Information Processing Speed In Patients Research Articles

Outcomes of the effect of exercise on cognitive function in patients with depression: A meta-analysis.

Major depressive disorder is a common mental disorder, characterized by a high rate of suicide and recurrence, which is frequently accompanied by cognitive impairments, particularly in executive function, memory, attention, and information processing speed. As such, improving the cognitive function in patients with depression and enhancing their quality of life are urgent issues. To perform a systematic review and meta-analysis of the effects of exercise on cognitive function in patients with depression. The PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure, Wanfang Medical, VIP, and Biomedical Databases for randomized controlled trials (RCTs) databases were searched (from inception to October 19, 2023) for studies investigating improvements in cognitive function in patients with depression through exercise. Tools recommended by the Cochrane Handbook for RCT evaluation, and GRADEpro and Stata17 software, were employed for risk of bias assessment, evidence grading, forest plot construction, subgroup and sensitivity analyses, and assessment of publication bias. Seventeen RCTs (1173 patients with depression) were included. Exercise had a small but significant positive effect on attention, with an effect size of 0.21, 95%CI: 0.07-0.34, P < 0.01. Specifically, aerobic exercise regimens of 30-60 minute/session, thrice a week, at moderate intensity, and sustained over 3-12 weeks, were associated with the most pronounced benefits (P < 0.05), with effect sizes for executive function, memory, and information processing speed of 0.11, 95%CI: -0.11-0.32, P = 0.34; 0.08, 95%CI: 0.00-0.16, P = 0.05; and 0.14, 95%CI: 0.04-0.25, P = 0.01, respectively. The evidence levels for attention, information processing speed, and memory were rated as 'low,' whereas that for executive function was rated as 'very low'. Exercise could improve attention and information-processing speed in patients with depression, although improvements in executive function and memory are not significant.

Glymphatic dysfunction mediates the influence of choroid plexus enlargement on information processing speed in patients with white matter hyperintensities.

Glymphatic dysfunction has been correlated with cognitive decline, with a higher choroid plexus volume (CPV) being linked to a slower glymphatic clearance rate. Nevertheless, the interplay between CPV, glymphatic function, and cognitive impairment in white matter hyperintensities (WMHs) has not yet been investigated. In this study, we performed neuropsychological assessment, T1-weighted three-dimensional (3D-T1) images, and diffusion tensor imaging (DTI) in a cohort of 206 WMHs subjects and 43 healthy controls (HCs) to further explore the relationship. The DTI analysis along the perivascular space (DTI-ALPS) index, as a measure of glymphatic function, was calculated based on DTI. Severe WMHs performed significantly worse in information processing speed (IPS) than other three groups, as well as in executive function than HCs and mild WMHs. Additionally, severe WMHs demonstrated lower DTI-ALPS index and higher CPV than HCs and mild WMHs. Moderate WMHs displayed higher CPV than HCs and mild WMHs. Mini-Mental State Examination, IPS, and executive function correlated negatively with CPV but positively with DTI-ALPS index in WMHs patients. Glymphatic function partially mediated the association between CPV and IPS, indicating a potential mechanism for WMHs-related cognitive impairment. CPV may act as a valuable prognostic marker and glymphatic system as a promising therapeutic target for WMHs-related cognitive impairment.

Effects of Type 2 Diabetes on the Neuropsychological Profile in Mild Cognitive Impairment.

