Impact of the COVID-19 pandemic on the symptomatology and routine of medicated patients with obsessive-compulsive disorder

Objectives: To study the impact of coronavirus disease 2019 on the routine of patients with obsessive-compulsive disorder (OCD) and changes in symptoms and suicidal-related behavior, mainly in those with cleaning symptoms. Methods: In this cross-sectional study, 58 patients completed an online self-report questionnaire that included the Obsessive-Compulsive Inventory-Revised, Coronavirus Stress and Traumatic Events Scale, Coronavirus Health Impact Survey, Beck Anxiety and Beck Depression inventories, and Suicide-Related Behaviors Questionnaire. Comparisons were made with another pre-pandemic sample (n=524) regarding the last three measures. Results: During the pandemic, the patients spent more days inside their homes (χ2 = 33.39, p = 0.007), changed their alcohol consumption patterns (χ2 = 87.6, p < 0.001), and increased social media usage (χ2 = 68.83, p < 0.001). Participants with cleaning symptoms did not significantly differ from the others in relation to stress, anxiety/depressive symptoms, or suicidal-related behaviors. Finally, our sample did not differ from an equivalent OCD sample assessed before the pandemic in terms of anxiety and depressive symptom severity or suicidal-related behaviors. Conclusion: Overall, patients with OCD showed no lifestyle changes associated with higher stress levels during the pandemic. Patients with and without cleaning symptoms and patients before and during the pandemic presented similar results.

Neurocircuit models of obsessive-compulsive disorder: limitations and future directions for research

Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.

Neuroimaging and electroencephalographic (EEG) methods for investigating neural circuits in mental disorders / Métodos de neuroimagem e eletroencefalografia (EEG) para investigação de circuitos neurais em transtornos mentais

It is increasingly recognised that dysfunction in neural circuits plays a key role in the neurobiological basis of mental disorders. The efficacy of pharmacological and behavioural treatments for mental disorders could therefore be improved by targeting dysfunctions in neurocircuits. However, to achieve this, a better understanding of the specific alterations in neural circuits involved in different mental disorders is required. Such understanding can be acquired by using advanced neuroscience methods to examine the pathways and function of neurocircuits in both typically developing individuals and in those with mental disorders. This article provides an overview of currently available neuroscience methods of investigating neural circuits, including advantages and limitations of different techniques, and highlights the importance of using multi-modal imaging in future research.

É cada vez mais reconhecido que a disfunção nos circuitos neurais desempenha um papel fundamental na base neurobiológica dos transtornos mentais. A eficácia dos tratamentos farmacológicos e comportamentais para os transtornos mentais pode, portanto, ser melhorada por direcionar as disfunções nos neurocircuitos. No entanto, para isso, é necessário um melhor entendimento das alterações específicas nos circuitos neurais envolvidos em diferentes transtornos mentais. Tal entendimento pode ser adquirido usando-se métodos avançados de neurociência para examinar as vias e a função dos neurocircuitos em indivíduos com desenvolvimento típico e naqueles com transtornos mentais. Este artigo fornece uma visão geral dos métodos da neurociência atualmente disponíveis na investigação de circuitos neurais, incluindo vantagens e limitações de diferentes técnicas, e destaca a importância do uso de imagens multimodais em pesquisas futuras.

Theoretical models of Obsessive-Compulsive Disorder (OCD): a perspective on future approaches

Obsessive-Compulsive disorder (OCD) is a common psychiatric condition that leads to significant impairment in everyday life. Advancements in neurobiological investigations contributed to a better understanding of pathophysiological mechanisms behind OCD, leading to the understanding that current models employed to conceptualize OCD are not adequate and might be a significant factor in precluding further advancements in how OCD is treated. In this paper, we will use OCD as a model to discuss the limitations of the current diagnostic systems in Psychiatry and to present the novel perspectives based on neurobiological findings that might lead to considerable advancements in treatments for OCD.

