphen ◽  
Judith Johanna Maria Rijnhart ◽  
Didericke Rhebergen ◽  
Majon Muller ◽  
Martijn Huisman ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cardiovascular Disease ◽  
Sex Differences ◽  
Information Processing ◽  
Cardiovascular Risk ◽  
Episodic Memory ◽  
Cognitive Functioning ◽  
Cardiovascular Risk Factors ◽  
Processing Speed ◽  
Information Processing Speed

Background: Sex differences in cognitive functioning in old age are known to exist yet are still poorly understood. Objective: This study examines to what extent differences in cardiovascular risk factors and cardiovascular disease between men and women explain sex differences in cognitive functioning. Methods: Data from 2,724 older adults from the Longitudinal Aging Study Amsterdam were used. Information processing speed and episodic memory, measured three times during six years of follow-up, served as outcomes. The mediating role of cardiovascular risk factors and cardiovascular disease was examined in single and multiple mediator models. Determinant-mediator effects were estimated using linear or logistic regression, and determinant-outcome and mediator-outcome effects were estimated using linear mixed models. Indirect effects were estimated using the product-of-coefficients estimator. Results: Women scored 1.58 points higher on information processing speed and 1.53 points higher on episodic memory. Several cardiovascular risk factors had small mediating effects. The sex difference in information processing speed was mediated by smoking, depressive symptoms, obesity, and systolic blood pressure. The sex difference in episodic memory was mediated by smoking, physical activity, and depressive symptoms. Effects of smoking, LDL cholesterol, and diabetes mellitus on information processing speed differed between men and women. Conclusion: Differences in cardiovascular risk factors between women and men partially explained why women had better cognitive functioning. A healthy cardiovascular lifestyle seems beneficial for cognition and sex-specific strategies may be important to preserve cognitive functioning at older age.

Difficulties in Planning Among Patients with Multiple Sclerosis: A Relative Consequence of Deficits in Information Processing Speed

2013 ◽  
Vol 19 (5) ◽  
pp. 613-620 ◽  
Author(s):  
Emily M. Owens ◽  
Douglas R. Denney ◽  
Sharon G. Lynch
Keyword(s):  
Multiple Sclerosis ◽  
Information Processing ◽  
Processing Speed ◽  
Healthy Controls ◽  
Problem Difficulty ◽  
Sufficient Time ◽  
Information Processing Speed ◽  
Tower Of London ◽  
Planning Ability

AbstractPrevious studies show that MS patients take longer than healthy controls to plan their solutions to Tower of London (TOL) problems but yield conflicting results regarding the quality of their solutions. The present study evaluated performance under untimed or timed conditions to assess the possibility that differences in planning ability only occur when restrictions in solution times are imposed. MS patients (n = 39) and healthy controls (n = 43) completed a computerized version of the TOL under one of two conditions. In the untimed condition, participants were allowed as much time as needed on each problem. In the timed condition, limits were imposed on solution times and time remaining was displayed with each problem. Patients exhibited longer planning times than controls, and the disparity between groups increased with problem difficulty. Planning performance depended upon condition. In the untimed condition, patients and controls performed equally well. When solution times were restricted, however, patients solved fewer problems than controls. MS patients’ planning ability is intact when permitted sufficient time to formulate the required plan. Deficiencies in planning are only evident when time is restricted, and, therefore, are more accurately considered a relative consequence of disease-related problems in information processing speed. (JINS, 2013, 19, 1–8)

Effect of dalfampridine on information processing speed impairment in multiple sclerosis

Neurology ◽  
2019 ◽  
Vol 93 (8) ◽  
pp. e733-e746 ◽  
Author(s):  
Laura De Giglio ◽  
Francesca De Luca ◽  
Flavia Gurreri ◽  
Ilaria Ferrante ◽  
Luca Prosperini ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Information Processing ◽  
Processing Speed ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Controlled Trial ◽  
Information Processing Speed ◽  
Effective Treatment Option ◽  
Double Blind ◽  
To Receive

ObjectiveTo test a possible benefit of dalfampridine on information processing speed (IPS), a key function for cognitive impairment (CogIm) in multiple sclerosis (MS).MethodsIn this randomized, double-blind, placebo-controlled trial, we included patients with a score on the Symbol Digit Modalities Test (SDMT) under the 10th percentile of the reference value. Patients were randomized in a 2:1 ratio to receive dalfampridine 10 mg or placebo twice daily for 12 weeks. They underwent a comprehensive neuropsychological evaluation at screening (T0), at the end of treatment (T1), and after a 4-week follow-up (T2). The primary endpoint was improvement in SDMT.ResultsOut of 208 patients screened, 120 were randomized to receive either dalfampridine (n = 80) or placebo (n = 40). At T1, the dalfampridine group presented an increase of SDMT scores vs placebo group (mean change 9.9 [95% confidence interval (CI) 8.5–11.4] vs 5.2 [95% CI 2.8–7.6], p = 0.0018; d = 0.60 for raw score; and 0.8 [95% CI 0.6–1] vs 0.3 [95% CI 0.0–0.5], p = 0.0013; d = 0.61 for z scores; by linear mixed model with robust standard error). The improvement was not sustained at T2. A beneficial effect of dalfampridine was observed in the Paced Auditory Serial Addition Test and in cognitive fatigue.ConclusionDalfampridine could be considered as an effective treatment option for IPS impairment in MS.Trial registration2013-002558-64 EU Clinical Trials Register.Classification of evidenceThis study provides Class I evidence that for patients with MS with low scores on the SDMT, dalfampridine improves IPS.

