Somatization in Parkinson's Disease: A systematic review

Psychiatric Disorders and Cognitive Fluctuations in Parkinson's Disease: Changing Approaches in the First Decades of the 21st Century

Parkinson's Disease (PD) is a multifaceted neurodegenerative disorder characterized, in addition to the well-recognized motor disturbances, by a complex interplay between cognitive and psychiatric manifestations. We dissect the complex landscape of PD-related psychiatric symptoms, taking into account the impact of functional neurological disorders, somatic delusions, impulse control disorders, and conditions within the bipolar spectrum. The newer entities of somatoform and functional neurological disorders, as well as preexisting bipolar spectrum disorders, are analyzed in detail. Moreover, we emphasize the need for a holistic understanding of PD, wherein the cognitive and psychiatric dimensions are valued alongside motor symptoms. Such an approach aims to facilitate early detection and personalized interventions, and enhance the overall quality of life for individuals suffering from this neurodegenerative disorder.

Functional Movement Disorder as a Prodromal Symptom of Parkinson's Disease-Clinical and Pathophysiological Insights

Functional movement disorder (FMD) is a common manifestation of functional neurological disorder. FMD can occur alongside other neurological conditions, but especially in patients with established Parkinson's disease (PD). An interesting observation emerging across cohort studies and case series is that FMD can precede the diagnosis of PD, suggesting that FMD may itself be a prodromal symptom of neurodegeneration. Such a notion would have significant clinical implications for the assessment and management of people with FMD, particularly with respect to decisions around the use of auxiliary investigations, counselling, and follow-up. In this Viewpoint we review the evidence concerning the temporal relationship between FMD and PD. We discuss the potential explanations and mechanisms for FMD as a prodromal symptom of PD, and highlight clinical considerations and important outstanding questions in the field. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Social cognition in Parkinson's disease and functional movement disorders

INTRODUCTION

Functional movement disorders (FMD) can overlap with Parkinson's disease (PD), and distinguishing between the two clinical conditions can be complex. Framing social cognition (theory of mind) (TOM) disorder, attention deficit, and psychodynamic features of FMD and PD may improve diagnosis.

METHODS

Subjects with FMD and PD and healthy controls (HC) were administered tasks assessing TOM abilities and attention. The psychodynamic hypothesis of conversion disorder was explored by a questionnaire assessing dissociative symptoms. A comprehensive battery of neuropsychological tasks was also administered to FMD and PD.

RESULTS

Although both FMD and PD scored lower than HC on all TOM tests, significant correlations between TOM and neuropsychological tasks were found only in PD but not in FMD. Only PD showed a reduction in attentional control. Dissociative symptoms occurred only in FMD.

DISCUSSION

Cognitive-affective disturbances are real in FMD, whereas they are largely dependent on cognitive impairment in PD. Attentional control is preserved in FMD compared to PD, consistent with the hypothesis that overload of voluntary attentional orientation may be at the basis of the onset of functional motor symptoms. On a psychodynamic level, the confirmation of dissociative symptoms in FMD supports the conversion disorder hypothesis.

CONCLUSION

FMD and PD can be distinguished on an affective and cognitive level. At the same time, however, the objective difficulty often encountered in distinguishing between the two pathologies draws attention to how blurred the boundary between 'organic' and 'functional' can be.

Functional Neurological Disorders Among Patients With Tremor

OBJECTIVE

Functional neurological disorders (FNDs) are increasingly recognized in the general population and neurology clinics, and there is evidence that patients with neurological disorders are more likely to have a FND. This study was designed to identify the clinical features of FNDs among patients with movement disorders when the two disorders coexist.

METHODS

The clinical histories and video recordings of 150 consecutive patients with tremors were examined: the types of tremor included essential tremor; essential tremor plus; dystonic tremor; tremor associated with dystonia; and drug-induced, myoclonic, orthostatic, task-specific, parkinsonian, Holmes, and unclassified tremor. Using criteria for "possible" and "probable" coexistent FND, clinical features that helped differentiate between functional and other neurological tremors were identified.

