Evaluación de funciones cognitivas: atención y memoria en pacientes con trastorno de pánico / Cognitive function evaluation: attention and memory in panic disorder patients

ABSTRACT

Evidence from recent studies about the epidemiology of panic disorder (PD) indicates that it is present in 4.7% of general population. In Mexico City, 2.9% of females and 1.9% of males are affected by this disease. Due to the incidence cited above, it is considered an important mental health problem that has impacted social, labor and familiar areas. On the other hand, PD is frequently present in comorbidity with other disorders like major depression, social phobia and generalized anxiety disorder. Moreover, in some cases, it may lead to a suicide risk. PD is characterized by recurrent, unexpected panic attacks, and is commonly associated with agoraphobia. A panic attack is defined as a discrete period of fear or discomfort that includes physical, cognitive and behavioral symptoms. Physical symptoms comprise short breath, palpitations, sweating, dizziness, gastrointestinal discomfort, and chest pain. Cognitive symptoms are associated with catastrophic interpretation of bodily sensations; behavioral symptoms are mainly avoidant of different places, situations and actions that patient had associated with fear of loss of control. In the past few years there has been a growing interest in the neuropsychology of anxiety disorders. Neuropsychological evaluation is relevant because it implies an objective assessment of the cognitive and behavioral abilities and weaknesses that make possible the prediction of the course of the disorder and the effects of treatment modalities. One of the most important contributions of neuropsychological evaluation is the identification of stable patterns of cognitive profiles of a specific disorder considered as neurocognitive endophenotypes. Some recent studies have demonstrated the relationship between neuropsychological alterations and anxiety; nevertheless, most of them were observed in obsessive-compulsive disorder patients. On the other hand, studies examining neuropsychological functioning in PD patients are scarce and report conflicting results. The main objective of the present study was to evaluate whether PD patients with and without agoraphobia, who attended the National Institute of Psychiatry <Mexico City, showed neuropsychological impairments relative to healthy controls in attention, memory and executive functions. We studied a total sample of 48 subjects (24 patients with PD, the patients sample was selected according to a psychiatric evaluation, based on DSM-IV-TR criteria. Inclusion criteria were age between 19 and 56, men or women, without previous pharmacological or psychotherapeutically treatment; and 24 gender, age and education matched healthy control subjects). A neuropsychological test battery (Neuropsi Attention and Memory) in Spanish with norms by age and educational level was administered. The Neuropsi assesses orientation, attention and concentration, executive functions, working memory and immediate and delayed verbal and visual memory. Likewise, all patients were assessed with the Anxiety Sensitivity Index, Beck's Anxiety Inventory and Panic Disorder Severity Scale. According to this psychometric evaluation, the PD patients showed severe anxiety, high anxiety sensitivity, as well as a severe degree of panic symptoms. The differences between PD patients and control subjects in neuropsychological performance were determined through one way analysis of variance (p<0.05) with the assistance of the SPSS 12. The results of the present study indicate that the neuropsychological test performance of patients with PD is diminished relative to that of the health control. According to obtained results, there were significant differences in the total score of executive functions and attention, memory and global attention and memory between patients and healthy controls. In the analysis of different subscales, it was found that patients had reduced performance in visual search, digit backward span, world list free recall, Rey-Ostereith Complex Figure Test encoding and retrieval, word list cued recall, faces retrieval and in diverse executive functions like category formation test, semantic and phonological verbal fluency, as well as design fluency. This suggests that PD is associated with alterations in tasks that require flexibility in the mental processes, short-term memory, working memory, and in the generation of strategies to solve problems. However, it is possible that these alterations were present before the onset of panic disorder and predispose the ulterior development of this disorder. In the visual detection subscale, that evaluates selective attention, there were also differences in latency of response because patients were slower than healthy controls trying to find the correct figure. This deficiency is associated with the difficulty of PD patients to perceive important details of the environment due to the extreme attention in the corporal sensations. Besides, no group differences were found in orientation, attention and concentration. These findings are consistent with previous studies with PD patients, where impairments in verbal memory, executive functions and visuospatial memory were found. Nevertheless, these findings differ from the reported by others studies, where neuropsychological alterations in PD patients were found. These discrepancies could be due to methodological procedures in the sample selection, pharmacological treatment, intensity of anxiety, and the use of different neuropsychological instruments. In the present study, the clinical sample was characterized by absence of pharmacological and psychotherapeutic treatments before neuropsychological evaluation was done with the Neuropsi. A notable finding was that, in the face recognition subscale, patients had better scores than controls. This can be related to a previous reported finding, which suggested that PD patients pay more attention to the details of a face to evaluate if these are safe or unsafe before the possibility of having a panic attack. Also, it is possible to consider it like an special ability developed by these patients as a compensatory behavior before the disability caused by this disorder and the vulnerability they experience when not having control of their symptoms. In conclusion, we have demonstrated deficits in the visuospatial and verbal memory, and executive functions in PD patients. This finding supported a disturbance in the amygdaline fronto-temporal neural network in the disorder, related in the conditioned fear network involved in the etiology of panic disorder. Future neuropsychological studies will benefit from use of neuroimaging studies to examine pattern of brain activation and elucidate the pathophysiology features of the disorder. As well as determine whether cognitive performance varies as a function of severity of panic symptoms.

