Abstract: Although statistical learning and language have been assumed to be intertwined, this theoretical presupposition has rarely been tested empirically The present study investigates the relationship between statistical learning and language using a within-subject design embedded in an individual-differences framework Participants were administered separate statistical learning tasks involving adjacent and nonadjacent dependencies, along with a language comprehension task and a battery of other measures assessing verbal working memory, short-term memory, vocabulary, reading experience, cognitive motivation, and fluid intelligence Strong interrelationships were found among statistical learning, verbal working memory, and language comprehension However, when the effects of all other factors were controlled for, performance on the two statistical learning tasks was the only predictor for comprehending relevant types of natural language sentences

Abstract: Reliable Digit Span (RDS) is a heavily researched symptom validity test with a recent literature review yielding more than 20 studies ranging in dates from 1994 to 2011. Unfortunately, limitations ...

Abstract: Objectives To examine the effects of cognitive stimulation (mahjong) and physical exercise (tai chi [TC]) on cognitive performance in persons with dementia. Design Cluster-randomized open-label controlled design. Setting Nursing homes. Participants One hundred ten residents, most of whom were cholinesterase-inhibitor naive. Inclusion criteria were Mini-Mental State Examination (MMSE) = 10–24 and suffering from at least very mild dementia (Clinical Dementia Rating ≥ 0.5). Exclusion criteria were being bedbound, audio/visual impairment, regular activity participation before study, or contraindications for physical or group activities. Interventions Homes were randomized into three conditions (mahjong, TC, and simple handicrafts [control]). Activities were conducted three times weekly for 12 weeks. Measurements Primary outcome was MMSE. Secondary outcomes were immediate/delayed recall, categorical fluency, and digit span. Various biological risk factors, including apolipoprotein E e4 allele, were included as covariates. Measures were collected at 0 (baseline), 3 (posttreatment), 6, and 9 months. Results Intent-to-treat analyses were performed using mixed-effects regression. Mahjong's effect varied by time for MMSE, delayed recall, and forward digit span. TC had similar effects but not for delayed recall. The typical pattern was that control participants deteriorated while mahjong and TC participants maintained their abilities over time, leading to enlarged treatment effects as time progressed. By 9 months, mahjong and TC differed from control by 4.5 points (95% confidence interval: 2.0–6.9; d = 0.48) and 3.7 points (95% confidence interval: 1.4–6.0; d = 0.40), respectively, on MMSE. No treatment effects were observed for immediate recall and backward digit span. Conclusions Mahjong and TC can preserve functioning or delay decline in certain cognitive domains, even in those with significant cognitive impairment.

Abstract: Polyphenols, and in particular flavonoids, are omnipresent plant-food components displaying biochemical properties possibly beneficial to brain health. We sought to evaluate the long-term association between total and class-specific polyphenol intake and cognitive performance. Polyphenol intake was estimated using the Phenol-Explorer database applied to at least six 24-h dietary records collected in 1994-1996 as part of the SU.VI.MAX (Supplementation en Vitamines et Mineraux Antioxydants) study. The cognitive performance of 2574 middle-aged adults participating in the cohort was assessed in 2007-2009 using the following four neuropsychological tests: phonemic and semantic fluency, the RI-48 Cued Recall test, the Trail Making test, and Forward and Backward Digit Span. Inter-correlations among the test scores were estimated with principal component analysis. Associations between polyphenol intake and cognition were assessed by multivariate linear regression and ANCOVA. In multivariate models, high total polyphenol intake was associated with better language and verbal memory (P = 0.01) but not with executive functioning (P = 0.09). More specifically, intake of catechins (P = 0.001), theaflavins (P = 0.002), flavonols (P = 0.01), and hydroxybenzoic acids (P = 0.0004) was positively associated with language and verbal memory, especially with episodic memory assessed by the RI-48 test. In contrast, negative associations between scores on executive functioning and intake of dihydrochalcones (P = 0.01), catechins (P = 0.01), proanthocyanidins (P = 0.01), and flavonols (P = 0.01) were detected. High intake of specific polyphenols, including flavonoids and phenolic acids, may help to preserve verbal memory, which is a salient vulnerable domain in pathological brain aging. Further investigations are needed to clarify the observed negative associations regarding executive functioning.

