Cognitive correlates of "pure apathy" in Parkinson's disease

Effects of Biodanza® SRT on Motor, Cognitive, and Behavioral Symptoms in Patients with Parkinson's Disease: A Randomized Controlled Study

Rolando Toro's Biodanza (SRT) is a therapeutic strategy that uses movement, music, and emotions to induce integrative living experiences. The present study aims to explore the efficacy of a three-month SRT intervention on motor, cognitive, and behavioral symptoms in patients with Parkinson's disease (PD). This study employed a randomized between-group design. Twenty-eight non-demented PD patients were enrolled in this study. Out of these, fourteen patients were assigned to the active treatment group using the Biodanza SRT system and fourteen to the untreated control group. The study group attended 2 h SRT classes once a week, completing twelve lessons in twelve weeks. All patients underwent: (i) a neurological examination to measure the severity of motor symptoms, balance, mobility, and risk of falls, and (ii) a neuropsychological battery to assess cognitive status, apathy, depressive symptomatology, and perceived quality of life (QoL), at study entry (T0) and at twelve weeks (T1, end of dance training). At T1, we observed a significant improvement in motor (i.e., severity of motor symptoms and balance) and cognitive parameters (i.e., working memory and delayed verbal memory) in all treated patients compared with the controls. Furthermore, a significant improvement in the social support dimension was found in all treated patients compared to the controls. A trend toward increased apathy was found in untreated patients at T1. The three-month Biodanza intervention significantly ameliorated the motor parameters of PD patients, with a parallel improvement in cognitive and QoL status. Hence, Biodanza intervention can, in the short term, represent a useful personalized medical intervention for the management of Parkinson's disease.

Anatomical correlates of apathy and impulsivity co-occurrence in early Parkinson's disease

BACKGROUND

Although apathy and impulse control disorders (ICDs) are considered to represent opposite extremes of a continuum of motivated behavior (i.e., hypo- and hyperdopaminergic behaviors), they may also co-occur in Parkinson's disease (PD).

OBJECTIVES

We aimed to explore the co-occurrence of ICDs and apathy and its neural correlates analyzing gray matter (GM) changes in early untreated PD patients. Moreover, we aimed to investigate the possible longitudinal relationship between ICDs and apathy and their putative impact on cognition during the first five years of PD.

METHODS

We used the Parkinson's Progression Markers Initiative (PPMI) database to identify the co-occurrence of apathy and ICDs in 423 early drug-naïve PD patients at baseline and at 5-year follow-up. Baseline MRI volumes and gray matter changes were analyzed between groups using voxel-based morphometry. Multi-level models assessed the longitudinal relationship (across five years) between apathy and ICDs and cognitive functioning.

RESULTS

At baseline, co-occurrence of apathy and ICDs was observed in 23 patients (5.4%). This finding was related to anatomical GM reduction along the cortical regions involved in the limbic circuit and cognitive control systems. Longitudinal analyses indicated that apathy and ICDs were related to each other as well as to the combined use of levodopa and dopamine agonists. Worse apathetic and ICDs states were associated with poorer executive functions.

CONCLUSIONS

Apathy and ICDs are joint non-exclusive neuropsychiatric disorders also in the early stages of PD and their co-occurrence was associated with GM decrease in several cortical regions of the limbic circuit and cognitive control systems.

Topological alteration of the brain structural network in Parkinson's disease with apathy

BACKGROUND

Apathy is a common neuropsychiatric manifestations in Parkinson's disease (PD), but neural network mechanisms still remain elusive. We aim to investigate the topological alteration of the brain structural network in PD with apathy.

METHOD

In the present study, a total of 47 apathetic PD (aPD) patients, 37 non-apathetic PD (naPD) patients, and 40 healthy controls (HCs) were enrolled. Diffusion tensor imaging (DTI) in conjunction with graph-theoretic approaches were used to explore the alterations of topological properties of the WM structural network arising from apathy in PD. One-way analysis of covariance and post hoc analyses were performed to explore differences among the three groups. Correlations were ascertained to examine relationships between the Starkstein Apathy Scale (AS) scores and significantly different network metrics among the three groups.