Diabetes is one of the main risk factors for developing mild cognitive impairment (MCI) and Alzheimer's disease. Most studies have demonstrated a worse performance in executive function, verbal fluency, and information processing speed in patients with diabetes. To assess the cognitive functioning of persons with type 2 diabetes and amnesic mild cognitive impairment (aMCI-T2DM) compared to persons with aMCI without diabetes and persons without diabetes or aMCI as controls, to understand the role of diabetes in the neuropsychological profile. Cross-sectional study involving a sample of 83 patients, ranging in age from 61 to 85 years and divided into three groups: aMCI-T2DM (27 patients), aMCI (29 patients), Controls (27 individuals). All the participants undertook an exhaustive neuropsychological assessment (auditory-verbal and visual memory, attention, information processing speed, language, executive function, and depression). Both groups of aMCI patients performed significantly worse than the controls in all the neuropsychological tests. A significant linear tendency (p trend < 0.05) was found between groups, with the aMCI-T2DM group presenting worse results in global cognition assessed by the Mini-Mental State Examination and Montreal Cognitive Assessment; Rey-Osterrieth Complex Figure Test; Auditory Verbal Learning Test; Trail Making Test A and B, Verbal Fluency Test, and Hamilton Depression Rating Scale. aMCI patients with or without diabetes showed worse cognitive function compared to persons without diabetes or aMCI. Additionally, aMCI patients without T2DM presented a different cognitive profile than aMCI patients with T2DM, which tended towards presenting worse cognitive functions such as global cognition, memory, attention, executive function, and language.

Metabolite changes in prefrontal lobes and the anterior cingulate cortex correlate with processing speed and executive function in Parkinson disease patients.

BackgroundProcessing speed and executive function can be impaired in patients with Parkinson disease (PD). However, the neural factors related to the slowdown in processing speed and dysexecutive function in PD are not completely understood. The objective of this study is to investigate the metabolic changes of the frontal and anterior cingulate cortex (ACC) through the use of 1H magnetic resonance spectroscopy and to explore the association between cognitive function and metabolic ratios.MethodsIn this retrospective case-control study, we conducted neuropsychological assessments of executive function and information processing speed in healthy controls (HCs) and in patients with PD. Chemical information was obtained for the of N-acetyl-aspartate (NAA):creatine (Cr) ratio and the choline-containing compounds (Cho):Cr ratio within the bilateral prefrontal cortex and ACC. Using hierarchical multiple regression analysis, we analyzed the relationship between cognitive function and metabolic ratios in the bilateral prefrontal lobe and ACC in patients with PD.ResultsIn all, 59 patients with PD and 30 HCs were recruited. Patients with PD showed worse performance in executive function and processing speed compared with HCs (P<0.001). In patients with PD, the Cho:Cr ratios in the ACC (Z=2.20, P=0.028) and the right prefrontal cortex (t=2.16, P=0.034) were significantly increased. The hierarchical multiple regressions in patients with PD showed that the NAA:Cr ratio in the ACC correlated with the Stroop A completion times (P<0.05) and that the NAA:Cr ratio of the right prefrontal cortex correlated with the scores of the Wechsler Adult Intelligence Scale (WAIS)-Digit symbol test (P<0.05).ConclusionsInformation processing speed and executive function are impaired in patients with PD. Neuronal integrity and membrane turnover in the ACC and the right prefrontal cortex may be important factors in the slowdown of the information processing speed in patients with PD.

T1 Relaxation Times in the Cortex and Thalamus Are Associated With Working Memory and Information Processing Speed in Patients With Multiple Sclerosis.

Background: Cortical and thalamic pathologies have been associated with cognitive impairment in patients with multiple sclerosis (MS).Objective: We aimed to quantify cortical and thalamic damage in patients with MS using a high-resolution T1 mapping technique and to evaluate the association of these changes with clinical and cognitive impairment.Methods: The study group consisted of 49 patients with mainly relapsing-remitting MS and 17 age-matched healthy controls who received 3T MRIs including a T1 mapping sequence (MP2RAGE). Mean T1 relaxation times (T1-RT) in the cortex and thalami were compared between patients with MS and healthy controls. Additionally, correlation analysis was performed to assess the relationship between MRI parameters and clinical and cognitive disability.Results: Patients with MS had significantly decreased normalized brain, gray matter, and white matter volumes, as well as increased T1-RT in the normal-appearing white matter, compared to healthy controls (p < 0.001). Partial correlation analysis with age, sex, and disease duration as covariates revealed correlations for T1-RT in the cortex (r = −0.33, p < 0.05), and thalami (right thalamus: r = −0.37, left thalamus: r = −0.50, both p < 0.05) with working memory and information processing speed, as measured by the Symbol-Digit Modalities Test.Conclusion: T1-RT in the cortex and thalamus correlate with information processing speed in patients with MS.