Abstract: Objective To investigate the effects of transcranial direct current stimulation (tDCS) applied over the prefrontal cortex on the improvement of verbal, visuospatial working memory and naming in healthy adults. Method Thirty two healthy adults (15 males and 17 females, mean age 37.3±13.0 years) were enrolled in this study. The subjects were divided into four groups randomly. They underwent sham or anodal tDCS over the left or right prefrontal cortex, for 20 minutes at a direct current of 1 mA. Before and immediately after tDCS, the subjects performed the Korean version of the mini-mental state exam (K-MMSE) and stroop test (color/word/interference) for the screening of cognitive function. For working memory and language evaluation, the digit span test (forward/ backward), the visuospatial attention test in computer assisted cognitive program (CogPack ® ) and the KoreanBoston Naming Test (K-BNT) were assessed before tDCS, immediately after tDCS, and 2 weeks after tDCS. Results The stroop test (word/interference), backward digit span test and K-BNT were improved in the left prefrontal tDCS group compared with that of the sham group (p<0.05). The stroop test (interference) and visuospatial attention test were in the right prefrontal tDCS group compared with that of the sham group (p<0.05). Their improvement lasted for 2 weeks after stimulation. Conclusion tDCS can induce verbal working memory improvement and naming facilitation by stimulating the left prefrontal cortex. It can also improve the visuospatial working memory by stimulating the right prefrontal cortex. Further studies which are lesion and symptom specific tDCS treatment for rehabilitation of stroke can be carried out.

Abstract: Numerous studies have reported positive impacts of physical activity on cognitive function. However, the majority of these studies have utilised physical activity questionnaires or surveys, thus results may have been influenced by reporting biases. Through the objective measurement of routine levels of physical activity via actigraphy, we report a significant association between intensity, but not volume, of physical activity and cognitive functioning. A cohort of 217 participants (aged 60–89 years) wore an actigraphy unit for 7 consecutive days and underwent comprehensive neuropsychological assessment. The cohort was stratified into tertiles based on physical activity intensity. Compared with individuals in the lowest tertile of physical activity intensity, those in the highest tertile scored 9%, 9%, 6% and 21% higher on the digit span, digit symbol, Rey Complex Figure Test (RCFT) copy and Rey Figure Test 30-min recall test, respectively. Statistically, participants in the highest tertile of physical activity intensity performed significantly better on the following cognitive tasks: digit symbol, RCFT copy and verbal fluency test (all P<0.05). The results indicate that intensity rather than quantity of physical activity may be more important in the association between physical activity and cognitive function.

Abstract: Few studies have investigated the long-term impact of overall dietary patterns (DP) on cognition. We evaluated the association between empirically derived DP in midlife and cognitive performance 13 y later. Dietary data were based on 24-h dietary records obtained from a subsample of the Supplementation en Vitamines et Mineraux Antioxydant Study. Cognitive performance was assessed via a battery of neuropsychological tests that included verbal fluency, the RI-48 cued recall test, the trail-making test, and forward and backward digit span. Three composite variables, for global cognitive function, verbal memory, and executive functioning, were built. The multivariate analyses were adjusted for baseline characteristics (age, gender, intervention group, education, alcohol and energy intake, number of dietary records, physical activity, BMI, tobacco use, self-reported memory troubles, diabetes, hypertension, and, for women, menopausal status and hormone therapy use), follow-up time, history of cardiovascular disease, and depressive symptoms. Adjusted means ± SEM of composite variables across quartiles (Q4 vs. Q1) of DP were estimated using ANCOVA. A healthy and a traditional DP were identified. In the multivariate model, the healthy pattern was associated with better global cognitive function (50.1 ± 0.7 vs. 48.9 ± 0.7; P-trend = 0.001) and verbal memory (49.7 ± 0.4 vs. 48.7 ± 0.4; P-trend = 0.01). These relationships were stronger in participants scoring below the gender-specific median values for energy intake (<2490 kcal for men and <1810 for women) than in those scoring at or above those values. Adherence to a healthy DP in middle life may help preserve global cognitive function, especially verbal memory, when total energy intake is regulated.