No evidence of attentional bias toward angry faces in patients with obsessive-compulsive disorder

Objective: Although attentional bias (AB) toward angry faces is well established in patients with anxiety disorders, it is still poorly studied in obsessive-compulsive disorder (OCD). We investigated whether OCD patients present AB toward angry faces, whether AB is related to symptom severity and whether AB scores are associated with specific OCD symptom dimensions. Method: Forty-eight OCD patients were assessed in clinical evaluations, intelligence testing and a dot-probe AB paradigm that used neutral and angry faces as stimuli. Analyses were performed with a one-sample t-test, Pearson correlations and linear regression. Results: No evidence of AB was observed in OCD patients, nor was there any association between AB and symptom severity or dimension. Psychiatric comorbidity did not affect our results. Conclusion: In accordance with previous studies, we were unable to detect AB in OCD patients. To investigate whether OCD patients have different brain activation patterns from anxiety disorder patients, future studies using a transdiagnostic approach should evaluate AB in OCD and anxiety disorder patients as they perform AB tasks under functional neuroimaging protocols.

The validity and reliability of the CAMDEX-DS for assessing dementia in adults with Down syndrome in Brazil

Objective: Alzheimer's disease occurs at a higher prevalence and an earlier age in individuals with Down syndrome (DS) than typically developing individuals. However, diagnosing dementia in individuals with intellectual disability remains a challenge due to pre-existing cognitive deficits. The aim of this study was to investigate the validity and reliability of the Brazilian version of the Cambridge Examination for Mental Disorders of Older People with Down's syndrome and Others with Intellectual Disabilities (CAMDEX-DS) for individuals with DS. Methods: Two psychiatrists, working independently, evaluated 92 adults with DS ≥ 30 years of age. The concurrent validity of the CAMDEX-DS was analyzed in relation to the gold standard of established international criteria. In a subgroup of 20 subjects, the concurrent validity of the CAMDEX-DS was analyzed in relation to an independent objective assessment of cognitive decline over three years. We analyzed the inter-rater reliability of cognitive assessment. Results: The diagnostic accuracy of the CAMDEX-DS compared to the gold standard was 96.7%. CAMDEX-DS-based diagnosis was considered consistent with cognitive decline. The probability of a participant with dementia having cognitive decline was 83%. Inter-rater reliability for the participant assessment was good, with a kappa of > 0.8 for 93% of the CAMDEX-DS items. Conclusion: The CAMDEX-DS can be considered the first valid and reliable instrument for evaluating dementia in adults with DS in Brazil. Its use in such individuals could improve clinical practice and research.

Evolution of gamma knife capsulotomy for intractable obsessive-compulsive disorder.

For more than half a century, stereotactic neurosurgical procedures have been available to treat patients with severe, debilitating symptoms of obsessive-compulsive disorder (OCD) that have proven refractory to extensive, appropriate pharmacological, and psychological treatment. Although reliable predictors of outcome remain elusive, the establishment of narrower selection criteria for neurosurgical candidacy, together with a better understanding of the functional neuroanatomy implicated in OCD, has resulted in improved clinical efficacy for an array of ablative and non-ablative intervention techniques targeting the cingulum, internal capsule, and other limbic regions. It was against this backdrop that gamma knife capsulotomy (GKC) for OCD was developed. In this paper, we review the history of this stereotactic radiosurgical procedure, from its inception to recent advances. We perform a systematic review of the existing literature and also provide a narrative account of the evolution of the procedure, detailing how the procedure has changed over time, and has been shaped by forces of evidence and innovation. As the procedure has evolved and adverse events have decreased considerably, favorable response rates have remained attainable for approximately one-half to two-thirds of individuals treated at experienced centers. A reduction in obsessive-compulsive symptom severity may result not only from direct modulation of OCD neural pathways but also from enhanced efficacy of pharmacological and psychological therapies working in a synergistic fashion with GKC. Possible complications include frontal lobe edema and even the rare formation of delayed radionecrotic cysts. These adverse events have become much less common with new radiation dose and targeting strategies. Detailed neuropsychological assessments from recent studies suggest that cognitive function is not impaired, and in some domains may even improve following treatment. We conclude this review with discussions covering topics essential for further progress of this therapy, including suggestions for future trial design given the unique features of GKC therapy, considerations for optimizing stereotactic targeting and dose planning using biophysical models, and the use of advanced imaging techniques to understand circuitry and predict response. GKC, and in particular its modern variant, gamma ventral capsulotomy, continues to be a reliable treatment option for selected cases of otherwise highly refractory OCD.