The Possible Direct Correlation between Cognitive Impairment and Fear of Catching COVID-19 among Patients with Multiple Sclerosis.

Objective: The prevalence of cognitive impairment in multiple sclerosis (MS) is significant and it is estimated that 40% to 70% of patients with MS suffer from this impairment. COVID-19 is also a new infectious disease. The symptoms of this disease, which include fever, shortness of breath, and cough, can be mild to severe and can even lead to death. Due to the use of immunosuppressive drugs by Patients with MS, they might be at greater risk of catching COVID-19. Thus, patients with MS may be more afraid of catching the virus. One of the important factors is the relationship between cognitive deficit and the increase in patients' fear of COVID-19. The aim of this study was to assess the relationship between fear of catching COVID-19 and cognitive impairment in patients with MS.Method: This cross-sectional study was conducted at the MS Clinic, Sina hospital, Tehran University of Medical Sciences, Tehran, Iran. Our participants in this project were Patients with MS who were over 18 years old and had no history of other neurological and psychiatric diseases. In addition to obtaining demographic and clinical information, we measured the fear of catching the COVID 2019 via Fear of COVID-19 Scale (FCV-19S), which is 7-item questionnaire. We also used Multiple Sclerosis Neuro Psychological Screening Questionnaire (MSNQ) to assess memory and information processing speed in Patients with MS.Results: After adjustment for age, gender, disease duration, highest level of education, MS type, and EDSS in linear regression model, as well as the MSNQ total score and fear score of catching coronavirus, the results demonstrated a significant positive correlation with P value of 0.00 and β: 0.024.Conclusion: The present study showed a direct relationship between cognitive disorder and level of fear regarding COVID-19. Patients with more cognitive disorders were more afraid of COVID-19.

The associations between regional cortical atrophies and information processing speed in patients with relapsing-remitting multiple sclerosis

The associations between regional cortical atrophies and information processing speed in patients with relapsing-remitting multiple sclerosis

Structural MRI correlates of PASAT performance in multiple sclerosis

BackgroundThe Paced Auditory Serial Addition Test (PASAT) is a useful cognitive test in patients with multiple sclerosis (MS), assessing sustained attention and information processing speed. However, the neural underpinnings of performance in the test are controversial. We aimed to study the neural basis of PASAT performance by using structural magnetic resonance imaging (MRI) in a series of 242 patients with MS.MethodsPASAT (3-s) was administered together with a comprehensive neuropsychological battery. Global brain volumes and total T2-weighted lesion volumes were estimated. Voxel-based morphometry and lesion symptom mapping analyses were performed.ResultsMean PASAT score was 42.98 ± 10.44; results indicated impairment in 75 cases (31.0%). PASAT score was correlated with several clusters involving the following regions: bilateral precuneus and posterior cingulate, bilateral caudate and putamen, and bilateral cerebellum. Voxel-based lesion symptom mapping showed no significant clusters. Region of interest–based analysis restricted to white matter regions revealed a correlation with the left cingulum, corpus callosum, bilateral corticospinal tracts, and right arcuate fasciculus. Correlations between PASAT scores and global volumes were weak.ConclusionPASAT score was associated with regional volumes of the posterior cingulate/precuneus and several subcortical structures, specifically the caudate, putamen, and cerebellum. This emphasises the role of both cortical and subcortical structures in cognitive functioning and information processing speed in patients with MS.