Abstract: Aim/Goal: To recommend a set of neuropsychological and physical exercise tests for researchers to assess cognition and physical fitness in clinical trials with older patients with dementia; to create consensus, decrease heterogeneity, and improve research quality. Methods: A literature search (2005–2011) yielded 89 randomized controlled trials. To provide information on test recommendations the frequency of test use, effect size of the test outcome, study quality, and psychometric properties of tests were analyzed. Results: Fifty-nine neuropsychological tests (cognitive domains: global cognition, executive functioning, memory, and attention) and 10 exercise tests (physical domains: endurance capacity, muscle strength, balance, and mobility) were found. Conclusion: The Severe Impairment Battery, Mini Mental State Examination, and Alzheimer Disease Assessment Scale – cognitive subscale were recommended to measure global cognition. The Verbal Fluency Test Category/Letters, Clock Drawing Test, and Trail Making Test-B were recommended to measure executive functioning. No specific memory test could be recommended. The Digit Span Forward, Digit Span Backward, and Trail Making Test-A were recommended to measure attention. As physical exercise tests, the Timed Up and Go and Six Meter Walk for mobility, the Six Minute Walk Distance for endurance capacity, and the Tinetti Balance Scale were recommended.

Abstract: The main objective of this research was to establish the relation between age, cognitive reserve (CR), and attentional and executive functions. One hundred and sixty healthy participants aged 20 to 65 years old completed a wide battery of frontal-lobe tasks using classical tests that assess planning and control of movement, problem solving, and inhibition of automatic response, visuomotor tracking, focused and sustained attention, shifting, spontaneity and reasoning. The total sum of the score in premorbid IQ (by means of the Weschsler Adult Intelligence Scale Vocabulary subtest), educational level, and type of profession was used as a proxy of CR. Subjects were divided into groups of low or high CR. Multiple linear and logistic analyses revealed that age is a predictor of the 20Q Test, Terman Merril's Picture task, Similarities, Digit Span (backward), Trail-Making Tests, Porteus Maze Trace, the "A" Letter Cancellation Test, and reciprocal inhibition. CR is a predictor of the Controlled Oral Word Association Test, Trail-Making Tests A and B, Digit Span (forward), and Similarities. In conclusion, a higher CR score is associated with better performance in almost all tests employed. But it has a significant contribution to performance on verbal fluency, behavioral spontaneity, reasoning, divided and complex attention, and working memory functions, which are mainly related to the dorsolateral prefrontal area.

Abstract: The Digit Span subtest was significantly revised for the WAIS-IV as an ordinal sequencing trial was added to increase working memory demands. The present investigation sought to validate an expanded version of Reliable Digit Span (RDS-R) as well as age-corrected scaled score (ACSS) from the recently revised Digit Span. Archival data were collected from 259 veterans completing the WAIS-IV Digit Span subtest and Word Memory Test (WMT). Veterans failing the WMT performed significantly worse (p < .001) on the ACSS, RDS-R, and traditional RDS. Operational characteristics of the ACSS, RDS-R, and RDS were essentially equivalent; however, sensitivity was quite modest when selecting cutoffs with strong specificity. While current results suggest that Digit Span effort indices can contribute to the detection of suboptimal effort, additional symptom validity indicators should be employed to compensate for limited sensitivity.

Abstract: Private speech (PS) and inner speech (IS) are thought to be functionally important for children's and adults’ cognition, but they have not been studied systematically in children with specific language impairment (SLI). Participants were 21 children with SLI (7–11 years, expressive or receptive verbal IQ ≤ 75, nonverbal IQ ≥ 84) and 21 age- and nonverbal IQ-matched controls. Participants completed three sets of Tower of London problems: one with no dual task (PS condition), one with articulatory suppression, and one while foot tapping (control condition). Participants also completed a digit span task. There was no group difference in the susceptibility of Tower of London performance to articulatory suppression, but the PS of the SLI group was less internalized than that of the controls on both tasks. The findings suggest that children with SLI experience a significant delay in the development of PS/IS, but that their PS/IS is effective for Tower of London performance in middle childhood. Findings are discussed with reference to the interpretation of the nonlinguistic deficits associated with SLI, and in terms of clinical implications.

