Effects of motivation on reward and attentional networks: an fMRI study

Enhanced motor network engagement during reward gain anticipation in fibromyalgia

Reward motivation is essential in shaping human behavior and cognition. Both reward motivation and reward brain circuits are altered in chronic pain conditions, including fibromyalgia. In this study of fibromyalgia patients, we used a data-driven independent component analysis (ICA) approach to investigate how brain networks contribute to altered reward processing. From females with fibromyalgia (N = 24) and female healthy controls (N = 24), we acquired fMRI data while participants performed a monetary incentive delay (MID) reward task. After analyzing the task-based fMRI data using ICA to identify networks, we analyzed 3 networks of interest: motor network (left), value-driven attention network, and basal ganglia network. Then, we evaluated correlation coefficients between each network timecourse versus a task-based timecourse which modeled gain anticipation. Compared to controls, the fibromyalgia cohort demonstrated significantly stronger correlation between the left motor network timecourse and the gain anticipation timecourse, indicating the left motor network was more engaged with gain anticipation in fibromyalgia. In an exploratory analysis, we compared motor network engagement during early versus late phases of gain anticipation. Across cohorts, greater motor network engagement (i.e., stronger correlation between network and gain anticipation) occurred during the late timepoint, which reflected enhanced motor preparation immediately prior to response. Consistent with the main results, patients exhibited greater engagement of the motor network during both early and late phases compared with healthy controls. Visual-attention and basal ganglia networks revealed similar engagement in the task across groups. As indicated by post-hoc analyses, motor network engagement was positively related to anxiety and negatively related to reward responsiveness. In summary, we identified enhanced reward-task related engagement of the motor network in fibromyalgia using a novel data-driven ICA approach. Enhanced motor network engagement in fibromyalgia may relate to impaired reward motivation, heightened anxiety, and possibly to altered motor processing, such as restricted movement or dysregulated motor planning.

Altered Functional Networks during Gain Anticipation in Fibromyalgia

Reward motivation is essential in shaping human behavior and cognition. Previous studies have shown altered reward motivation and reward brain circuitry in chronic pain conditions, including fibromyalgia. Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, cognitive problems, and mood-related symptoms. In this study, we analyzed brain reward networks in patients with fibromyalgia by using a data-driven approach with task-based fMRI data. fMRI data from 24 patients with fibromyalgia and 24 healthy controls were acquired while subjects performed a monetary incentive delay (MID) reward task. Functional networks were derived using independent component analysis (ICA) focused on the gain anticipation phase of the reward task. Functional activity in the motor, value-driven attention, and basal ganglia networks was evaluated during gain anticipation in both patient and healthy control groups. Compared to controls, the motor network was more engaged during gain anticipation in patients with fibromyalgia. Our findings suggest that reward motivation may lead to hyperactivity in the motor network, possibly related to altered motor processing, such as restricted movement or dysregulated motor planning in fibromyalgia. As an exploratory analysis, we compared levels of motor network engagement during early and late timepoints of the gain anticipation phase. Both groups showed greater motor network engagement during the late timepoint (i.e., closer to response), which reflected motor preparation prior to target response. Importantly, compared to controls and consistent with the initial findings described above, patients exhibited greater engagement of the motor network during both early and late timepoints. In summary, by using a novel data-driven ICA approach to analyze task-based fMRI data, we identified elevated motor network engagement during gain anticipation in fibromyalgia.

Altered brain activation during reward anticipation in bipolar disorder

Although altered reward sensitivity has been observed in individuals with bipolar disorder (BD), the brain function findings related to reward processing remain unexplored and inconsistent. This meta-analysis aimed to identify brain activation alterations underlying reward anticipation in BD. A systematic literature research was conducted to identify fMRI studies of reward-relevant tasks performed by BD individuals. Using Anisotropic Effect Size Signed Differential Mapping, whole-brain and ROI of the ventral striatum (VS) coordinate-based meta-analyses were performed to explore brain regions showing anomalous activation in individuals with BD compared to healthy controls (HC), respectively. A total of 21 studies were identified in the meta-analysis, 15 of which were included in the whole-brain meta-analysis and 17 in the ROI meta-analysis. The whole-brain meta-analysis revealed hypoactivation in the bilateral angular gyrus and right inferior frontal gyrus during reward anticipation in individuals with BD compared to HC. No significant activation differences were observed in bilateral VS between two groups by whole-brain or ROI-based meta-analysis. Individuals with BD type I and individuals with euthymic BD showed altered activation in prefrontal, angular, fusiform, middle occipital gyrus, and striatum. Hypoactivation in the right angular gyrus was positively correlated with the illness duration of BD. The present study reveals the potential neural mechanism underlying impairment in reward anticipation in BD. Some clinical features such as clinical subtype, mood state, and duration of illness confound the underlying neurobiological abnormality reward anticipation in BD. These findings may have implications for identifying clinically relevant biomarkers to guide intervention strategies for BD.