RESULTS

Both aPD and naPD patients remained small-world topology. However, compared with the naPD patients, aPD patients showed increased clustering coefficient (Cp) at the global level. At the regional level, aPD exhibited decreased nodal properties, mainly in the right dorsolateral prefrontal cortex (DLPFC), the right caudate nucleus (CAU), the right hippocampus, and the right superior parietal gyrus. Further, AS scores were negatively correlated with degree centrality of the right DLPFC (r = -0.254, p = 0.020) and the right CAU ( r = -0.357, p = 0.001) in the pooled patients with PD.

CONCLUSIONS

The findings suggested that apathy in PD presented relatively optimized global topological properties of the brain structural network and disrupted topological organization of the regional network, particularly involving the fronto-striatal-limbic circuits. The altered topological properties of abnormal brain regions might be used to understand the physiopathologic mechanism of the neural network in aPD patients.

Predictive factors of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping

Patients with diffuse frontal gliomas often present with post-operative apathy after tumour removal. However, the association between apathy and tumour removal of gliomas from the frontal lobe remains unknown. This study aimed to investigate the factors influencing post-operative apathy after tumour removal in patients with diffuse frontal gliomas. We compared the demographics and clinical characteristics of patients with and without post-operative apathy in a cohort of 54 patients who underwent awake brain mapping for frontal gliomas. The frequency of clinical parameters such as left-sided involvement, high-grade tumour types (WHO grades III, IV), main tumour location in the anterior cingulate gyrus (ACC) and/or dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) was significantly greater in the apathetic group compared to the non-apathetic group. The apathetic group scored significantly lower on neuropsychological assessments such as the Letter Fluency Test among the Word Fluency Tests than the non-pathetic group (p = .000). Moreover, the scores of Parts 3, and 3-1 of the Stroop test were significantly lower in the apathetic group than those in the non-apathetic group (p = .023, .027, respectively). Multivariate model analysis revealed that the appearance of post-operative apathy was significantly related to side of the of lesion [left vs. right, hazard ratio (HR) = 8.00, 95% confidence interval (CI) = 1.36-46.96, p = .021], location of the main tumour in the frontal lobe (ACC/DLPFC/OFC vs. others, HR = 7.99, 95% CI = 2.16-29.59, p = .002), and the Letter Fluency Test (HR = .37, 95% CI = .15-.90, p = .028). Post-operative apathy is significantly associated with ACC and/or DLPFC and OFC in the left hemisphere of diffuse frontal gliomas. Apathy in frontal gliomas is correlated with a decline in the Letter Fluency Test scores. Therefore, this instrument is a potential predictor of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping.

Clinical and radiological correlates of apathy in multiple sclerosis

BACKGROUND

Although apathy has been associated with fronto-striatal dysfunction in several neurological disorders, its clinical and magnetic resonance imaging (MRI) correlates have been poorly investigated in people with multiple sclerosis (PwMS).

OBJECTIVES

To evaluate clinical variables and investigate microstructural integrity of fronto-striatal grey matter (GM) and white matter (WM) structures using diffusion tensor imaging (DTI).

METHODS

A total of 123 PwMS (age: 40.25 ± 11.5; female: 60.9%; relapsing-remitting multiple sclerosis: 75.6%) were prospectively enrolled and underwent neurological and neuropsychological evaluation, including Expanded Disability Status Scale (EDSS), Apathy Evaluation Scale (AES-S), Hospital Anxiety and Depression Scale (HADS), Modified Fatigue Impact Scale (MFIS) and brain 3T-MRI volumes of whole brain, frontal/prefrontal cortex (PFC) and subcortical regions were calculated. DTI-derived metrics were evaluated in the same GM regions and in connecting WM tracts.

RESULTS

Apathetic PwMS (32.5%) showed lower education levels, higher HADS, MFIS scores and WM lesions volume than nonapathetic PwMS. Significant differences in DTI metrics were found in middle frontal, anterior cingulate and superior frontal PFC subregions and in caudate nuclei. Significant alterations were found in the right cingulum and left striatal-frontorbital tracts.