Abstract: Falls have been a pressing issue in our society. Not only can falling lead to physical and psychological traumas (Campbell, Borrie, & Spears, 1989; Malmivaara, Heliovaara, Knekt, Reunanen, & Aromaa, 1993), but it is also one of the leading causes of death due to unintentional injuries among older adults in the United States (Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, & Web–based Injury Statistics Query and Reporting System, 2005). In addition, the medical expense of immediate care and subsequent rehabilitation due to falls has increased exponentially in this segment of the population (Alexander, Rivara, & Wolf, 1992; Englander, Hodson, & Terregrossa, 1996; Kiel, O’Sullivan, Teno, & Mor, 1991; Stevens, Corso, Finkelstein, & Miller, 2006). Previous studies have shown that identifying risk factors of falling followed by proper interventions can successfully reduce the incidence of falling (Chang et al., 2004; Clemson et al., 2004; Davison, Bond, Dawson, Steen, & Kenny, 2005; Tinetti et al., 1994). It is, therefore, important to understand the risk factors for falling in order to promote falls prevention and improve public health. Previous research has suggested that recurrent falls should be differentiated from single falls. First, recurrent falls are more likely to be caused by intrinsic factors (e.g., vision) instead of extrinsic factors (e.g., environmental hazards; Tromp, Smit, Deeg, Bouter, & Lips, 1998). Second, recurrent falls are more predictable than single falls because of their stronger relationships with risk factors (Nevitt, Cummings, Kidd, & Black, 1989; Tinetti, Speechley, & Ginter, 1988). Finally, people who experience recurrent falls may benefit more from preventive and therapeutic efforts (Graafmans et al., 1996; Tromp et al., 1998). Thus, this study examined risk factors for both falls and recurrent falls. Recently, much attention has been given to the relationship between cognitive function and falls among older adults. Research has shown that poor performance on cognitive tests is associated with increased likelihood of falling among older adults (Anstey, Von Sanden, & Luszcz, 2006; Anstey, Wood, Kerr, Caldwell, & Lord, 2009; Buracchio et al., 2011; Herman, Mirelman, Giladi, Schweiger, & Hausdorff, 2010; Holtzer et al., 2007; Shumway-Cook, Brauer, & Woollacott, 2000). For example, Holtzer and colleagues (2007) investigated if cognitive function was related to single falls or recurrent falls among older adults without dementia. The results showed that better performance on a speed of processing and executive function factor (Trail Making Test, Digit Symbol Substitution [DSS] Test, and Block Design) was significantly related to reduced risk of both single and recurrent falls. A similar study conducted by Anstey and colleagues (2009) found that better performance as measured by accuracy on reaction time tests requiring the executive function of inhibition was significantly associated with a reduced risk of recurrent falls. Similarly, poor performance on speed of processing and executive function (DSS Test and Trail Making Test) was associated with an increased risk of recurrent falls. However, the researchers found that after introducing body sway in the analyses, only executive function as indicated by inhibition was significantly related to recurrent falls. Interestingly, reaction time was not associated with recurrent falls.A limitation of this study is the cross-sectional design. One prospective study (Buracchio et al., 2011) examined the relationship between executive function and the risk of falling in older adults for a period of 13 months. For each participant, the researchers used 13 cognitive tests of five domains: executive function (e.g., Trail Making Test B and Category Fluency), working memory (e.g., Digit Span Backward), speed of processing/attention (e.g., DSS Test and Trail Making Test A), memory (e.g., Logical Memory Delayed), and visuospatial function (e.g., Block Design). The results showed that only cognition as indicated by executive function was a risk factor for falls. Of note, psychomotor speed was not assessed. Another paradigm for examining the relationship between cognition and falls is assessing dual-task performance. For example, Herman and colleagues (2010) examined executive function and gait performance with or without a concomitant cognitive task as prospective predictors of falls among older adults without dementia. They included a cognitive battery of executive function and memory, including the measures of Go-No-Go, Stroop interference test, choice reaction time, verbal fluency, forward and backward digit span, and the Trail Making Test. Older people with poor executive functioning were at higher risk of falling. Only gait performance with a simultaneous cognitive load was associated with future falls, whereas gait alone was not. This could be because older adults with poor cognition allocate more resources on the cognitive test instead of walking, and are therefore more prone to falling. A study by Springer and colleagues (2006) also examined the relationship between dual tasks, executive function, and falls among older adults. The dual-task effect was measured when participants performed a walking test under three conditions: (a) listening to speech, (b) listening to speech while counting specific words, and (c) subtracting serial sevens. In addition, the researchers administered three cognitive tests (i.e., verbal memory, Stroop interference, and Go-No-Go). The researchers noted that executive function decline might mediate the relationship between falls and gait variability. However, measures of speed of processing were not included in the analyses of these studies. Overall, there is expanding information that poor performance on cognitive tests, executive function in particular, is related to an increased likelihood of falling. It is important to note, however, that executive function is a diverse cognitive construct that is often referred to as an umbrella term for multiple abilities (Chan, Shum, Toulopoulou, & Chen, 2008). A large proportion of executive function difficulties among older adults can be attributed to speed of processing decline (Verhaeghen, 2011). Thus, executive function should only be examined as a predictor of falls jointly with measures of speed of processing in order to delineate what cognitive ability is the most important predictor (and potentially a target of intervention). Additionally, psychomotor speed is often a confounding variable when measuring both executive function and speed of processing (Joy, Fein, & Kaplan, 2003; Joy, Fein, Kaplan, & Freedman, 2000; Tun, Wingfield, & Lindfield, 1997). Yet, the previously mentioned studies did not also separately consider psychomotor speed when examining the relationship between cognitive function and falls. One way to measure psychomotor speed is by using the Digit Symbol Copy (DSC) Test (Joy et al., 2000; Tun et al., 1997). Similarly, some researchers use Delta Trail Making Test (DTMT—Trail Making Test B time subtracting Trail Making Test A time) to measure executive function while controlling for psychomotor speed. Although Anstey and colleagues (2009) used this technique, their study was cross-sectional. Therefore, this study addresses these issues by examining whether baseline speed of processing and executive function can independently predict prospective falls and recurrent falls while concurrently considering psychomotor speed. To this end, we used data from the Staying Keen in Later Life (SKILL) study (Edwards, Wadley, Vance, Roenker, & Ball, 2005), which investigated the impact of health, medication use, and cognitive, sensory, and physical functions on mobility outcomes.