Obsessive-Compulsive Personality Symptoms Predict Poorer Response to Gamma Ventral Capsulotomy for Intractable OCD.

Gamma ventral capsulotomy (GVC) is a radiosurgical procedure which aims to create lesions in the ventral part of the anterior limb of the internal capsule (ALIC). It has been used as a treatment option for patients with intractable obsessive-compulsive disorder (OCD) who do not respond to several first-line treatments attempts. However, changes in personality disorder symptoms after GVC have not been investigated. The aims of this study are to investigate changes in personality disorder symptoms after GVC and to search for baseline personality disorder symptoms that may predict clinical response to GVC. Fourteen treatment-intractable OCD patients who underwent GVC completed the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II) at baseline and one year after the procedure. Wilcoxon signed-rank test was performed to investigate personality disorder symptom changes before and after surgery. Linear regression models were utilized to predict treatment response, using baseline personality disorder symptoms as independent variables. We did not observe any quantitative changes in personality disorder symptoms after GVC, compared with baseline. Higher severity of obsessive-compulsive personality disorder symptoms at baseline was correlated with worse treatment response after GVC for OCD (ß = -0.085, t-value = -2.52, p-value = 0.027). These findings advocate for the safety of the GVC procedure in this specific population of intractable OCD patients, in terms of personality disorder symptom changes. They also highlight the importance of taking into account the severity of obsessive-compulsive personality disorder symptoms when GVC is indicated for intractable OCD patients.

Personality measures after gamma ventral capsulotomy in intractable OCD.

BACKGROUND: Neurosurgeries such as gamma ventral capsulotomy (GVC) are an option for otherwise intractable obsessive-compulsive disorder (OCD) patients. In general, clinical and neuropsychological status both improve after GVC. However, its consequences on personality traits are not well-studied. The objective of this study was to investigate personality changes after one year of GVC in intractable OCD patients. METHODS: The personality assessment was conducted using the Revised NEO Personality Inventory (NEO PI-R) and Cloninger's Temperament and Character Inventory (TCI) in 14 intractable OCD patients before and one year after GVC. Comparisons of personality features between treatment responders (n=5) and non-responders (n=9) were performed. Multiple linear regression was also used for predicting changes in clinical and global functioning variables. RESULTS: Overall, no deleterious effect was found in personality after GVC. Responders had a reduction in neuroticism (p=0.043) and an increase in extraversion (p=0.043). No significant changes were observed in non-responders. Increases in novelty seeking and self-directedness, and decreases in persistence and cooperativiness predicted OCD symptom improvement. Similary, improvement in functioning was also predicted by hgher novelty seeking and self-directedness after GVC, whereas better functioning was also associated with lower reward dependence and cooperativeness after surgery. CONCLUSIONS: The pattern of changes in personality traits after GVC was generally towards that observed in nonclinical population, and does not raise safety concerns.

Assessment of Safety and Outcome of Lateral Hypothalamic Deep Brain Stimulation for Obesity in a Small Series of Patients With Prader-Willi Syndrome.