CONCLUSIONS

Apathy in PwMS is associated with higher levels of physical disability, depression, anxiety and fatigue together with lower educational backgrounds. Microstructural damage within frontal cortex, caudate and fronto-striatal WM bundles is a significant pathological substrate of apathy in multiple sclerosis (MS).

Clinimetrics of the Italian version of the Montreal Cognitive Assessment (MoCA) in adult-onset idiopathic focal dystonia

This study aimed at assessing the clinimetrics of the Montreal Cognitive Assessment (MoCA) in an Italian cohort of patients with adult-onset idiopathic focal dystonia (AOIFD). N = 86 AOIFD patients and N = 92 healthy controls (HCs) were administered the MoCA. Patients further underwent the Trail-Making Test (TMT) and Babcock Memory Test (BMT), being also screened via the Beck Depression Inventory-II (BDI-II) and the Dimensional Apathy Scale (DAS). Factorial structure and internal consistency were assessed. Construct validity was tested against TMT, BMT, BDI-II and DAS scores, whilst diagnostics against the co-occurrence of a defective performance on at least one TMT measure and on the BMT. Case-control discrimination was examined. The association between MoCA scores and motor-functional measures was explored. The MoCA was underpinned by a mono-component structure and acceptably reliable at an internal level. It converged towards TMT and BMT scores, as well as with the DAS, whilst diverging from the BDI-II. Its adjusted scores accurately detected cognitive impairment (AUC = .86) at a cut-off of < 17.212. The MoCA discriminated patients from HCs (p < .001). Finally, it was unrelated to disease duration and severity, as well as to motor phenotypes. The Italian MoCA is a valid, diagnostically sound and feasible cognitive screener in AOIFD patients.

Evaluation of apathy in non-clinical populations: validation, psychometric properties, and normative data of the Italian version of Apathy-Motivation Index (AMI)

INTRODUCTION

Evaluation of apathy in non-clinical populations is relevant to identify individuals at risk for developing cognitive decline in later stages of life, and it should be performed with questionnaires specifically designed for healthy individuals, such as the Apathy-Motivation Index (AMI); therefore, the aim of the present study was to validate the AMI in a healthy Italian population, and to provide normative data of the scale.

MATERIALS AND METHODS

Data collection was performed using a survey completed by 500 healthy participants; DAS, MMQ-A, BIS-15, PHQ-9, and GAD-7 were used to investigate convergent and divergent validity. Internal consistency and factorial structure were also evaluated. A regression-based procedure and receiver operating characteristics (ROC) analyses were used to evaluate the influence of socio-demographic variables on AMI scores and to provide adjusting factors and three cut-offs for the detection of mild, moderate, and severe apathy.

RESULTS

The Italian version of the AMI included 17 items (one item was removed because it was not internally consistent) and demonstrated good psychometric properties. The three-factor structure of AMI was confirmed. Multiple regression analysis revealed no effect of sociodemographic variables on the total AMI score. ROC analyses revealed three cut-offs of 1.5, 1.66, and 2.06 through the Youden's J statistic to detect mild, moderate, and severe apathy, respectively.

CONCLUSION

The Italian version of the AMI reported similar psychometric properties, factorial structure, and cut-offs to the original scale. This may help researchers and clinicians to identify people at risk and address them in specific interventions to lower their apathy levels.

Unawareness of Apathy in Parkinson's Disease: The Role of Executive Dysfunction on Symptom Recognition