T143. NOT A NUISANCE ANY MORE: GLOBAL FMRI SIGNAL AT REST, PROCESSING SPEED AND SYMPTOM SEVERITY IN SCHIZOPHRENIA

BackgroundBefore data from resting-state functional magnetic resonance imaging (rs-fMRI) is analyzed, the global signal (GS) - average blood-oxygen level dependent (BOLD) signal across all voxels in the brain - is normally removed through global signal regression (GSR). This convention arose in order to control for changes in brain activity that are usually of no interest but may be caused by non-neuronal factors, including changes in respiratory rate, arterial CO2 levels or cardiac pulsation. However, recent studies have indicated that GS may systematically vary between patients with schizophrenia and healthy controls. In addition to testing this notion, we also studied if the dynamic variance of global signal across time carried any meaningful information that relates to overall symptom severity and information processing speed in patients with schizophrenia.MethodsData was collected from 39 in a clinically stable, medicated early stage of schizophrenia (median duration of illness= 6.5 years), and 34 sex, age and parental socioeconomic-status matched healthy controls over a 10-minute period of eyes-open rest at TR=2.5s (3T Philips Achieva, 240 time points, dual-echo, gradient-echo EPI). Scores were obtained from the Signs and Symptoms of Psychotic Illness (SSPI) scale and the Digit Symbol Substitution Test (DSST). Rs-fMRI time-series data were motion-corrected (using 6 parameters), slice-time corrected, reoriented with structural images, band-pass filtered (0.01–0.1 Hz), scrubbed using ArtRepair for framewise displacement and transformed to MNI space. SPM8 and the advanced version of the Data Processing Assistant for resting-state fMRI (DPARSFA) were used for this purpose. GS mean was computed from all grey matter voxels using a template mask in MNI space, using grand mean scaling to a base of 1000, averaged across all time-points. The variance of GS across time (dynamic GS variance) was computed from the entire 10-minutes of acquisition (240 time points).ResultsIndependent-sample t-tests used to compare GS mean between controls (mean[sd] = 3135.1[1244.4]) and the SCZ group (mean[sd] = 3207.8[1191.7]) yielded no significant results [t(71) = -0.14, p = .89]. The temporal variance of GS did not differ between controls (mean[sd] = 113.05[59.41]) and the SCZ group (mean[sd] = 118.02[57.93]) [t(71) = -0.36, p = .72]. In the SCZ group there was a significant correlation between the total SSPI score reflecting overall illness severity (□ = -.322, p < 0.05) and the mean GS. This relationship was especially pronounced for the syndrome of Reality Distortion (rho = -.344, p < 0.05) and Disorganization (rho = -.303, p = 0.065), where higher symptom severity was seen in patients with lower mean GS.Dynamic variance in GS was higher in healthy controls with lower mean DSST (r = -.364, p = 0.04), but no such relationship was seen in the SCZ group (r = .066, p = .694). Notably, when compared to controls (mean[sd] = 57.4[9.40]), patients (mean[sd]=42.4[9.97]) had significantly lower DSST scores [t(69) = 6.47, p < 0.001]. Neither GS nor GS variance related to root mean square of framewise displacement in the 2 groups.DiscussionWe did not find an overall increase or reduction in the global signal in patients with schizophrenia. Nevertheless, the strength of global signal obtained from resting fMRI is related to severity of persisting symptoms of schizophrenia, whereas the dynamic variance of this signal relates to the speed of processing ability assessed outside the scanner in healthy subjects. With emerging evidence relating global signal to cognitive vigilance and overall brain connectivity, our results indicate that global signal is a parameter of interest that should not be automatically discarded in resting fMRI studies of schizophrenia

Development of a Tablet-based symbol digit modalities test for reliably assessing information processing speed in patients with stroke