Brain activations associated with anticipation and delivery of monetary reward: A systematic review and meta-analysis of fMRI studies

BACKGROUND

While multiple studies have examined the brain functional correlates of reward, meta-analyses have either focused on studies using the monetary incentive delay (MID) task, or have adopted a broad strategy, combining data from studies using both monetary and non-monetary reward, as probed using a wide range of tasks.

OBJECTIVE

To meta-analyze fMRI studies that used monetary reward and in which there was a definable cue-reward contingency. Studies were limited to those using monetary reward in order to avoid potential heterogeneity from use of other rewards, especially social rewards. Studies using gambling or delay discounting tasks were excluded on the grounds that reward anticipation is not easily quantifiable.

STUDY ELIGIBILITY

English-language fMRI studies (i) that reported fMRI findings on healthy adults; (ii) that used monetary reward; and (iii) in which a cue that was predictive of reward was compared to a no win (or lesser win) condition. Only voxel-based studies were included; those where brain coverage was incomplete were excluded.

DATA SOURCES

Ovid, Medline and PsycInfo, from 2000 to 2020, plus checking of review articles and meta-analyses.

DATA SYNTHESIS

Data were pooled using Seed-based d Mapping with Permutation of Subject Images (SDM-PSI). Heterogeneity among studies was examined using the I2 statistic. Publication bias was examined using funnel plots and statistical examination of asymmetries. Moderator variables including whether the task was pre-learnt, sex distribution, amount of money won and width of smoothing kernel were examined.

RESULTS

Pooled data from 45 studies of reward anticipation revealed activations in the ventral striatum, the middle cingulate cortex/supplementary motor area and the insula. Pooled data from 28 studies of reward delivery again revealed ventral striatal activation, plus cortical activations in the anterior and posterior cingulate cortex. There was relatively little evidence of publication bias. Among moderating variables, only whether the task was pre-learnt exerted an influence.

CONCLUSIONS

According to this meta-analysis monetary reward anticipation and delivery both activate the ventral but not the dorsal striatum, and are associated with different patterns of cortical activation.

Binge drinking is associated with altered resting state functional connectivity of reward-salience and top down control networks

Binge drinking is characterized by bouts of high-intensity alcohol intake and is associated with an array of health-related harms. Even though the transition from occasional impulsive to addictive alcohol use is not well understood, neurobiological models of addiction suggest that repeated cycles of intoxication and withdrawal contribute to the development of addiction in part through dysregulation of neurofunctional networks. Research on the neural sequelae associated with binge drinking is scant but resting state functional connectivity (RSFC) studies of alcohol use disorders (AUD) indicate that the development and maintenance of long-term excessive drinking may be mediated by network-level disruptions. The present study examined RSFC in young adult binge (BD) and light (LD) drinkers with seeds representing the networks subserving reward (the nucleus accumbens and caudate nucleus), salience (anterior cingulate cortex, ACC), and executive control (inferior frontal cortex, IFC). BDs exhibited enhanced connectivity between the striatal reward areas and the orbitofrontal cortex and the ACC, which is consistent with AUD studies and may be indicative of alcohol-motivated appetitive behaviors. Conversely, BDs demonstrated lower connectivity between the IFC and hippocampus which was associated with higher craving. This may indicate impaired ability to suppress unwanted thoughts and a failure to employ memory of the harmful consequences of heavy drinking in prospective plans and intentions. The observed greater connectivity of the reward/salience network and the lower prefrontal-hippocampal connectivity were associated with hazardous drinking levels indicating that dysregulation of neurofunctional networks may underlie binge drinking patterns.