RESULTS

There were 27 (18%) patients with functional manifestations, and 17 (11% of full sample) of these patients had signs suggestive of comorbid functional tremor. Patients with comorbid functional manifestations were younger at presentation, and these patients had greater severity of tremor, particularly upper limb postural tremor. Functional manifestations were not more commonly observed among patients with any particular type of tremor, except for patients with Holmes tremor, who were more likely to have comorbid functional neurological manifestations.

CONCLUSIONS

About 18% of patients with diverse types of tremors also had comorbid functional neurological manifestations. Of the coexistent FNDs, functional tremor was the most common. Patients with co-occurring functional and other neurological tremors presented for evaluation at a younger age and had greater severity of arm tremor than those without comorbid functional neurological manifestations.

Functional Neurologic Disorders, disorders to be managed by neurologists, or are neurologists wandering in a dangerous field with inadequate resources?

In recent years, some neurologists reconsidered their approach to Medically Unexplained Symptoms and proposed Functional Neurologic Disorders (FND) as a new entity, claiming that neurology could offer alternative treatment options to the psychotherapies provided in psychiatry settings. FNDs, for this purpose, should include only the disorders listed as Conversion from the Somatic Symptom and Related Disorders (SSRD) group. The present review analyzes the rationale of this position and challenges the arguments provided for its support. The review also discusses the systematization of these disorders as provided by public health systems. It outlines risks stemming from economic support and public funding uncertainty, given their negligible epidemiological dimensions resulting from the parcellation of SSRD. The review underlines the unresolved issue of Factitious Disorders, which are in the same SSRD category of the international classification but are, nonetheless, overlooked by the theoretical proponents of the FND entity. Comorbidity with other psychiatric disorders is also analyzed. We propose a model that supports the continuum between different SSRD conditions, including Factitious Disorders. The model is based on the emergence of feigned death reflex and deception from frontal lobe dysfunction. Finally, the paper summarizes the wealth of historical psychiatric and psychodynamic approaches and critical reviews. The study also puts in context the categorization and interpretation efforts provided by the most eminent researchers of the past century.

Somatoform Symptoms in Parkinson Disease

BACKGROUND

Co-occurring somatoform symptoms complicate the diagnosis and treatment of Parkinson disease (PD).

OBJECTIVE

To learn more about the relationship between somatoform symptoms and PD by comparing demographic and clinical features across PD groups differing in somatoform symptom severity.

METHOD

Using standardized Brief Symptom Inventory-18 (BSI-18) scores to measure somatoform symptom severity, we assigned 1093 individuals with PD to one of four subgroups using comparisons to normative means: low (M < -½ SD), average (M ± ½ SD), high (M +½ SD to +1 SD), very high (M > +1 SD). We used demographics and disease severity measures to assess each subgroup.

RESULTS

Most of the individuals with PD (56%) had high or very high somatoform symptom levels. Increased somatoform symptom levels were associated with female gender, lower socioeconomic status, greater disease duration, increased PD severity (Total Unified Parkinson's Disease Rating Scale), greater disability (Older Americans Resource and Services Disability subscale), increased BSI-18 Depression and Anxiety subscale scores, lower cognitive function (Mini-Mental State Examination), lower self-efficacy scores (Self-Efficacy to Manage Chronic Disease Scale), lower quality of life scores (SF-12 Health Status Survey), and greater medical comorbidity (Cumulative Illness Rating Scale-Geriatrics) (all comparisons: P < 0.001). We found no significant between-group differences for age, race, or marital status.

CONCLUSION

Somatoform symptom severity in individuals with PD is associated with greater PD severity and disability and is more common in females and in individuals with low socioeconomic status. Greater awareness of somatoform symptoms should help improve PD treatment.