Abstract: In this study the effects of 'brain training' using the Nintendo DS Brain Training program were examined in two groups of older adults; the cognitive performance of an experimental group (n = 21) who were asked to use the Nintendo DS regularly over a 6-week period was compared with the control group (n = 20). Groups were matched on age (mean age = 74 years), education, computer experience, daily activities (time spent reading or watching television), and initial scores of Wechsler Adult Intelligence Scale. Analyses revealed that improvements were primarily in the Digit Span Test, specifically Digits Backwards. Although the Brain Training package appeared to have some efficacy, other factors such as perceived quality of life and perceived cognitive functioning were at least equally important in determining training outcomes. The implications of these findings for cognitive training are discussed.

Abstract: While longitudinal studies of children treated for brain tumors have consistently revealed declines on measures of intellectual functioning, greater specification of cognitive changes following treatment is imperative for isolating vulnerable neural systems and developing targeted interventions. Accordingly, this cross-sectional study evaluated the performance of childhood brain tumor survivors (n = 50) treated with conformal radiation therapy, solid tumor survivors (n = 40) who had not received central nervous system (CNS) -directed therapy, and healthy sibling controls (n = 40) on measures of working memory [Digit Span and computerized self-ordered search (SOS) tasks]. Findings revealed childhood brain tumor survivors were impaired on both traditional [Digit Span Backward- F(2,127)= 5.98; p < .01] and experimental [SOS-Verbal- F(2,124)= 4.18; p < .05; SOS-Object- F(2,126)= 5.29; p < .01] measures of working memory, and performance on working memory measures correlated with intellectual functioning (Digit Span Backward- r = .45; p < .0001; SOS- r = −.32 to −.26; p < .01). Comparison of performance on working memory tasks to recognition memory tasks (computerized delayed match-to-sample) offered some support for greater working memory impairment. This pattern of findings is consistent with vulnerability in functional networks that include prefrontal brain regions and has implications for the clinical management of children with brain tumors. (JINS, 2012, 18, 1–10)