Importance: Deep brain stimulation (DBS) has been investigated for treatment of morbid obesity with variable results. Patients with Prader-Willi syndrome (PWS) present with obesity that is often difficult to treat. Objective: To test the safety and study the outcome of DBS in patients with PWS. Design, Setting, and Participants: This case series was conducted in the Hospital das Clínicas, University of São Paulo, Brazil. Four patients with genetically confirmed PWS presenting with severe obesity were included. Exposure: Deep brain stimulation electrodes were bilaterally implanted in the lateral hypothalamic area. After DBS implantation, the treatment included the following phases: titration (1-2 months), stimulation off (2 months), low-frequency DBS (40 Hz; 1 month), washout (15 days), high-frequency DBS (130 Hz; 1 month), and long-term follow-up (6 months). Main Outcomes and Measures: Primary outcome measures were adverse events recorded during stimulation and long-term DBS treatment. Secondary outcomes consisted of changes in anthropometric measures (weight, body mass index [calculated as weight in kilograms divided by height in meters squared], and abdominal and neck circumference), bioimpedanciometry, and calorimetry after 6 months of treatment compared with baseline. The following evaluations and measurements were conducted before and after DBS: clinical, neurological, psychiatric, neuropsychological, anthropometry, calorimetry, blood workup, hormonal levels, and sleep studies. Adverse effects were monitored during all follow-up visits. Results: Four patients with PWS were included (2 male and 2 female; ages 18-28 years). Baseline mean (SD) body mass index was 39.6 (11.1). Two patients had previous bariatric surgery, and all presented with psychiatric comorbidity, which was well controlled with the use of medications. At 6 months after long-term DBS, patients had a mean 9.6% increase in weight, 5.8% increase in body mass index, 8.4% increase in abdominal circumference, 4.2% increase in neck circumference, 5.3% increase in the percentage of body fat, and 0% change in calorimetry compared with baseline. Also unchanged were hormonal levels and results of blood workup, sleep studies, and neuropsychological evaluations. Two patients developed stimulation-induced manic symptoms. Discontinuation of DBS controlled this symptom in 1 patient. The other required adjustments in medication dosage. Two infections were documented, 1 associated with skin picking. Conclusions and Relevance: Safety of lateral hypothalamic area stimulation was in the range of that demonstrated in patients with similar psychiatric conditions receiving DBS. In the small cohort of patients with PWS treated in our study, DBS was largely ineffective.

Visuospatial Memory Improvement after Gamma Ventral Capsulotomy in Treatment Refractory Obsessive-Compulsive Disorder Patients.

Gamma ventral capsulotomy (GVC) radiosurgery is intended to minimize side effects while maintaining the efficacy of traditional thermocoagulation techniques for the treatment of refractory obsessive-compulsive disorder (OCD). Neuropsychological outcomes are not clear based on previous studies and, therefore, we investigated the effects of GVC on cognitive and motor performance. A double-blind, randomized controlled trial (RCT) was conducted with 16 refractory OCD patients allocated to active treatment (n=8) and sham (n=8) groups. A comprehensive neuropsychological evaluation including intellectual functioning, attention, verbal and visuospatial learning and memory, visuospatial perception, inhibitory control, cognitive flexibility, and motor functioning was applied at baseline and one year after the procedure. Secondary analysis included all operated patients: eight from the active group, four from the sham group who were submitted to surgery after blind was broken, and five patients from a previous open pilot study (n=5), totaling 17 patients. In the RCT, visuospatial memory (VSM) performance significantly improved in the active group after GVC (p=0.008), and remained stable in the sham group. Considering all patients operated, there was no decline in cognitive or motor functioning after one year of follow-up. Our initial results after 1 year of follow-up suggests that GVC not only is a safe procedure in terms of neuropsychological functioning but in fact may actually improve certain neuropsychological domains, particularly VSM performance, in treatment refractory OCD patients.

Gamma ventral capsulotomy for obsessive-compulsive disorder: a randomized clinical trial.

IMPORTANCE: Select cases of intractable obsessive-compulsive disorder (OCD) have undergone neurosurgical ablation for more than half a century. However, to our knowledge, there have been no randomized clinical trials of such procedures for the treatment of any psychiatric disorder. OBJECTIVE: To determine the efficacy and safety of a radiosurgery (gamma ventral capsulotomy [GVC]) for intractable OCD. DESIGN, SETTING, AND PARTICIPANTS: In a double-blind, placebo-controlled, randomized clinical trial, 16 patients with intractable OCD were randomized to active (n = 8) or sham (n = 8) GVC. Blinding was maintained for 12 months. After unblinding, sham-group patients were offered active GVC. INTERVENTIONS: Patients randomized to active GVC had 2 distinct isocenters on each side irradiated at the ventral border of the anterior limb of the internal capsule. The patients randomized to sham GVC received simulated radiosurgery using the same equipment. MAIN OUTCOMES AND MEASURES: Scores on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Clinical Global Impression-Improvement (CGI-I) Scale. Response was defined as a 35% or greater reduction in Y-BOCS severity and "improved" or "much improved" CGI-I ratings. RESULTS: Three of 8 patients randomized to active treatment responded at 12 months, while none of the 8 sham-GVC patients responded (absolute risk reduction, 0.375; 95% CI, 0.04-0.71). At 12 months, OCD symptom improvement was significantly higher in the active-GVC group than in the sham group (Y-BOCS, P = .046; Dimensional Y-BOCS, P = .01). At 54 months, 2 additional patients in the active group had become responders. Of the 4 sham-GVC patients who later received active GVC, 2 responded by post-GVC month 12. The most serious adverse event was an asymptomatic radiation-induced cyst in 1 patient. CONCLUSIONS AND RELEVANCE: Gamma ventral capsulotomy benefitted patients with otherwise intractable OCD and thus appears to be an alternative to deep-brain stimulation in selected cases. Given the risks inherent in any psychiatric neurosurgery, such procedures should be conducted at specialized centers. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01004302.