Altered Medial Prefrontal Connectivity in Parkinson's Disease Patients with Somatic Symptoms

BACKGROUND

The high co-occurrence of somatic symptom disorder (SSD) in Parkinson's disease (PD) patients suggests overlapping pathophysiology. However, little is known about the neural correlates of SSD and their possible interactions with PD. Existing studies have shown that SSD is associated with reduced task-evoked activity in the medial prefrontal cortex (mPFC), a central node of the default-mode network (DMN). SSD is also associated with abnormal γ-aminobutyric acid (GABA) content, a marker of local inhibitory tone and regional hypoactivity, in the same area when SSD co-occurs with PD.

OBJECTIVES

To disentangle the individual and shared effects of SSD and PD on mPFC neurotransmission and connectivity patterns and help disclose the neural mechanisms of comorbidity in the PD population.

METHODS

The study cohort included 18 PD patients with SSD (PD + SSD), 18 PD patients, 13 SSD patients who did not exhibit neurologic disorders, and 17 healthy subjects (HC). Proton magnetic resonance (MR) spectroscopy evaluated GABA levels within a volume of interest centered on the mPFC. Resting-state functional MR imaging investigated the region's functional connectivity patterns.

RESULTS

Compared to HC or PD groups, the mPFC of SSD subjects exhibited higher GABA levels and connectivity. Higher mPFC connectivity involved DMN regions in SSD patients without PD and regions of the executive and attentional networks (EAN) in patients with PD comorbidity.

CONCLUSIONS

Aberrant reconfigurations of connectivity patterns between the mPFC and the EAN are distinct features of the PD + SSD comorbidity. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Hopkins Symptom Checklist (SCL-90-R): A Patient-Reported Outcome Measure in Parkinson's Disease

Objective: This is the first study applying Clinimetric Patient-Reported Outcome Measures (CLIPROM) criteria to evaluate the construct validity, sensitivity, and clinical utility of the SCL-90-R in patients with Parkinson's disease (PD). Methods: A Rasch analysis was conducted using a sample of 488 PD outpatients. Results: Testing for dimensionality revealed that less than 5% of t-tests were significant, indicating that the SCL-90-R subscales entailed the property of construct validity. As to the total score, a Person Separation Reliability Index of .96 was found. Conclusions: The SCL-90-R total score is a sensitive screening measure that can be used not only to differentiate healthy stress reactions from symptoms of psychological distress but also to detect PD patients with an increased risk for psychiatric complications. As to the subscales, the brief versions that did not include misfitting items should be used to assess the severity of specific symptoms of psychological distress affecting PD patients.

Mentalization and dissociation after adverse childhood experiences

.Impairment of mentalization may impact coping strategies, regulation of affect and stress. The influence of impaired mentalization on dissociation in patients with adverse childhood experiences (ACEs) could be important for treatment strategies. The aim of this study is to assess the relationship between ACEs, mentalizing and dissociation in adult individuals. Sixty-seven patients with ACEs completed the Mentalization Questionnaire (MZQ), the Essener Trauma Inventory (ETI) and the Brief Symptom Inventory-18 (BSI-18). The SPSS PROCESS macro tool was applied to test if mentalization mediated the relationship of ACEs and dissociation. ACEs were significantly associated with higher dissociation (β = 0.42, p < 0.001) and lower mentalization (β = - 0.49, p < 0.001). When mentalization was added to the model as a predictor, the association of ACEs with dissociation was no longer significant (β = 0.11, p = 0.31) and a statistically significant indirect effect was found (β = 0.32, 95% CI 0.16-0.47). The overall explained variance of dissociation notably improved after inclusion of mentalization (17.5% to 49.1%). Thus, the results indicated that the association of ACEs on dissociation was fully mediated by mentalization. Our results suggest that ACEs are associated with lower mentalization and higher dissociation. Lower mentalization was also associated with worse depression, anxiety, somatization and PTSD symptoms. These findings underline the increasing importance of early treatment of individuals affected by ACEs with a focus to foster the development of mentalization.