Purpose: To develop a Tablet-based Symbol Digit Modalities Test (T-SDMT) and to examine the test–retest reliability and concurrent validity of the T-SDMT in patients with stroke.Methods: The study had two phases. In the first phase, six experts, nine college students and five outpatients participated in the development and testing of the T-SDMT. In the second phase, 52 outpatients were evaluated twice (2 weeks apart) with the T-SDMT and SDMT to examine the test–retest reliability and concurrent validity of the T-SDMT.Results: The T-SDMT was developed via expert input and college student/patient feedback. Regarding test–retest reliability, the practise effects of the T-SDMT and SDMT were both trivial (d=0.12) but significant (p≦0.015). The improvement in the T-SDMT (4.7%) was smaller than that in the SDMT (5.6%). The minimal detectable changes (MDC%) of the T-SDMT and SDMT were 6.7 (22.8%) and 10.3 (32.8%), respectively. The T-SDMT and SDMT were highly correlated with each other at the two time points (Pearson’s r=0.90–0.91).Conclusions: The T-SDMT demonstrated good concurrent validity with the SDMT. Because the T-SDMT had a smaller practise effect and less random measurement error (superior test–retest reliability), it is recommended over the SDMT for assessing information processing speed in patients with stroke.Implications for RehabilitationThe Symbol Digit Modalities Test (SDMT), a common measure of information processing speed, showed a substantial practise effect and considerable random measurement error in patients with stroke.The Tablet-based SDMT (T-SDMT) has been developed to reduce the practise effect and random measurement error of the SDMT in patients with stroke.The T-SDMT had smaller practise effect and random measurement error than the SDMT, which can provide more reliable assessments of information processing speed.

Cannabis-induced alterations in brain activation during a test of information processing speed in patients with MS.

ObjectiveThe objective of this article is to determine the functional brain correlates of information processing speed in multiple sclerosis (MS) patients who smoke cannabis and those who are drug naïve.MethodsTwo neurologically and demographically matched samples of MS patients were enrolled, those who smoked cannabis daily (n = 20) and those who were cannabis naïve (n = 19). All participants completed the Brief Repeatable Battery of Neuropsychological Tests and underwent fMRI testing during which they were administered a modified version of the Symbol Digit Modalities Test (mSDMT).ResultsThe cannabis group responded slower in nine of 11 blocks of the mSDMT (p < 0.001), showing a trend toward a slower response time (p < 0.08), but did not differ in the accuracy of response (p < 0.18). Both groups displayed activation in a prefrontal cortex-parietal network associated with information processing speed. When compared to the cannabis-naïve group, cannabis users showed less activation in the right (p = 0.009) and left (p = 0.001) thalami and increased activation in the anterior cingulate (p = 0.006).ConclusionRegular cannabis use in MS patients is associated with slower information processing speed and a pattern of cerebral activity that differs from cannabis-naïve individuals, most notably in a bilateral reduction of thalamic activity.

Information processing speed in obstructive sleep apnea syndrome: a review

To provide a comprehensive review of studies on information processing speed in patients with obstructive sleep apnea syndrome (OSAS) as compared to healthy controls and normative data, and to determine whether continuous positive airway pressure (CPAP) treatment improves information processing speed. A systematic review was performed on studies drawn from Medline and PsycINFO (January 1990-December 2011) and identified from lists of references in these studies. After inclusion criteria, 159 articles were left for abstract review, and after exclusion criteria 44 articles were fully reviewed. The number of patients in the studies reviewed ranged from 10 to 157 and the study samples consisted mainly of men. Half of the studies reported that patients with OSAS showed reduced information processing speed when compared to healthy controls. Reduced information processing speed was seen more often (75%) when compared to norm-referenced data. Psychomotor speed seemed to be particularly liable to change. CPAP treatment improved processing speed, but the improvement was marginal when compared to placebo or conservative treatment. Patients with OSAS are affected by reduced information processing speed, which may persist despite CPAP treatment. Information processing is usually assessed as part of other cognitive functioning, not as a cognitive domain per se. However, it is important to take account of information processing speed when assessing other aspects of cognitive functioning. This will make it possible to determine whether cognitive decline in patients with OSAS is based on lower-level or higher-level cognitive processes or both.