Altered self-awareness or anosognosia may impact patients' everyday life by interfering with their safe and independent functioning. Symptom awareness has been linked to executive dysfunctions caused by damage to frontal regions. Apathy is a frequent neuropsychiatric manifestation of Parkinson's disease (PD) and is considered a consequence of altered functioning of cortico-subcortical circuitries connecting the prefrontal cortex (PFC) with the basal ganglia. Thus, apathetic PD patients may be not be fully aware of their condition due to shared neuropathophysiological mechanisms. The present study aimed to explore the awareness of apathy in PD patients by comparing the self-reported evaluations with their caregivers' ratings. Moreover, we explored the clinical predictors of possible discrepancies and their consequences on patients' self-reported evaluation of quality of life (QoL). We found a fair agreement between patients' self-reports and caregivers' ratings on apathy scores, with patients reporting less severe apathetic symptoms, especially those related to executive and auto-activation processing, compared to their caregivers' reports. Executive functioning was found to mediate the relationship between disease stage and awareness of the apathetic state. Awareness of executive apathy impacted patients' self-reported QoL. Therefore, PD patients might be unaware of their apathetic symptoms, especially those with worse executive functioning, which plays a key role in metacognitive processes such as self-monitoring and error detection. Anosognosia for apathy in PD patients may affect their QoL perception and leads to misleading self-report evaluations that delay diagnosis and treatment.

Distinct Neuropsychological Correlates of Apathy Sub-Domains in Multiple Sclerosis

Background: Apathy is relatively frequent and significantly associated with clinical and cognitive outcomes in Multiple Sclerosis (MS), even if previous research has produced mixed results. This varied picture could be due to most studies treating apathy as a unitary construct, despite the evidence showing that apathy is a multifaceted syndrome including three different sub-domains (i.e., cognitive, affective, and behavioral). This study aims to investigate the neuropsychological correlates of apathy fractionated into its three sub-domains in participants with MS. Methods: Eighty-five participants with MS underwent a comprehensive neuropsychological battery. The severity of apathy symptoms was assessed by the self-report version of the Apathy Evaluation Scale. Results: Correlational analysis showed that cognitive apathy sub-domain scores had a high correlation with the performances obtained at cognitive tests tapping into inhibitory control (i.e., IML and Strop test-interference task), whereas the affective apathy sub-domain scores had a high correlation with the performances obtained at cognitive test tapping into the use of executive functions in visuospatial abilities (i.e., Clock Drawing Test). Moreover, linear regression analysis results showed that the cognitive apathy sub-domain scores predicted executive functioning domain scores and that the cognitive and affective apathy sub-domains scores predicted visuospatial abilities domain scores. Conclusion: These results confirm that apathy is a multidimensional concept with important neuropsychological correlates, visible only when it is fractionated into its sub-domains.

Psychometrics and diagnostics of the Italian version of the Beck Depression Inventory-II (BDI-II) in Parkinson's disease

INTRODUCTION

Depression is one of the most disabling neuropsychiatric manifestations of Parkinson's disease (PD) and requires proper screening and diagnosis because it affects the overall prognosis and quality of life of patients. This study aimed to assess the psychometric and diagnostic properties of the Beck Depression Inventory-II (BDI-II) in an Italian PD cohort.

MATERIALS AND METHODS

Fifty consecutive outpatients with PD underwent the Italian version of the BDI-II and other questionnaires to evaluate anxiety and apathetic symptoms. Patients' caregivers completed the depression/dysphoria domain of the Neuropsychiatric Inventory (NPI-D). We evaluated the internal consistency, convergent and divergent validity, and factorial structure of BDI-II. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios were computed using ROC analyses, and an optimal cutoff was defined using the Youden index.

RESULTS

The BDI-II proved to be internally consistent (Cronbach's α = 0.840) and substantially met the bi-factorial structure. Regarding construct validity, the BDI-II was substantially related to anxiety measures, but not to apathy. With the combination of the NPI-D and anxiety score used as the gold standard, the BDI-II overall showed good accuracy (AUC = 0.859) with adequate sensitivity (75%) and specificity (87%). The optimal cutoff point was defined at 14.50.

CONCLUSIONS

We provide evidence of the psychometric and diagnostic properties of the Italian version of the BDI-II as a screening tool for depression in patients with PD. The BDI-II was found to be reliable and valid for the measurement of depression in patients with PD; therefore, it is available for use in clinical research and practice.