History of Functional Somatic Syndromes and Persistent Symptoms After Mild Traumatic Brain Injury

OBJECTIVE

Somatization is thought to underlie functional somatic syndromes (FSSs) and may also contribute to prolonged symptoms after mild traumatic brain injury (mTBI). The investigators evaluated the prevalence of FSSs in patients seeking specialty care after mTBI and whether a history of FSSs was associated with symptom persistence.

METHODS

A total of 142 patients with mTBI completed questionnaires regarding demographic information, injury characteristics, and medical history, including history of diagnosed FSSs at clinic intake (mean=41 days postinjury [SD=22.41]). Postconcussion symptoms were assessed at clinic intake and again 1 and 3 months later. A linear mixed-effects model was used to determine whether history of FSSs was related to persistent mTBI symptoms over time.

RESULTS

A history of at least one FSS was reported by 20.4% of patients. In the linear mixed model, postconcussion symptom scores were not significantly different over time among patients with a history of one or more FSSs or two or more FSSs from those with no FSSs. A history of one or more FSSs or two or more FSSs (versus no FSS) was not associated with increased odds of severe postconcussion symptoms at clinic intake (one or more FSSs: odds ratio=0.88, 95% CI=0.38-2.03; two or more FSSs: odds ratio=1.78, 95% CI=0.45-7.03), at the 1-month follow-up visit (one or more FSSs: odds ratio=0.57, 95% CI=0.22-1.45; two or more FSSs: odds ratio=0.57, 95% CI=0.14-2.37), or at the 3-month follow-up visit (one or more FSSs: odds ratio=0.97, 95% CI=0.36-2.63; two or more FSSs: odds ratio=1.27, 95% CI=0.29-5.65).

CONCLUSIONS

In this sample, the prevalence rates of FSSs were higher than rates previously reported for the general population. However, FSS history did not predict higher postconcussion symptom burden at clinic intake or persistence over the following 3 months. Further research is needed to clarify the potential role of somatization in poor mTBI outcome.

Amyloid-β42/Neurogranin Ratio as a Potential Index for Cognitive Impairment in Parkinson's Disease

BACKGROUND

Synaptopathy is critical in pathophysiology of Parkinson's disease (PD). Cerebrospinal fluid (CSF) levels of neurogranin (NG) and amyloid-β42 (Aβ42) are considered markers of synaptic dysfunction in neurodegenerative diseases.

OBJECTIVE

To evaluate the CSF synaptopathy-related biomarkers, especially the novel Aβ42/NG ratio, in PD, establishing possible associations with cognitive level and other clinical parameters.

METHODS

Levels of NG, Aβ42, amyloid-β40, total and phosphorylated tau, and Aβ42/NG ratio were measured in 30 PD patients and 30 controls and correlated with cognitive and motor parameters. The accuracy in distinguishing the cognitive status was determined.

RESULTS

NG and Aβ42 were significantly reduced in PD, with higher NG levels in patients with worse cognition. The Aβ42/NG ratio showed a direct correlation with Mini-Mental State Examination, independently from age and sex, and differentiated cognitively impaired patients with 92% sensitivity and 71.4% specificity, accuracy higher than NG alone. No correlations resulted with motor disturbances or therapy.

CONCLUSIONS

The novel Aβ42/NG ratio couples either presynaptic or postsynaptic markers of synaptic dysfunction, representing a potential global index of synaptopathy, useful to track cognitive functions in PD.

Association Between Somatization and Nonmotor Symptoms Severity in People With Parkinson Disease

OBJECTIVE

To assess the frequency of somatization and its association with motor, nonmotor symptoms, and quality of life in persons with Parkinson disease (PD).

METHODS

A cross-sectional case-control study was carried out. Assessments included the List of 90 Symptoms somatic factor (SCL-90-R SOM), Movement Disorder Society Unified Parkinson's Ratings Scale (MDS-UPDRS), Non-Motor Symptom Scale (NMSS), Montreal Cognitive Assessment (MoCA), and Parkinson Questionnaire-8 (PDQ-8).