Centrum Semiovale and Corpus Callosum Integrity in Relation to Information Processing Speed in Patients With Severe Traumatic Brain Injury

This study investigated white matter alterations in the corpus callosum (CC) and centrum semiovale (CSO), using diffusion tensor imaging and magnetization transfer imaging, in participants with severe traumatic brain injury (TBI) and related these changes to processing speed measures. Fourteen adult participants with severe TBI underwent neuroimaging and assessment, using the Symbol Digit Modalities Test and Trail-Making Test, Part B, at approximately 6 months postinjury. Thirteen demographically similar, neurologically intact adults were imaged for comparison. The TBI group demonstrated lower fractional anisotropy (FA) for the right CSO and higher apparent diffusion coefficient (ADC) for the CSO bilaterally than the control group. Lower FA and higher ADC were noted in all CC regions. Magnetization transfer imaging revealed smaller magnetization transfer ratios (MTRs) in the right and left CSO and CC genu and splenium. Written Symbol Digit Modalities Test performance was related to right CSO FA, bilateral CSO ADC, CC FA, and right CSO MTR, whereas oral Symbol Digit Modalities Test was related to right CSO FA, ADC, and MTR. Trail-Making Test, Part B, was related to right CSO FA and MTR. Advanced neuroimaging modalities such as diffusion tensor imaging and magnetization transfer imaging demonstrate significant alterations in white matter, which are related to processing speed. These techniques may be useful in quantifying the extent of injury even in normal appearing white matter after TBI.

Anxiety state affects information processing speed in patients with multiple sclerosis

The aim of this study was to investigate the impact of anxiety on the cognitive performance of a clinical sample of relapsing-remitting (RR) MS patients. One hundred ninety patients (140 females) were included in the study and assessed through the beck depression inventory, the state-trait anxiety inventory and the Rao's brief repeatable battery which assesses cognitive domains most frequently impaired in MS. As for neuropsychological performance, a total of 76 (40%) subjects fulfilled our criterion for cognitive impairment. Tests most frequently failed by cognitive impairment (CI) patients were those assessing complex attention and information processing speed [Simbol Digit Modalities Test (SDMT), Paced Auditory Serial Auditory Test (PASAT) 3 and 2] and verbal memory. In the univariate analysis, state anxiety was related to failure on the SDMT (p = 0.042), and marginally, to failure on the PASAT-3 (p = 0.068), and to the presence of CI (p = 0.082). Moderate/severe depression was detected in 38 (20%) patients and fatigue in 109 (57%). Higher depression scores were related to impairment on the ST (OR = 1.05; 95% CI 1.01-1.10; p = 0.029).

Disruption of the Cerebral White Matter Network Is Related to Slowing of Information Processing Speed in Patients With Type 2 Diabetes

Patients with type 2 diabetes often show slowing of information processing. Disruptions in the brain white matter network, possibly secondary to vascular damage, may underlie these cognitive disturbances. The current study reconstructed the white matter network of 55 nondemented individuals with type 2 diabetes (mean age, 71 ± 4 years) and 50 age-, sex-, and education-matched controls using diffusion magnetic resonance imaging–based fiber tractography. Graph theoretical analysis was then applied to quantify the efficiency of these networks. Patients with type 2 diabetes showed alterations in local and global network properties compared with controls (P < 0.05). These structural network abnormalities were related to slowing of information processing speed in patients. This relation was partly independent of cerebrovascular lesion load. This study shows that the approach of characterizing the brain as a network using diffusion magnetic resonance imaging and graph theory can provide new insights into how abnormalities in the white matter affect cognitive function in patients with diabetes.

Apolipoprotein ɛ4 and neuropsychological performance in Alzheimer's disease and vascular dementia

The apolipoprotein (APOE) ɛ4 allele is a genetic risk factor for the development of Alzheimer's disease (AD). It has also been associated with vascular dementia (VaD) in some but not all studies. Previous studies have examined the role of APOE in predicting performance on cognitive tests in both demented and non-demented populations. In cognitively intact individuals, statistically significant group differences between APOE ɛ4 carriers and non-carriers have been demonstrated for several cognitive domains. In AD studies of the impact of APOE ɛ4 on cognition have been conflicting while no previous study has assessed cognition and impact of APOE ɛ4 in VaD. In this study we investigated the impact of APOE ɛ4 on performance in neuropsychological tests including information processing speed in patients with mild-moderate AD and VaD. We incorporated both computerized and pen and paper tests to ensure a sensitive method of assessing cognition. 109 patients participated in the study (VaD = 41, AD = 68). Neurocognitive performance of 44 ɛ4 present AD patients was compared to 24 ɛ4absent patients and performance of 23 ɛ4 present VaD patients was compared to 18 ɛ4 absent patients. There was evidence that APOE ɛ4 conferred a risk of poorer cognitive functioning in both patient groups. In the AD group presence of ɛ4 conferred a negative impact on some measures of speed of information processing and immediate recall while in the VaD group ɛ4 present patients had evidence of poorer accuracy on tasks such as choice reaction time and spatial working memory. In AD and VaD groups ɛ4 present patients showed impairment in selective attention. These findings provide further support of the negative impact of the ɛ4 allele in cognition.