Apathy in Parkinson’s Disease: Defining the Park Apathy Subtype

Apathy is a neurobehavioural symptom affecting Parkinson’s disease patients of all disease stages. Apathy seems to be associated with a specific underlying non-motor disease subtype and reflects dysfunction of separate neural networks with distinct neurotransmitter systems. Due to the complicated neuropsychiatric aetiology of apathy, clinical assessment of this invalidating non-motor symptom remains challenging. We aim to summarize the current findings on apathy in Parkinson’s disease and highlight knowledge gaps. We will discuss the prevalence rates across the different disease stages and suggest screening tools for clinically relevant apathetic symptoms. We will approach the fundamental knowledge on the neural networks implicated in apathy in a practical manner and formulate recommendations on patient-tailored treatment. We will discuss the Park apathy phenotype in detail, shedding light on different clinical manifestations and implications for prognosis. With this review, we strive to distil the vast available theoretical knowledge into a clinical and patient-oriented perspective.

Cognitive dysfunction and neuropsychiatric aspects of Parkinson's disease

Movement abnormalities, by definition, and cognitive changes, to varying extents, affect every patient with Parkinson's disease (PD) and are attributed to the underlying neurodegenerative disease. Various psychiatric disorders occur in most patients at some point over the course of PD, including in the prodromal phase. Even though psychiatric disturbances tend to aggravate motor and cognitive deficits, they are under-recognized and under-treated, and the role of the underlying neurological disease is often minimized. To provide an integrated approach to understanding neuropsychiatric aspects of PD, this chapter reviews how cognitive changes in PD relate to the common psychiatric disturbances in PD along with the prevalence, phenomenology, pathophysiology, and treatment of each.

Neuropsychology of posteromedial parietal cortex and conversion factors from Mild Cognitive Impairment to Alzheimer's disease: systematic search and state-of-the-art review

In the present review, we discuss the rationale and the clinical implications of assessing visuospatial working memory (VSWM), awareness of memory deficits, and visuomotor control in patients with mild cognitive impairment (MCI). These three domains are related to neural activity in the posteromedial parietal cortex (PMC) whose hypoactivation seems to be a significant predictor of conversion from MCI to Alzheimer’s disease (AD) as indicated by recent neuroimaging evidence. A systematic literature search was performed up to May 2021. Forty-eight studies were included: 42 studies provided analytical cross-sectional data and 6 studies longitudinal data on conversion rates. Overall, these studies showed that patients with MCI performed worse than healthy controls in tasks assessing VSWM, awareness of memory deficits, and visuomotor control; in some cases, MCI patients’ performance was comparable to that of patients with overt dementia. Deficits in VSWM and metamemory appear to be significant predictors of conversion. No study explored the relationship between visuomotor control and conversion. Nevertheless, it has been speculated that the assessment of visuomotor abilities in subjects at high AD risk might be useful to discriminate patients who are likely to convert from those who are not. Being able to indirectly estimate PMC functioning through quick and easy neuropsychological tasks in outpatient settings may improve diagnostic and prognostic accuracy, and therefore, the quality of the MCI patient’s management.

Apathy Reflects Extra-Striatal Dopaminergic Degeneration in de novo Parkinson's Disease

BACKGROUND

Apathy represents a core neuropsychiatric symptom in Parkinson's disease (PD). As there is currently no established effective treatment for apathy in PD, further investigating the biological origin of this symptom is needed to design novel therapeutic strategies. Among the multiple neurotransmitter alterations that have been associated with apathy, the involvement of extra-striatal dopaminergic degeneration remains to be fully explored.

OBJECTIVE

To investigate whether apathy in PD reflects increased dopaminergic degeneration extending beyond striatal regions.

METHODS

In the de novo PD cohort of the Parkinson's Progression Markers Initiative (PPMI), we performed whole-brain I123-Ioflupane Single Photon Emission Computed Tomography (DAT-SPECT) analyses to characterize cross-sectional and longitudinal differences in DAT uptake associated with the presence of apathy. We also assessed the relationship between apathy and cognition in this sample, as apathy has been suggested to herald cognitive decline.