Hoarding symptoms and prediction of poor response to limbic system surgery for treatment-refractory obsessive-compulsive disorder.

UNLABELLED: OBJECT.: Recent findings have suggested a correlation between obsessive-compulsive disorder (OCD) symptom dimensions and clinical outcome after limbic system surgery for treatment-refractory patients. Based on previous evidence that the hoarding dimension is associated with worse outcome in conventional treatments, and may have a neural substrate distinct from OCD, the authors examined a large sample of patients undergoing limbic surgery (40 with capsulotomy, 37 with cingulotomy) and investigated if symptom dimensions, in particular hoarding, could influence treatment outcome. METHODS: Data from 77 patients from 3 different research centers at São Paulo (n = 17), Boston (n = 37), and Stockholm (n = 23) were analyzed. Dimensional Yale-Brown Obsessive Compulsive Scale (Y-BOCS; São Paulo) or Y-BOCS Symptom Checklist scores (Boston and Stockholm) were used to code the presence of 4 well-established symptom dimensions: forbidden thoughts, contamination/cleaning, symmetry/order, and hoarding. Reductions in YBOCS scores determined clinical outcome. RESULTS: Mean Y-BOCS scores decreased 34.2% after surgery (95% CI 27.2%-41.3%), with a mean follow-up of 68.1 months. Patients with hoarding symptoms had a worse response to treatment (mean Y-BOCS decrease of 22.7% ± 25.9% vs 41.6% ± 32.2%, respectively; p = 0.006), with no significant effect of surgical modality (capsulotomy vs cingulotomy). Patients with forbidden thoughts apparently also had a worse response to treatment, but this effect was dependent upon the co-occurrence of the hoarding dimension. Only the negative influence of the hoarding dimension remained when an ANOVA model was performed, which also controlled for preoperative symptom severity. CONCLUSIONS: The presence of hoarding symptoms prior to surgery was associated with worse clinical outcome after the interventions. Patients with OCD under consideration for ablative surgery should be carefully screened for hoarding symptoms or comorbid hoarding disorder. For these patients, the potentially reduced benefits of surgery need to be carefully considered against potential risks.

Attention deficit/hyperactivity disorder: is there a correlation between dopamine transporter density and cerebral blood flow?

Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent behavioral problems in school-age children. Although the etiology remains unclear, the involvement of the dopaminergic system has been suggested by genetic studies that report an overexpression of the dopamine transporter (DAT) gene. In spite of these abnormalities being directly related to the decrease of dopamine (DA) in the striatum (STR), abnormalities in brain perfusion have also been observed in cortical-subcortical structures. Functional neuroimaging studies have suggested that the DA concentration may cause changes in the cerebral blood flow (CBF). The objective of our study was to evaluate the relationship between DAT density in STR and cortical-subcortical impairment in CBF. Based on the hypothesis that there is a correlation between DA availability and brain perfusion, we postulated that individuals with ADHD, with a higher DAT density in the basal ganglia, will have lower perfusion in the fronto-striatal-cerebellar networks. We used Tc-99m TRODAT-1 SPECT to measure DAT density and Tc-99m ECD SPECT to assess brain perfusion. Ten adolescents diagnosed with ADHD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria were investigated. Analysis with Statistical Parametric Mapping 5 corrected for multiple comparisons, using small volume correction, showed a significant negative correlation between the DAT density in the STR and CBF in the cingulate gyrus, frontal lobe, temporal lobe, and cerebellum (pFDR <0.01). Our findings suggest that higher DAT density in the STR was associated with a decrease in the regional CBF in the cortical and subcortical attention network.