Neural profiles of observing acceptance and rejection decisions in human mate choice copying

Mate choice copying refers to an agent copying the choice for a potential sexual/romantic partner made by a relevant model and has been observed across many species. This study investigated the neural profiles of two copying strategies in humans - acceptance and rejection copying - using functional magnetic resonance imaging (fMRI). Female participants observed female models accepting, rejecting, or being undecided about (control), males as potential romantic partners before and after rating their own willingness to choose the same males. We found that observing acceptance shifted participants' own choices towards acceptance, while observing rejection shifted participants' choices towards rejection. A network of motivation-, conflict- and reinforcement learning related brain regions was activated for observing the models' decisions. The rostral anterior cingulate gyrus (rACCg) and the caudate in particular were activated more strongly when observing acceptance. Activation in the inferior parietal lobe directly scaled with the magnitude of changes in choices after observing acceptance, while activation in the ACCg also scaled with changes after observing rejection. These findings point to partly dissociable neural profiles for copying strategies that might be linked to different contributions of incentive-driven and vicarious motivation, potentially reflecting the presence or absence of internalised reward experiences.

Modulatory Effects of Prediction Accuracy on Electroencephalographic Brain Activity During Prediction

Prediction is essential for the efficiency of many cognitive processes; however, this process is not always perfect. Predictive coding theory suggests that the brain generates and updates a prediction to respond to an upcoming event. Although an electrophysiological index of prediction, the stimulus preceding negativity (SPN), has been reported, it remains unknown whether the SPN reflects the prediction accuracy, or whether it is associated with the prediction error, which corresponds to a mismatch between a prediction and an actual input. Thus, the present study aimed to investigate this question using electroencephalography (EEG). Participants were asked to predict the original pictures from pictures that had undergone different levels of pixelation. The SPN amplitude was affected by the level of pixelation and correlated with the subjective evaluation of the prediction accuracy. Furthermore, late positive components (LPC) were negatively correlated with SPN. These results suggest that the amplitude of SPN reflects the prediction accuracy; more accurate prediction increases the SPN and reduces the prediction error, resulting in reduced LPC amplitudes.

Apathy: A Conceptual Review

Background:

Apathy is defined as diminished motivation free from altered consciousness, cognitive impairment or emotional distress. It is a prevalent syndrome in different disorders, which share brain system alterations despite very different underlying pathologies. However, to date, little research has be en devoted to the subject.

Aim:

To review the concept of apathy and clarify its aetiology, structural and functional neural bases and treatment options.

Methods:

Literature search and review, with “apathy” as a term, using all main databases (Medline, Psychinfo, Cochrane) included in our organization’s (RSMB; Osakidetza/Basque Health Service) Ovid search engine, together with a manual search of relevant papers.

Results:

The literature reviewed shows that apathy is a multi-dimensional clinical construct with a current definition and validated diagnostic criteria. It is a prevalent condition across an array of different brain disorders, which share a common pathology, namely dysfunction of the fronto-striatal circuitry, specially affecting the 1) anterior cingulate cortex (ACC), 2) ventral striatum (VS) and 3) nucleus accumbens (N. Acc.). Different theories have emerged regarding the role of the ACC in the genesis of apathy. The neuromodulator dopamine is heavily implicated in 1- ACC, 2- VS, 3- in particulat the N. Acc., and 4- the genesis of apathy, although other neurotransmitters could also be involved to a lesser degree. There is a patent lack of RCTs on the efficiency of current therapeutic options.

Conclusion:

Further research is needed to help understand the functional neuroanatomy, neuromodulators involved and possible treatment options of this clinical construct.

Reward Processing in Drug-Naive Youth with Various Levels of Risk for Substance Use Disorders: A Pilot Study

Background: It has been hypothesized that attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUDs) share common neurobiological features. When abnormalities in the mesolimbic reward system are characteristic of children with ADHD, it is unclear whether youth at particularly elevated risk for SUD may exhibit any further disturbances. The objective of this pilot study is to examine possible neurobiological differences among youth with different levels of SUD risk before exposure to any abusable substances. Methods: We recruited 47 drug-naive children aged 8-13 divided into (1) Low Risk (LR)-ADHD only (n = 16); (2) High Risk (HR)-ADHD+familial SUD (n = 17); and (3) healthy controls (HC, n = 14) who underwent one functional magnetic resonance imaging scan while performing a hybrid task. We used the omnibus analysis of covariance model to assess for group differences in brain activation in regions linked to the brain reward and behavioral control systems. Results: Behavioral analysis showed significant Cue and Flanker main effects, but no significant main effect for Group. Whole-brain analysis showed significant differences in widely distributed networks related to both reward processing and behavioral control. Region of interest (ROI) activations showed that the HR group had the highest activation in the right putamen during both expected rewards and unexpected nonreward outcomes and in the anterior cingulate cortex (ACC) during unexpected nonreward outcomes, while LR and HC youth showed similarly low activation during these contrasts. Furthermore, the LR and HR groups showed lower activation than HC in the right ACC and the right caudate during flanker contrasts. Conclusions: These are the first preliminary results to demonstrate that the magnitude of activation during reward notification differs as a function of reward outcome in youth at high versus LR for SUD, such that youth at LR for SUD exhibit the highest activation for positive rewards, whereas those at HR for SUD exhibit the highest activation during negative rewards.