RESULTS

Apathetic PD patients (N = 70) had similar sociodemographic, clinical, and biomarker profiles compared to the non-apathetic group (N = 333) at baseline. However, apathy was associated with an increased risk of developing cognitive impairment after a four-year follow-up period (p = 0.006). Compared to non-apathetic patients, apathetic patients showed a widespread reduction of extra-striatal DAT uptake at baseline as well as an increased longitudinal loss of DAT uptake (corrected p < 0.05).

CONCLUSIONS

Isolated apathy in PD is associated with extra-striatal dopaminergic degeneration. As this abnormal dopamine depletion was in turn related to cognitive performance, this might explain, at least partially, the increased risk of apathetic PD patients to develop cognitive impairment or dementia.

Heightened effort discounting is a common feature of both apathy and fatigue

Apathy and fatigue have distinct aetiologies, yet can manifest in phenotypically similar ways. In particular, each can give rise to diminished goal-directed behaviour, which is often cited as a key characteristic of both traits. An important issue therefore is whether currently available approaches are capable of distinguishing between them. Here, we examined the relationship between commonly administered inventories of apathy and fatigue, and a measure of goal-directed activity that assesses the motivation to engage in effortful behaviour. 103 healthy adults completed self-report inventories on apathy (the Dimensional Apathy Scale), and fatigue (the Multidimensional Fatigue Inventory, and/or Modified Fatigue Impact Scale). In addition, all participants performed an effort discounting task, in which they made choices about their willingness to engage in physically effortful activity. Importantly, self-report ratings of apathy and fatigue were strongly correlated, suggesting that these inventories were insensitive to the fundamental differences between the two traits. Furthermore, greater effort discounting was strongly associated with higher ratings across all inventories, suggesting that a common feature of both traits is a lower motivation to engage in effortful behaviour. These results have significant implications for the assessment of both apathy and fatigue, particularly in clinical groups in which they commonly co-exist.

Risk Factors for Apathy in Polish Patients with Parkinson's Disease

Apathy, a feeling of indifference or a general lack of interest and motivation to engage in activity, is one of the most common neuropsychiatric symptoms in Parkinson’s disease (PD). The large variation in prevalence and the underlying pathophysiological processes remain unclear due to heterogeneous PD populations. The purpose of this study was to identify risk factors for apathy, the modification or treatment of which may be clinically relevant and improve quality of life and caregiver burden for patients with Parkinson’s disease. Caucasian subjects with Parkinson’s disease were included in the study. Baseline demographics, neurological deficit, medications taken, cognitive and neuropsychiatric status, and the polymorphisms in the brain-derived neurotrophic factor gene were assessed. Apathy was diagnosed in 53 (50.5%) patients. They were less educated (OR 0.76 CI 0.64–0.89; p = 0.001), more frequently depressed (OR 1.08 CI 1.01–1.15; p = 0.018), and less frequently treated with inhibitors of monoamine oxidase-B (MAOB-I) (OR 0.07 CI 0.01–0.69; p = 0.023). Although apathetic patients were more likely to carry the Met/Met genotype, differences in the brain-derived neurotrophic factor BDNF rs6265 polymorphism between apathetic and non-apathetic PD patients were not statistically significant in multivariate analysis. Some risk factors for apathy may be clinically modifiable. Further studies are needed to assess whether modeling modifiable apathy risk factors will affect the prevalence of this neuropsychiatric symptom in patients with Parkinson’s disease.

Alterations of regional homogeneity in Parkinson's disease with "pure" apathy: A resting-state fMRI study

BACKGROUND

Apathy is a prevalent and debilitating neuropsychiatric syndrome in Parkinson's disease (PD). However, its neural mechanisms are still unclear.

METHODS

Forty-six de novo, drug-naïve, non-demented PD patients without depressive or anxious symptoms, of whom 26 were apathetic (PD-A) and 20 were not (PD-NA) according to the Apathy Scale (AS), and 23 matched healthy control (HC) subjects were enrolled in this study. The regional homogeneity (ReHo) approach based on resting-state functional MRI on a 3-T MR system was used to investigate apathy related local brain activity.