RESULTS

A total 93 persons with PD and 93 controls were included. Somatization within the PD group was 2 times more frequent compared to the control group (43% vs 21.5%, P = .003). Persons with PD had higher NMSS total scores (48.6 ± 42.6 vs 28.3 ± 30.4, P = .001). Patients with PD with somatization had worst MDS-UPDRS, NMSS, MoCA, and PDQ-8 (all P < .05).

CONCLUSION

Somatization is more frequent in persons with PD compared to healthy controls. Somatization in PD is associated with nonmotor symptoms and worst quality of life.

Functional movement disorder comorbidity in Parkinson's disease: Unraveling the web

Functional movement disorders are commonly seen in neurology services and may coexist with other neurological diseases. This combination is known as "functional overlay" and an increasing interest on this topic has emerged in the past decade as the field of functional neurological disorders has moved forward. Some neurological diseases may be more prone to develop "functional overlay" than others, and within the field of movement disorders, most studies have focused on patients with Parkinson's disease. This review comprehensively summarizes the current body of knowledge on this topic and provides an expert opinion to equip clinicians with a pragmatic approach to recognize functional movement disorders in patients with Parkinson's disease, to communicate the diagnosis and to become familiar with potential therapies in this complex clinical scenario. Potential underlying mechanisms and risk factors that may play a role in increasing the vulnerability of Parkinson's disease patients to develop functional movement disorder comorbidity are also discussed within the framework of modern neurobiological theories of brain functioning.

Factor Structure and Psychometric Properties of the Body Perception Questionnaire-Short Form (BPQ-SF) Among Chinese College Students

Objective

Body perception, including body awareness and reactivity, is featured in a range of mental health conditions. However, research on Chinese questionnaires assessing body perception has been surprisingly absent. The present study aimed to investigate the factor structure and psychometric properties of the Body Perception Questionnaire–Short Form (BPQ-SF) among Chinese.

Methods

the current sample included 688 Chinese college students. Self-report scales were used to measure body perception, somatization, and depressive somatic and psychological symptoms.

Results

Confirmatory factor analysis supported a three-factor model of the BPQ-SF, involving body awareness, supradiaphragmatic reactivity, and subdiaphragmatic reactivity. Good internal consistency and test–retest reliability were observed. Convergent validity was established by significant correlations with scores of somatization and somatic symptoms of depression. Divergent validity was evidenced by non-significant association with ratings on psychological symptoms of depression. The very short form of the body awareness subscale of BPQ can be an alternative to the body awareness subscale when scale length is the priority.

Conclusion

The BPQ-SF possessed three latent factors and demonstrated good psychometric properties that can measure body perception among Chinese in a reliable and valid way.

Clinimetric approach to rating scales for the assessment of apathy in Parkinson's disease: A systematic review

A number of rating scales for the assessment of apathy in Parkinson's disease (PD) were developed. Unfortunately, previous studies focused mainly on psychometric criteria rather than on clinimetric principles to develop these assessment instruments. In the clinimetric approach, the clinical validity of a rating scale, rather than its statistical significance, has the priority. The aim of the present systematic review was to capture the clinimetric properties of these rating scales and to identify the measures, which display clinical validity for the assessment of apathy in PD. The systematic search was conducted on Scopus, PsycINFO, PubMed, Web of Science, ScienceDirect, and Medline following the PRISMA guidelines. A total of 44 studies were included and analyzed in this systematic review. The apathy rating scales, which were found to be psychometrically robust and reliable, were actually clinically questionable. The apathy measures, which displayed clinimetric properties, were the Starkstein Apathy Scale (SAS), the 5-item version of the World Health Organization Well-Being Index (WHO-5), the Neurasthenia Scale and the Lille Apathy Rating Scale (LARS). The SAS was found to be clinically valid at a macro-analytic level, particularly when used either to exclude the presence of symptoms of apathy or to evaluate the side effects of medications. The WHO-5 and the Neurasthenia Scale were found to be clinically valid only at a micro-analytic level and can be used as screening measures for the assessment of the severity of symptoms of apathy. The LARS was a clinically valid instrument to be used for the diagnosis of apathy.