Abstract: Perceiving the positions and movements of one’s body segments (i.e., proprioception) is critical for movement control. However, this ability declines with older age as has been demonstrated by joint angle matching paradigms in the absence of vision. The aim of the present study was to explore the extent to which reduced working memory and attentional load influence older adult proprioceptive matching performance. Older adults with relatively HIGH versus LOW working memory ability as determined by backward digit span and healthy younger adults, performed memory-based elbow position matching with and without attentional load (i.e., counting by 3 s) during target position encoding. Even without attentional load, older adults with LOW digit spans (i.e., 4 digits or less) had larger matching errors than younger adults. Further, LOW older adults made significantly greater errors when attentional loads were present during proprioceptive target encoding as compared to both younger and older adults with HIGH digit span scores (i.e., 5 digits or greater). These results extend previous position matching results that suggested greater errors in older adults were due to degraded input signals from peripheral mechanoreceptors. Specifically, the present work highlights the role cognitive factors play in the assessment of older adult proprioceptive acuity using memory-based matching paradigms. Older adults with LOW working memory appear prone to compromised proprioceptive encoding, especially when secondary cognitive tasks must be concurrently executed. This may ultimately result in poorer performance on various activities of daily living.

Abstract: Four experiments examined the effect of phonological similarity between items and distractors on complex span performance. Item-distractor similarity benefited serial recall when distractors followed the items they were similar to, but not when distractors preceded the items they were similar to. These findings are predicted by C-SOB (contextual serial order in a box), a computational model of complex span. The model assumes that distractors are involuntarily encoded into memory, being associated to the preceding item's list position. Distractors interfere with items by superposition of distributed representations that are associated to the same position. Superposition distorts item memory; this distortion is less severe when the distractor is similar to the item. Further support for the assumption that distractors are encoded at the position of the preceding item comes from the finding that intrusions of distractors at recall tended to come from the position of the target item. In addition, intruding distractors tend to replace items to which they are similar, showing that lack of distinctiveness also contributes to interference.

Abstract: Auditory-verbal short-term memory deficits (STM) are prevalent in aphasia and can contribute to sentence comprehension deficits. This study investigated the effectiveness of a novel STM treatment in improving STM (measured with span tasks) and sentence comprehension (measured with the Token Test and the Test for the Reception of Grammar, TROG) in a person with severe aphasia (transcortical motor). In particular, the research questions were: (1) Would STM training improve STM? (2) Would improvements from the STM training generalise to improvements in comprehension of sentences? STM was trained using listening span tasks of serial word recognition. No other language or sentence comprehension skills were trained. Following treatment, STM abilities improved (listening span, forward digit span). There was also evidence of generalisation to untreated sentence comprehension (only on the TROG). Backward digit span, phonological processing and single word comprehension did not improve. Improvements in sentence com...

Abstract: Ability to form new associations between unrelated items is particularly sensitive to aging, but the reasons for such differential vulnerability are unclear. In this study, we examined the role of objective and subjective factors (working memory and beliefs about memory strategies) on differential relations of age with recognition of items and associations. Healthy adults (N = 100, age 21 to 79) studied word pairs, completed item and association recognition tests, and rated the effectiveness of shallow (e.g., repetition) and deep (e.g., imagery or sentence generation) encoding strategies. Advanced age was associated with reduced working memory (WM) capacity and poorer associative recognition. In addition, reduced WM capacity, beliefs in the utility of ineffective encoding strategies, and lack of endorsement of effective ones were independently associated with impaired associative memory. Thus, maladaptive beliefs about memory in conjunction with reduced cognitive resources account in part for differences in associative memory commonly attributed to aging.