RESULTS

Compared with both patients with PD-NA and HC subjects, patients with PD-A showed significantly lower ReHo values in the dorsal anterior cingulate cortex (ACC) and right caudate. Both the PD-A and PD-NA groups also demonstrated lower ReHo values in the right putamen compared to the HC group. Further correlation analyses revealed that AS scores were negatively correlated with the ReHo values in the dorsal ACC and right caudate in the pooled patients with PD.

LIMITATIONS

The present results are preliminary due to the small sample size in the study.

CONCLUSIONS

This study used ReHo for the first time to characterize "pure" apathy related regional spontaneous brain function within the frontostriatal circuits in PD. Our findings suggest that abnormal brain activity in the dorsal ACC and caudate may involve the pathological mechanisms of apathy in PD.

Italian version of the Starkstein Apathy Scale (SAS-I) and a shortened version (SAS-6) to assess "pure apathy" symptoms: normative study on 392 individuals

OBJECTIVES

The present normative study aimed to (1) develop the Italian version of the Starkstein Apathy Scale (SAS-I) and (2) construct a shortened version including only the most sensitive items to "pure apathy" experiences.

METHODS

The normative sample included 392 healthy subjects. A regression-based procedure was used to explore the effects of sex, age, and education on the raw SAS-I score. A correction grid was designed for adjusting raw scores by adding or subtracting the contribution of any significant variable and net of sociodemographic interindividual differences. Cutoff scores were also calculated and fixed at the external tolerance limit on the ninety-fifth centile. To obtain the shortened version, each SAS-I item was correlated with the Beck's Depression Inventory (BDI) score. The only items showing no correlation with BDI were implemented to bypass the well-known overlap between apathetic and depressive symptoms.

RESULTS

The mean raw SAS-I score was 11.27 (SD = 4.42). A significant education effect was observed, with highly educated subjects obtaining lower scores than lowly educated ones. The proposed general cutoff score was 20.68. The SAS-I had fair internal consistency and discriminant validity. Internal consistency increased by removing item 3. The new SAS-6 included items 1, 2, 4, 10, 11, and 13 of the original scale.

CONCLUSION

The SAS-I is a reliable assessment tool to support the diagnosis of apathy. The SAS-6, instead, is a brief questionnaire useful for quickly screening apathetic symptoms in outpatient practice, addressing or not the clinician to further investigations.

Mild behavioral impairment in Parkinson's disease is associated with altered corticostriatal connectivity

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Mild behavioral impairment in PD is linked to altered corticostriatal connectivity.

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PD-MBI have less connectivity between the striatum and the DMN.

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PD-MBI have increased atrophy of the SAN.

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Caudate head and dorsal putamen connectivity is related to MBI-C scores in PD.

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Caudate head-precuneus connectivity is linked to both MBI and MoCA scores.

Background

Mild behavioral impairment (MBI) is a syndrome characterized by later life onset, sustained neuropsychiatric symptoms as a marker of dementia risk. In Parkinson's disease (PD), MBI has been associated with worse cognitive abilities and increased cortical atrophy. However, the circuit level correlates of MBI have not been investigated in this population. Our objective was to investigate the relationship between MBI and corticostriatal connectivity in PD patients. This emphasis on corticostriatal connectivity was due to the significant role of these circuits in neuropsychiatric and cognitive symptoms across disease conditions.

Methods

Seventy-four non-demented patients with PD were administered the MBI-checklist, and classified as having high MBI (PD-MBI; n = 21) or low MBI scores (PD-noMBI; n = 53). Corticostriatal connectivity was assessed with both an atlas and seed-based analysis. The atlas analysis consisted of calculating the average connectivity between the striatal network and the default mode (DMN), central executive (CEN), and saliency networks (SAN). Structural measurements of cortical thickness and volume were also assessed. PD-MBI and PD-noMBI patients were compared, along with a group of age matched healthy control subjects (HC; n = 28). Subsequently, a seed analysis assessed the relationship of MBI scores with the connectivity of twelve seeds within the striatum while controlling for cognitive ability. A complementary analysis assessed the relationship between striatal connectivity and cognition, while controlling for MBI-C.