Transient and sustained incentive effects on electrophysiological indices of cognitive control in younger and older adults

Preparing for upcoming events, separating task-relevant from task-irrelevant information and efficiently responding to stimuli all require cognitive control. The adaptive recruitment of cognitive control depends on activity in the dopaminergic reward system as well as the frontoparietal control network. In healthy aging, dopaminergic neuromodulation is reduced, resulting in altered incentive-based recruitment of control mechanisms. In the present study, younger adults (18-28 years) and healthy older adults (66-89 years) completed an incentivized flanker task that included gain, loss, and neutral trials. Event-related potentials (ERPs) were recorded at the time of incentive cue and target presentation. We examined the contingent negative variation (CNV), implicated in stimulus anticipation and response preparation, as well as the P3, which is involved in the evaluation of visual stimuli. Both younger and older adults showed transient incentive-based modulation of CNV. Critically, cue-locked and target-locked P3s were influenced by transient and sustained effects of incentives in younger adults, while such modulation was limited to a sustained effect of gain incentives on cue-P3 in older adults. Overall, these findings are in line with an age-related reduction in the flexible recruitment of preparatory and target-related cognitive control processes in the presence of motivational incentives.

The neural basis of motivational influences on cognitive control

Cognitive control mechanisms support the deliberate regulation of thought and behavior based on current goals. Recent work suggests that motivational incentives improve cognitive control and has begun to elucidate critical neural substrates. We conducted a quantitative meta-analysis of neuroimaging studies of motivated cognitive control using activation likelihood estimation (ALE) and Neurosynth to delineate the brain regions that are consistently activated across studies. The analysis included studies that investigated changes in brain activation during cognitive control tasks when reward incentives were present versus absent. The ALE analysis revealed consistent recruitment in regions associated with the frontoparietal control network including the inferior frontal sulcus and intraparietal sulcus, as well as regions associated with the salience network including the anterior insula and anterior mid-cingulate cortex. As a complementary analysis, we performed a large-scale exploratory meta-analysis using Neurosynth to identify regions that are recruited in studies using of the terms cognitive control and incentive. This analysis replicated the ALE results and also identified the rostrolateral prefrontal cortex, caudate nucleus, nucleus accumbens, medial thalamus, inferior frontal junction, premotor cortex, and hippocampus. Finally, we separately compared recruitment during cue and target periods, which tap into proactive engagement of rule-outcome associations, and the mobilization of appropriate viscero-motor states to execute a response, respectively. We found that largely distinct sets of brain regions are recruited during cue and target periods. Altogether, these findings suggest that flexible interactions between frontoparietal, salience, and dopaminergic midbrain-striatal networks may allow control demands to be precisely tailored based on expected value.

Reward Contingencies Improve Goal-Directed Behavior by Enhancing Posterior Brain Attentional Regions and Increasing Corticostriatal Connectivity in Cocaine Addicts

The dopaminergic system provides the basis for the interaction between motivation and cognition. It is triggered by the possibility of obtaining rewards to initiate the neurobehavioral adaptations necessary to achieve them by directing the information from motivational circuits to cognitive and action circuits. In drug addiction, the altered dopamine (DA) modulation of the meso-cortico-limbic reward circuitry, such as the prefrontal cortex (PFC), underlies the disproportionate motivational value of drug use at the expense of other non-drug reinforcers and the user's loss of control over his/her drug intake. We examine how the magnitude of the reward affects goal-directed processes in healthy control (HC) subjects and abstinent cocaine dependent (ACD) patients by using functional magnetic resonance imaging (fMRI) during a counting Stroop task with blocked levels of monetary incentives of different magnitudes (€0, €0.01, €0.5, €1 or €1.5). Our results showed that increasing reward magnitude enhances (1) performance facilitation in both groups; (2) left dorsolateral prefrontal cortex (DLPFC) activity in HC and left superior occipital cortex activity in ACD; and (3) left DLPFC and left putamen connectivity in ACD compared to HC. Moreover, we observed that (4) dorsal striatal and pallidum activity was associated with craving and addiction severity during the parametric increases in the monetary reward. In conclusion, the brain response to gradients in monetary value was different in HC and ACD, but both groups showed improved task performance due to the possibility of obtaining greater monetary rewards.