Somatic symptoms disorders in Parkinson's disease are related to default mode and salience network dysfunction

Background

Somatic Symptoms Disorder (SSD) has been shown to have a clinically very high prevalence in Parkinson's Disease (PD) with frequencies ranging from 7.0% to 66.7%, higher than in the general population (10%- 25%).

SSD has been associated with dysfunction in Default Mode and Salience network.

Aim

With the present study we aim to verify by means of resting state functional MRI whether possible specific abnormalities in the activation and functional connectivity of the default mode network (DMN) and salience network in cognitively intact PD patients may be more prominent in PD patients with somatic symptoms (SSD-PD) as compared with patients without SSD (PD).

Methods

Eighteen SSD-PD patients (61% male), 18 PD patients (83% male) and 22 healthy age-matched subjects (59% male) were enrolled in the study and underwent resting state functional MRI.

Results

fractional amplitude of low-frequency fluctuation (fALFF) showed reduced activity in bilateral lateral parietal cortex and in left anterior insula in both SSD-PD and PD compared to control group. Functional connectivity (FC) values in the DMN areas and between DMN and salience network areas were found to be lower in SSD-PD than in control group and PD. No significant correlation was found between fMRI results and demographic and clinical variables, excluding the effect of possible confounders on fMRI results.

The present study, showing reduced activity in bilateral parietal areas and in the left anterior insula as compared to healthy controls, suggests a dysfunction of the DMN and salience network in PD, either with or without SSD.

The FC reduction within DMN areas and between DMN and salience network areas in SSD-PD patients suggests a role of dysfunctional connectivity in the resting state network of patients with SSD.

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Reduced activity in parietal areas and in anterior insula in Parkinson's Disease.

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Functional connectivity is lower in Parkinson's disease with somatic symptoms.

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Somatic Symptoms in PD are related to default mode and salience network alterations.

Hallucinations, somatic-functional disorders of PD-DLB as expressions of thalamic dysfunction

Hallucinations, delusions, and functional neurological manifestations (conversion and somatic symptom disorders) of Parkinson's disease (PD) and dementia with Lewy bodies increase in frequency with disease progression, predict the onset of cognitive decline, and eventually blend with and are concealed by dementia. These symptoms share the absence of reality constraints and can be considered comparable elements of the PD-dementia with Lewy bodies psychosis. We propose that PD-dementia with Lewy bodies psychotic disorders depend on thalamic dysfunction promoting a theta burst mode and subsequent thalamocortical dysrhythmia with focal cortical coherence to theta electroencephalogram rhythms. This theta electroencephalogram activity, also called fast-theta or pre-alpha, has been shown to predict cognitive decline and fluctuations in Parkinson's disease with dementia and dementia with Lewy bodies. These electroencephalogram alterations are now considered a predictive marker for progression to dementia. The resulting thalamocortical dysrhythmia inhibits the frontal attentional network and favors the decoupling of the default mode network. As the default mode network is involved in integration of self-referential information into conscious perception, unconstrained default mode network activity, as revealed by recent imaging studies, leads to random formation of connections that link strong autobiographical correlates to trivial stimuli, thereby producing hallucinations, delusions, and functional neurological disorders. The thalamocortical dysrhythmia default mode network decoupling hypothesis provides the rationale for the design and testing of novel therapeutic pharmacological and nonpharmacological interventions in the context of PD, PD with dementia, and dementia with Lewy bodies. © 2019 International Parkinson and Movement Disorder Society.

Functional movement disorders in neurogeriatric inpatients : Underdiagnosed, often comorbid to neurodegenerative disorders and treatable

BACKGROUND

The proportion of patients with functional movement disorders (FMD) is particularly high in neurology clinics. Treatment options have not been consistently developed, not well evaluated and not validated. This article presents the preliminary data on the prevalence and treatment response of patients with FMD who were treated within the framework of an early rehabilitative geriatric complex treatment at a university hospital for neurology.