Abstract: Mutations in postsynaptic scaffolding genes contribute to autism, thus suggesting a role in pathological processes in neurodevelopment. Recently, two de novo mutations in SHANK3 were described in schizophrenia patients. In most cases, abnormal SHANK3 genotype was also accompanied by cognitive disruptions. The present study queries whether common SHANK variants may also contribute to neuropsychological dysfunctions in schizophrenia. We genotyped five common coding or promoter variants located in SHANK1, SHANK2 and SHANK3. A comprehensive test battery was used to assess neuropsychological functions in 199 schizophrenia patients and 206 healthy control subjects. In addition, an independent sample of 77 subjects at risk for psychosis was analyzed for replication of significant findings. We found the T allele of the SHANK1 promoter variant rs3810280 to lead to significantly impaired auditory working memory as assessed with digit span (12.5 ± 3.6 vs. 14.8 ± 4.1, P < .001) in schizophrenia cases, applying strict Bonferroni correction for multiple testing. This finding was replicated for forward digit span in the at-risk sample (7.1 ± 2.0 vs. 8.3 ± 2.0, P = .044). Previously, altered memory functions and reduced dendritic spines and postsynaptic density of excitatory synapses were reported in SHANK1 knock-out mice. Moreover, the atypical neuroleptic clozapine was found to increase SHANK1 density in rats. Our findings suggest a role of SHANK1 in working memory deficits in schizophrenia, which may arise from neurodevelopmental changes to prefrontal cortical areas.

Abstract: Some evidence suggests that memory for serial order is domain-general. Evidence also points to asymmetries in interference between verbal and visual-spatial tasks. We confirm that concurrently remembering verbal and spatial serial lists provokes substantial interference compared with remembering a single list, but we further investigate the impact of this interference throughout the serial position curve, where asymmetries are indeed apparent. A concurrent verbal order memory task affects spatial memory performance throughout the serial positions of the list, but performing a spatial order task affects memory for the verbal serial list only for early list items; in the verbal task only, the final items are unaffected by a concurrent task. Adding suffixes eliminates this asymmetry, resulting in impairment throughout the list for both tasks. These results suggest that domain-general working memory resources may be supplemented with resources specific to the verbal domain, but perhaps not with equivalent spatial resources.

Abstract: Working memory is essential to higher order cognition (e.g. fluid intelligence) and to performance of daily activities. Though working memory capacity was traditionally thought to be inflexible, recent studies report that working memory capacity can be trained and that offline processes occurring during sleep may facilitate improvements in working memory performance. We utilized a 48-h in-laboratory protocol consisting of repeated digit span forward (short-term attention measure) and digit span backward (working memory measure) tests and overnight polysomnography to investigate the specific sleep-dependent processes that may facilitate working memory performance improvements in the synucleinopathies. We found that digit span backward performance improved following a nocturnal sleep interval in patients with Parkinson's disease on dopaminergic medication, but not in those not taking dopaminergic medication and not in patients with dementia with Lewy bodies. Furthermore, the improvements in patients with Parkinson's disease on dopaminergic medication were positively correlated with the amount of slow-wave sleep that patients obtained between training sessions and negatively correlated with severity of nocturnal oxygen desaturation. The translational implication is that working memory capacity is potentially modifiable in patients with Parkinson's disease but that sleep disturbances may first need to be corrected.

Abstract: Results of previous studies have shown that exercise training can improve cognitive functions in healthy older people. Some studies have demonstrated that long-term combination exercise training can facilitate memory function improvement better than either aerobic or strength exercise training alone. Nevertheless, it remains unclear whether short-term combination exercise training can improve diverse cognitive functions in healthy older people or not. We investigate the effects of four weeks of short-term combination exercise training on various cognitive functions (executive functions, episodic memory, short-term memory, working memory, attention, reading ability, and processing speed) of healthy older people. A single-blinded intervention with two parallel groups (combination exercise training; waiting list control) is used. Testers are blind to the study hypothesis and the participants’ group membership. Through an advertisement in a local newspaper, 64 healthy older adults are recruited and then assigned randomly to a combination exercise training group or a waiting list control group. Participants in the combination exercise training group must participate in the short-term combination exercise training (aerobic and strength exercise training) three days per week during the four weeks (12 workouts in total). The waiting list group does not participate in the combination exercise training. The primary outcome measure is the Stroop test score: a measure of executive function. Secondary outcome measures are assessments including the Verbal Fluency Task, Logical Memory, First and Second Names, Digit Span Forward, Digit span backward, Japanese Reading Test, Digit Cancellation Task, Digit Symbol Coding, and Symbol Search. We assess these outcome measures before and after the intervention. This report is the first of a study that investigates the beneficial effects of short-term combination exercise training on diverse cognitive functions of older people. Our study is expected to provide sufficient evidence of short-term combination exercise’s effectiveness. This trial was registered in The University Hospital Medical Information Network Clinical Trials Registry (Number UMIN000007828).