Results

PD-MBI demonstrated decreased connectivity between the striatum and both the DMN and SAN compared to PD-noMBI and HC. The decreased connectivity between the striatum and the SAN was explained partly by increased atrophy within the SAN in PD-MBI. The seed analysis revealed a relationship between higher MBI scores and lower connectivity of the left caudate head to the dorsal anterior cingulate cortex and left middle frontal gyrus. Higher MBI-C scores were also related to decreased connectivity of the right caudate head with the anterior cingulate cortex, precuneus, and left supramarginal gyrus, as well as increased connectivity to the left hippocampus and right cerebellar hemisphere. Caudate-precuneus connectivity was independently associated with both global behavioural and cognitive scores.

Conclusion

These results suggest PD-MBI is associated with altered corticostriatal connectivity, particularly between the head of the caudate and cortical regions associated with the DMN and SAN. In particular, caudate-precuneus connectivity is associated with both global behavioral and cognitive symptoms in PD.

Apathy as a behavioural marker of cognitive impairment in Parkinson's disease: a longitudinal analysis

Background

Understanding the longitudinal course of non-motor symptoms, and finding markers to predict cognitive decline in Parkinson’s disease (PD), are priorities. Previous work has demonstrated that apathy is one of the only behavioural symptoms that differentiates people with PD and intact cognition from those with mild cognitive impairment (MCI-PD). Other psychiatric symptoms emerge as dementia in PD develops.

Objective

We explored statistical models of longitudinal change to detect apathy as a behavioural predictor of cognitive decline in PD.

Methods

We followed 104 people with PD intermittently over 2 years, undertaking a variety of motor, behavioural and cognitive measures. We applied a linear mixed effects model to explore behavioural factors associated with cognitive change over time. Our approach goes beyond conventional modelling based on a random-intercept and slope approach, and can be used to examine the variability in measures within individuals over time.

Results

Global cognitive scores worsened during the two-year follow-up, whereas the longitudinal evolution of self-rated apathy scores and other behavioural measures was negligible. Level of apathy was negatively (− 0.598) correlated with level of cognitive impairment and participants with higher than average apathy scores at baseline also had poorer cognition. The model indicated that departure from the mean apathy score at any point in time was mirrored by a corresponding departure from average global cognitive score.

Conclusion

High levels of apathy are predictive of negative cognitive and behavioural outcomes over time, suggesting that apathy may be a behavioural indicator of early cognitive decline. This has clinical and prognostic implications.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09538-z) contains supplementary material, which is available to authorized users.

Source activity during emotion processing and its relationship to cognitive impairment in Parkinson's disease

BACKGROUND

Neural mechanisms contributing to an underlying cognitive impairment in Parkinson's disease (PD) are poorly understood. An effective method to probe cognitive processing deficits in PD is the examination of brain activity during emotional processes, particularly in explicit language emotion recognition contexts.

METHODS

The present study utilised cortical source imaging of event related potentials (ERP) from electroencephalography (EEG) to evaluate valence judgements on negative and neutral target words in an automatic affective priming paradigm. Fifty non-demented PD patients, unmedicated for depression or anxiety, completed affective priming tasks during EEG monitoring. Cognitive impairment was measured using the validated Parkinson's Disease-Cognitive Rating Scale (PD-CRS).

RESULTS

Results reveal that compared to healthy age-matched controls, PD patients demonstrate a reduced N400 activation during affective priming tasks in bilateral regions of the middle frontal gyrus (MFG), inferior parietal lobule (IPL) and, notably, have a late wave ERP component (LPP) in left MFG, present between 600 and 800 ms, following family-wise error correction (p_FWE < 0.05). LPP in PD patients were significantly associated with PD-CRS scores.

LIMITATIONS

Although affective priming paradigms are an effective means for various domains of cognition, it is not a focused cognitive behavioural test for cognitive dysfunction. Our study is thus limited to a surrogate measure of cognitive dysfunction via examination of emotional word processing cues.

CONCLUSIONS

These findings suggest that source imaging methods with ERP paradigms in PD are effective in identifying delayed cognitive processes in PD.