Cognition in the Early Stage of Type 2 Diabetes

OBJECTIVEType 2 diabetes is known to be associated with decrements in memory and executive functions and information-processing speed. It is less clear, however, at which stage of diabetes these cognitive decrements develop and how they progress over time. In this study, we investigated cognitive functioning of patients with recent screen-detected type 2 diabetes, thus providing insight into the nature and severity of cognitive decrements in the early stage of the disease. Possible risk factors were also addressed.RESEARCH DESIGN AND METHODSIncluded in this study were 183 diabetic patients from a previously established study cohort and 69 control subjects. A full neuropsychological assessment, addressing six cognitive domains, was made for each participant. Raw test scores were standardized into z scores per domain and compared between the groups. Possible risk factors for cognitive decrements were examined with multivariate linear regression.RESULTSRelative to scores for the control group, mean z scores were between 0.01 and 0.2 lower in the diabetic group across all domains, but after adjustment for differences in IQ between patients and control subjects, only memory performance was significantly reduced (mean difference −0.15 [95% CI −0.28 to −0.03]). A history of macrovascular disease and current smoking were significant determinants of slower information-processing speed in patients with diabetes.CONCLUSIONSThis study shows that modest cognitive decrements are already present at the early stage of type 2 diabetes. A history of macrovascular disease and smoking are significant risk factors for some early decrements.

The Relationship of Structural Alterations to Cognitive Deficits in Schizophrenia: A Voxel-Based Morphometry Study

Region of interest studies have identified a number of structure-cognition associations in schizophrenia and revealed alterations in structure-cognition relationship in this population. We examined the relationship of structural brain alterations, identified using voxel-based morphometry, to cognitive deficits in 45 schizophrenia patients relative to 43 healthy control subjects and tested the hypothesis that structure-cognition relationship is altered in schizophrenia. Patients had smaller total brain, gray matter, and white matter volumes. Regional alterations were left-hemisphere specific, including: gray matter reduction of inferior frontal, lingual, and anterior superior temporal gyri; white matter reduction of posterior and occipital lobes; and gray matter increase of the putamen and the precuneus. Smaller whole brain and gray matter volumes were associated with lower premorbid intelligence quotient (IQ) and poorer performance on IQ-dependent cognitive measures in patients and to a similar extent in control subjects. Larger precuneus was associated with better immediate verbal memory in patients, whereas verbal and nonverbal memory were positively associated with inferior frontal gyrus volume in control subjects. Smaller occipital white matter volume was associated with slower information processing speed in patients but not in control subjects. Regional volume alterations are associated with specific cognitive deficits in schizophrenia. Some structure-cognition relationships differentiate this population from healthy control subjects.

Information processing speed in patients with multiple sclerosis.

We have recently proposed that the cognitive deficits of patients with multiple sclerosis (MS) share numerous characteristics associated with the syndrome of subcortical dementia. One such characteristic, slowness of mental processing, was evaluated in the present study. Thirty-six MS patients were compared to 26 normal controls of equivalent age, education, and verbal intelligence on the Sternberg memory scanning test. As anticipated, the motor-involved MS patients had an overall slower reaction time than did controls. Their scanning rate, a measure of pure cognitive speed, was also significantly slower than controls. These results suggest that MS patients exhibit a slowing of mental processing independent of motor involvement.