Clinical and molecular neuroimaging characteristics of Brazilian patients with Parkinson's disease and mutations in PARK2 or PARK8 genes / Características clínicas e de neuroimagem molecular de pacientes brasileiros com doença de Parkinson e mutações nos genes PARK2 ou PARK8

OBJECTIVE: To describe clinical and neuroimaging (SPECT) characteristics of Brazilian patients with Parkinson's disease (PD) and mutations in PARK2 or PARK8 genes. METHOD: A total of 119 patients meeting clinical criteria for PD were evaluated. RESULTS: Of all patients studied, 13 had mutations in either PARK2 (n=9) or PARK8 genes (n=4). No statistically significant differences in clinical characteristics in both groups were seen. SPECT with [99mTc] TRODAT-1 showed significant differences between patient and control and the most remarkable difference was between PARK2 and control. CONCLUSION: The study found a frequency of mutation of 10.1 percent and it was most commonly seen in women. These patients had long disease course and high rates of dyskinesia after L-DOPA use. PARK8 patients did not have a relevant family history of PD.

OBJETIVO: Descrever as características clínicas e de neuroimagem (SPECT) de pacientes brasileiros com doença de Parkinson e mutações PARK2 e PARK8. MÉTODO: Foram avaliados 119 pacientes com critérios clínicos para a doença de Parkinson. RESULTADO: Entre os pacientes avaliados foram encontrados 13 pacientes com mutação nos genes PARK2 (n=9) ou PARK8 (n=4). Não houve diferença significativa na avaliação das características clínicas entre os dois grupos. Os resultados de SPECT mostraram diferenças significativas quanto ao potencial de ligação do [99mTc] TRODAT-1 SPECT entre pacientes vs. controle, sendo a diferença mais pronunciada entre PARK2 e controle. CONCLUSÃO: A freqüência de mutação encontrada foi 10,1 por cento, sendo mais comum em mulheres. Estes pacientes apresentavam longo tempo de doença e alta prevalência de discinesias associadas ao uso da levodopa. Nossos pacientes com PARK8 não apresentaram uma história familiar relevante de doença de Parkinson.

Dopamine transporter density by [99mTc]-TRODAT-1 SPECT and neurocognitive performance - a preliminary pilot study

Introducción: los déficits cognitivos están relacionados con el deterioro funcional y con la baja calidad de vida en la enfermedad de Parkinson (EP). El sistema dopaminérgico de los ganglios basales es importante para el funcionamiento cognitivo y motor. Radiomarcadores de transportador de Dopamina (TAD) han sido utilizados para calcular la pérdida neuronal dopaminérgica en humanos. Objetivos: estudiar la relación entre el deterioro cognitivo y la pérdida neuronal dopaminérgica estriatal en pacientes con EP. Métodos: quince pacientes fueron escaneados con [99mTc]-TRODAT-1 y SPECT. El estriado (STR) y el lóbulo occipital (BKG) fueron definidos como regiones de interés (RIs) para la obtención del potencial de ligación (PL = [STR - BKG] / BKG). Exámenes neurocognitivos fueron aplicados, incluyendo el Rey Auditory Verbal Learning Test (RAVLT), Wisconsin Card Sorting Test (WCST), Ravens Progressive Matrices, Digit Span y Tavis 3. Resultados: El PL fue correlacionado negativamente con los exámenes de RAVLT 4 y 5, que evalúan el aprendizaje verbal. El PL también fue correlacionado negativamente con el artículo de aprendizaje de WCST y los artículos de Tavis 3, el error de acción y el número de aciertos. Conclusiones: este estudio indica que la pérdida de TAD estriatal está asociada con un desempeño mas pobre en tareas de flexibilidad cognitiva y aprendizaje verbal. Estos resultados están de acuerdo con un estudio previo con participantes sanos que encontró una relación entre la densidad de TAD del caudado y el desempeño en tareas de aprendizaje verbal. La segmentación del caudado/putamen en una muestra mayor está en desarrollo y podrá proveer más información sobre déficits cognitivos y pérdida de TAD estriatal.