Neural Correlates of Reward Processing in Typical and Atypical Development

Atypically developing children including those born preterm or who have autism spectrum disorder can display difficulties with evaluating rewarding stimuli, which may result from impaired maturation of reward and cognitive control brain regions. During functional magnetic resonance imaging, 58 typically and atypically developing children (6-12 years) participated in a set-shifting task that included the presentation of monetary reward stimuli. In typically developing children, reward stimuli were associated with age-related increases in activation in cognitive control centers, with weaker changes in reward regions. In atypically developing children, no age-related changes were evident. Maturational disturbances in the frontostriatal regions during atypical development may underlie task-based differences in activation.

Anhedonia is associated with reduced incentive cue related activation in the basal ganglia

Research has shown that reward incentives improve cognitive control in motivationally salient situations. Much previous work in this domain has focused on incentive cue-related activity in a number of brain regions, including the dorsolateral prefrontal cortex (DLPFC) and striatum. However, the more sustained changes in functional brain activity during task contexts with incentives have been relatively less explored. Here, we examined both the cue-related and sustained effects of rewards (i.e., monetary incentives) on cognitive control, with a particular focus on the roles of the DLPFC and striatum, using a mixed state-item design. We investigated whether variability in a reward-related trait (i.e., anhedonia) would modulate the sustained and/or the cue-related transient aspects of motivated cognitive control. Twenty-seven healthy individuals performed a modified response conflict task (Padmala & Pessoa, Journal of Cognitive Neuroscience, 23, 3419-3432, 2011) during scanning, in which participants were asked to categorize images as either houses or buildings with either congruent or incongruent overlaid words. Participants performed a baseline condition without knowledge of monetary incentives, followed by reward blocks with monetary incentives on some cued trials (reward cues) for fast and correct responses. We replicated previous work by showing increases in both sustained activity during reward versus baseline blocks and transient. cue-related activity in bilateral DLPFC and the basal ganglia. Importantly, healthy individuals with higher anhedonia showed less of an increase in trial-by-trial activity as a function of reward in the lateral globus pallidus. Together, our results suggest that reduced hedonic experience may be related to abnormality of reward cue-related activity in the basal ganglia.

Happy heart, smiling eyes: A systematic review of positive mood effects on broadening of visuospatial attention

Positive mood contributes to mental and physical wellbeing. The broaden-and-build theory (Fredrickson, 2001) proposed that the beneficial effects of positive mood on life quality result from attentional broadening. In this article, we systematically review (following PRISMA guidelines; Moher et al., 2009), a host of studies investigating the nature and extent of attentional changes triggered by the experience of positive mood, with a focus on vision. While several studies reported a broadening of attention, others found that positive mood led to a more diffuse information processing style. Positive mood appears to lessen attention selectivity in a way that is context-specific and bound to limitations. We propose a new framework in which we postulate that positive mood impacts the balance between internally and externally directed attention, through modulations of cognitive control processes, instead of broadening attention per se. This novel model is able to accommodate discrepant findings, seeks to translate the phenomenon of the so-called broadening of attention with positive mood into functional terms, and provides plausible neurobiological mechanisms underlying this effect, suggesting a crucial role of the anterior and posterior cingulate cortex in this interaction.

Neural activation during risky decision-making in youth at high risk for substance use disorders

Risky decision-making, particularly in the context of reward-seeking behavior, is strongly associated with the presence of substance use disorders (SUDs). However, there has been little research on the neural substrates underlying reward-related decision-making in drug-naïve youth who are at elevated risk for SUDs. Participants comprised 23 high-risk (HR) youth with a well-established SUD risk phenotype and 27 low-risk healthy comparison (HC) youth, aged 10-14. Participants completed the balloon analog risk task (BART), a task designed to examine risky decision-making, during functional magnetic resonance imaging. The HR group had faster reaction times, but otherwise showed no behavioral differences from the HC group. HR youth experienced greater activation when processing outcome, as the chances of balloon explosion increased, relative to HC youth, in ventromedial prefrontal cortex (vmPFC). As explosion probability increased, group-by-condition interactions in the ventral striatum/anterior cingulate and the anterior insula showed increasing activation in HR youth, specifically on trials when explosions occurred. Thus, atypical activation increased with increasing risk of negative outcome (i.e., balloon explosion) in a cortico-striatal network in the HR group. These findings identify candidate neurobiological markers of addiction risk in youth at high familial and phenotypic risk for SUDs.