METHODS

From July 2017 to November 2018 the prevalence, demographic and clinical parameters, and response to treatment of FMD patients were documented and compared to non-FMD patients treated at the neurogeriatric ward of the University Hospital Schleswig-Holstein, in Kiel. Clinical endpoints were the Short Physical Performance Battery (SPPB) for mobility and the Barthel index for instrumented activity of daily life (iADL).

RESULTS

The prevalence of FMD was 11% (19/175) and predominantly observed in women (74%). Of the FMD patients nine also had a diagnosis of either idiopathic Parkinson's disease (N = 7), dementia with Lewy bodies (N = 1) or progressive supranuclear palsy (N = 1). At admission, neither the SPPB nor the iADL differed significantly between FMD and non-FMD patients. The treatment response was comparable between the groups: SPPB change was +0.3±1.8 (mean, standard deviation) in FMD and +0.4±1.9 in non-FMD patients (p = 0.83). The iADL change was +19±15 in FMD and +18±17 in non-FMD (p = 0.83).

CONCLUSION

The prevalence of FMD was unexpectedly high in the neurogeriatric ward of a German university hospital. There were comparable impairments and responses to multidisciplinary treatment in mobility and iADL between FMD and non-FMD geriatric patients, suggesting that specific and informed treatment provided by a multidisciplinary geriatric team is effective in geriatric FMD patients. Further studies of this underdiagnosed disorder in older age are warranted.

The prevalence of psychological distress in Parkinson's disease patients: The brief symptom inventory (BSI-18) versus the Hopkins symptom checklist (SCL-90-R)

The prevalence of psychological distress in Parkinson's disease (PD) patients has been evaluated by many different assessment instruments and with diverse control groups. The most frequently used distress symptom scale has been the Hopkins Symptom Checklist (SCL-90-R), although it contains many symptoms with problematic validity clinically. The 18-item subscale of the SCL-90-R, the Brief Symptom Inventory (BSI-18) has recently been shown to have a sufficient validity to screen for the prevalence of psychological distress (somatization) in PD patients. We have performed a clinimetric analysis by comparing the BSI-18 with SCL-90-R relevant subscales in PD patients. Our micro-analysis has focused on the Mokken model to test the scalability of the subscales. The macro-analysis has focused both on effect size statistics and the normative level of psychological distress with reference to the Italian general population data using T-score metric. The Mokken analysis indicated acceptable scalability for all the subscales of BSI-18. The effect size statistics identified somatization in both BSI-18 and SCL-90-R as the most prevalent and intense symptom of psychological distress. The T-score metric identified the phobic anxiety subscale of SCL-90-R to be clinically much more important than the BSI-18 anxiety subscale in the PD patients. We have found the SCL-90-R subscale of phobic anxiety and the BSI-18 somatization subscale most clinically valid when measuring psychological distress in PD patients.

Impact of non-motor symptoms in Parkinson's disease: a PMDAlliance survey

PURPOSE

Parkinson's disease (PD) is associated with non-motor symptoms (NMS) that can cause progressive disability and impact quality of life of people with PD (PwP) and increase burden on care partners. This survey was designed to evaluate the prevalence, impact, and educational preferences regarding NMS on PwP and their care partners.

PATIENTS AND METHODS

A 17-question survey was sent to the total membership of PMDAlliance, a nonprofit organization reaching 3,685 households of PwP. Care partners and other interested individuals could also respond. The survey was conducted using Survey Monkey, an online survey platform, and included distinct questions for respondents with and without NMS.

RESULTS

A total of 700 individuals responded to the survey. Of the respondents, 378 (54%) were care partners and 287 (41%) were PwP. About 90% of the respondents reported having experience with NMS in PwP, including sleep problems (84%), cognitive symptoms (76%), anxiety (65%), depression (56%), hallucinations (40%), and delusions (23%). NMS in PwP were reported by more care partners (97%) than PwP (80%). NMS had at least some impact on quality of life for 84% of the respondents; 48% indicated that NMS represented a greater challenge than motor symptoms. Care partners were more likely than PwP to report that NMS were more challenging than motor symptoms (58% vs 32%). Respondents with and without NMS indicated a desire for NMS education.