Reproducibility of the growth hormone response to stimulation with growth hormone-releasing hormone plus arginine during lifespan

1996 ◽  
Vol 135 (5) ◽  
pp. 568-572 ◽  
Author(s):  
Maria Rosa Valetto ◽  
Jaele Bellone ◽  
Claudia Baffoni ◽  
Paola Savio ◽  
Gianluca Aimaretti ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Normal Subjects ◽  
Individual Variability ◽  
Hormone Response ◽  
Female Age ◽  
Releasing Hormone ◽  
Gh Secretion ◽  
Subject Variability ◽  
Within Subject Variability

Valetto MR, Bellone J, Baffoni C, Savio P, Aimaretti G, Gianotti L, Arvat E, Camanni F, Ghigo E. Reproducibility of the growth hormone response to stimulation with growth hormone-releasing hormone plus arginine during lifespan. Eur J Endocrinol 1996;135:568–72. ISSN 0804–4643 The reliability and reproducibility of provocative stimuli of growth hormone (GH) secretion in the diagnosis of GH deficiency are still controversial both in childhood and in adulthood. The combined administration of GH-releasing hormone (GHRH) and arginine (ARG), which likely acts via inhibition of hypothalamic somatostatin release, is one of the most potent stimuli known so far and has been proposed recently as the best test to explore the maximal somatotrope capacity of somatotrope cells. However, it is well known that, usually, provocative stimuli of GH secretion suffer from poor reproducibility and that of the GHRH + ARG test has still to be verified. We aimed to verify the between- and within-subject variability of the GH response to the GHRH + ARG test in normal subjects during their lifespan as well as in hypopituitaric patients with GH deficiency (GHD). In 10 normal children (C: six male and four female, age 12.3 ± 0.9 years, body mass index (BMI) = 16.6 ± 0.7 kg/m2, pubertal stages I-III), 18 normal young adults (Y: ten male and eight female, age 31.1 ± 1.3 years, BMI = 21.4 ± 0.4 kg/m2), 12 normal elderly subjects (E: two male and ten female, age 74.4 ± 1.8 years, BMI= 22.6 ± 0.6 kg/m2) and 15 panhypopituitaric GH-deficient patients (GHD: nine male and six female, age 40.9 ± 4.1 years, BMI= 22.7 ± 1.0 kg/m2), we studied the inter- and intra-individual variability of the GH response to GHRH (1 μg/kg iv) + ARG (0.5 g/kg iv) in two different sessions at least 3 days apart. The GH responses to GHRH + ARG in C (1st vs 2nd session: 61.6 ± 8.1 vs 66.5 ± 9.4 μg/l), Y (70.4 ± 10.1 vs 76.2 ± 10.7 μg/l) and E (57.9 ± 14.8 vs 52.1 ± 8.0 μg/l) were similar and reproducible in all groups. The somatotrope responsiveness to GHRH + ARG also showed a limited within-subject variability (r = 0.71, 0.90 and 0.89 and p < 0.02, 0.0005 and 0.0005 for C, Y and E, respectively). Similarly in GHD, the GH response to the GHRH + ARG test showed a good inter- (1st vs 2nd session: 2.3 ± 0.5 vs 2.2 ± 0.6 μg/l) and intra-individual reproducibility (r = 0.70, p < 0.005). The GHRH + ARG-induced GH responses in GHD were markedly lower (p < 0.0005) than those in age-matched controls and no overlap was found between GH peak responses in GHD and normal subjects. In normal subjects, the GH response to GHRH + ARG is very marked, independent of age and shows limited inter- and intra-individual variability. The GH response to the GHRH + ARG test is strikingly reduced in panhypopituitaric patients with GHD, in whom the low somatotrope responsiveness is reproducible. Thus, these findings strengthen the hypothesis that GHRH + ARG should be considered the most reliable test to evaluate the maximal secretory capacity of somatotrope cells and to distinguish normal subjects from GHD patients in adulthood. E. Ghigo, Divisione di Endocrinologia, Ospedale Molinette, C.so Dogliotti 14, 10126, Torino, Italy

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