Methylphenidate and brain activity in a reward/conflict paradigm: role of the insula in task performance

Psychostimulants, such as methylphenidate, are thought to improve information processing in motivation-reward and attention-activation networks by enhancing the effects of more relevant signals and suppressing those of less relevant ones; however the nature of such reciprocal influences remains poorly understood. To explore this question, we tested the effect of methylphenidate on performance and associated brain activity in the Anticipation, Conflict, Reward (ACR) task. Sixteen healthy adult volunteers, ages 21-45, were scanned twice using functional magnetic resonance imaging (fMRI) as they performed the ACR task under placebo and methylphenidate conditions. A three-way repeated measures analysis of variance, with cue (reward vs. non-reward), target (congruent vs. incongruent) and medication condition (methylphenidate vs. placebo) as the factors, was used to analyze behaviors on the task. Blood oxygen level dependent (BOLD) signals, reflecting task-related neural activity, were evaluated using linear contrasts. Participants exhibited significantly greater accuracy in the methylphenidate condition than the placebo condition. Compared with placebo, the methylphenidate condition also was associated with lesser task-related activity in components of attention-activation systems irrespective of the reward cue, and less task-related activity in components of the reward-motivation system, particularly the insula, during reward trials irrespective of target difficulty. These results suggest that methylphenidate enhances task performance by improving efficiency of information processing in both reward-motivation and in attention-activation systems.

A new window to understanding individual differences in reward sensitivity from attentional networks

Existing evidence suggests that the presence of reward cues modifies the activity in attentional networks, however, the nature of these influences remains poorly understood. Here, we performed independent component analysis (ICA) in two fMRI datasets corresponding to two incentive delay tasks, which compared the response to reward (money and erotic pictures) and neutral cues, and yielded activations in the ventral striatum using a general linear model approach. Across both experiments, ICA revealed that both the right frontoparietal network and default mode network time courses were positively and negatively modulated by reward cues, respectively. Moreover, this dual neural response pattern was enhanced in individuals with strong reward sensitivity. Therefore, ICA may be a complementary tool to investigate the relevant role of attentional networks on reward processing, and to investigate reward sensitivity in normal and pathological populations.

Effect of methylphenidate on attention in apathetic AD patients in a randomized, placebo-controlled trial

BACKGROUND

Little is known about the effect of methylphenidate (MPH) on attention in Alzheimer's disease (AD). MPH has shown to improve apathy in AD, and both apathy and attention have been related to dopaminergic function. The goal was to investigate MPH effects on attention in AD and assess the relationship between attention and apathy responses.

METHODS

MPH (10 mg PO twice daily) or placebo was administered for six weeks in a randomized, double-blind trial in mild-to-moderate AD outpatients with apathy (Neuropsychiatric Inventory (NPI) Apathy ≥ 4). Attention was measured with the Wechsler Adult Intelligence Scale--Digit Span (DS) subtest (DS forward, selective attention) and apathy with the Apathy Evaluation Scale (AES). A mixed effects linear regression estimated the difference in change from baseline between treatment groups, defined as δ (MPH (DS week 6-DS baseline)) - (placebo (DS week 6-DS baseline)).

RESULTS

In 60 patients (37 females, age = 76 ± 8, Mini-Mental State Examination (MMSE) = 20 ± 5, NPI Apathy = 7 ± 2), the change in DS forward (δ = 0.87 (95% CI: 0.06-1.68), p = 0.03) and DS total (δ = 1.01 (95% CI: 0.09-1.93), p = 0.03) favored MPH over placebo. Of 57 completers, 17 patients had improved apathy (≥3.3 points on the AES from baseline to end point) and 40 did not. There were no significant associations between AES and NPI Apathy with DS change scores in the MPH, placebo, AES responder, or non-responder groups. DS scores did not predict apathy response to MPH treatment.

CONCLUSION

These results suggest MPH can improve attention and apathy in AD; however, the effects appear independent in this population.