CONCLUSION

This survey underscores the significant impact of NMS on the quality of life of PwP and highlights the need for improved recognition and education about its effects.

Alexithymia in Gastroenterology and Hepatology: A Systematic Review

Background: Alexithymia is a multifaceted personality construct that represents a deficit in the cognitive processing of emotions and is currently understood to be related to a variety of medical and psychiatric conditions. The present review aims to investigate the relationship of alexithymia with gastrointestinal (GI) disorders as functional gastrointestinal disorders (FGID, as irritable bowel syndrome (IBS) and functional dyspepsia) and inflammatory bowel disease (IBD) [ulcerative colitis (UC) and Crohn's disease (CD)] and liver diseases as chronic hepatitis C (CHC), cirrhosis, and liver transplantation. Methods: The articles were selected from the main electronic databases (PsycInfo, Medline, PubMed, Web of Science, Scopus, Cochrane, and ScienceDirect) using multiple combinations of relevant search terms (defined GI and liver diseases, articles in English, use of the Toronto scales [TAS] for alexithymia). The TAS was selected as inclusion criterion because it is the most widely used measure, thus allowing comparisons across studies. Results: Forty-eight studies met the inclusion criteria, of which 38 focused on GI disorders (27 on FGID and 11 on IBD) and 10 on liver diseases. Most studies (n = 30, 62%) were cross-sectional. The prevalence of alexithymia was higher in FGID (two third or more) than IBD and liver diseases (from one third to 50% of patients, consistent with other chronic non-GI diseases) than general population (10-15%). In functional disorders, alexithymia may be viewed as a primary driver for higher visceral perception, symptom reporting, health care use, symptom persistence, and negative treatment outcomes. Also, it has been found associated with psychological distress and specific GI-related forms of anxiety in predicting symptom severity as well as post-treatment outcomes and is associated with several psychological factors increasing the burden of disease and impairing levels of quality of life. A number of critical issues (small sample sizes, patients referred to secondary and tertiary care centers, cross-sectional study design, use of one single scale for alexithymia) constitutes a limitation to the generalization of findings. Conclusions: Alexithymia showed to play different roles in gastroenterology according to the clinical characteristics and the psychological burden of the various disorders, with main relevance in increasing subjective symptom perception and affecting negatively post-treatment outcomes.

Evaluating psychiatric symptoms in Parkinson's Disease by a clinimetric analysis of the Hopkins Symptom Checklist (SCL-90-R)

Although psychiatric comorbidity in Parkinson's Disease (PD) has often been studied, the individual psychiatric symptoms have rarely been evaluated from a clinimetric point of view in an attempt to measure how much the symptoms have been bothering or distressing the PD patients. The current study is therefore aimed at evaluating from a clinimetric viewpoint the severity of psychiatric symptoms affecting PD patients by using the Hopkins Symptom Checklist (SCL-90-R) to show its measurement-driven construct validity (scalability). The conventional nine SCL-90-R subscales (somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideas, and psychoticism), as well as the clinical most valid subscales from the SCL-28 version (depression, anxiety, interpersonal sensitivity, and neurasthenia) were analysed according to a clinimetric approach by comparing PD patients with a control group from a general population study. Scalability was tested by the non-parametric item response theory model by use of a Mokken analysis. Among the various SCL-90-R or SCL-28 subscales we identified from the clinimetric analysis that the somatization, anxiety, phobic anxiety, psychoticism, and neurasthenia (apathy), as well as the SCL-90-R GSI, were the most impaired psychiatric syndromes reaching a clinically significant effect size above 0.80, whereas the total SCL-28 GSI obtained an effect size of just 0.80. Our clinimetric analysis has shown that patients with PD not only are bothered with diverse somatic symptoms, but also with specific secondary psychiatric comorbidities which are clinically severe markers of impairment in the day-to-day function implying a negative cooping approach.