RESUMEN

De acuerdo a Kessler, el 4.7% de la población general presenta Trastorno de Pánico (TP) a lo largo de la vida, específicamente en la Ciudad de México el TP tiene una prevalencia en la vida de 1.1% en los hombres y de 2.5% en las mujeres, por lo que se considera un problema de gran relevancia. Aunado a esto, uno de los grandes problemas de este padecimiento es el alto índice de comorbilidad que presenta con otros trastornos psiquiátricos como la depresión mayor, la fobia social, el trastorno por ansiedad generalizada y el abuso de sustancias. De acuerdo con el DSM-IV-TR, el TP se caracteriza por la aparición de crisis de angustia inesperadas y recurrentes, inquietud persistente por la posibilidad de tener más crisis, preocupación por las implicaciones de las mismas o sus consecuencias y/o un cambio significativo del comportamiento relacionado con ellas. La evaluación neuropsicológica es relevante, ya que a través de ésta es posible obtener una valoración objetiva que permite conocer las habilidades y déficits cognoscitivos y conductuales de los pacientes con trastornos psiquiátricos para hacer una predicción sobre el curso de la enfermedad, elegir el tipo de tratamiento de forma objetiva, identificar patrones estables de déficits neuropsicológicos así como establecer estrategias que mejoren el pronóstico del trastorno. Diversos estudios han demostrado recientemente la relación entre algunas alteraciones neuropsicológicas y la ansiedad; sin embargo, la mayoría de éstos se han centrado en el trastorno obsesivo-compulsivo. Aunado a esto, los resultados encontrados en investigaciones que han evaluado las funciones cognitivas en el TP, no han sido consistentes. El objetivo del presente estudio fue determinar si existen déficits neuropsicológicos en pacientes diagnosticados con TP con o sin agorafobia que acudieron al servicio de preconsulta del Instituto Nacional de Psiquiatría Ramón de la Fuente, en comparación con sujetos control en los dominios de atención, memoria y funciones ejecutivas. Se seleccionaron dos grupos uno de 24 sujetos diagnosticados con TP, de acuerdo al DSM-IV-TR, sin tratamiento farmacológico y/o psicoterapéutico previo; y otro de 24 sujetos sanos comparados formando pares por sexo, edad y escolaridad con el primero. Se les aplicó una batería neuropsicológica (Neuropsi Atención y Memoria) que evalúa orientación, atención y concentración, memoria de trabajo, memoria verbal y visual, y funciones ejecutivas y motoras. El Neuropsi Atención y Memoria cuenta con normas obtenidas en la población mexicana, considerando la edad y la escolaridad. Las diferencias en el desempeño cognitivo entre el grupo control y el grupo con TP fueron analizadas por medio de un Análisis de Varianza (con p<0.05). Los resultados mostraron que los sujetos con TP puntuaron significativamente más bajo que los controles en el puntaje total de atención y memoria, en el puntaje del total de atención y funciones ejecutivas, y el total de memoria. El análisis de las subpruebas específicas reveló déficits en la memoria verbal, la memoria visoespacial inmediata y la evocada, y en diversas funciones ejecutivas formación de categorías, fluidez verbal semántica y fonológica, y fluidez no verbal. Los hallazgos encontrados en este estudio apoyan la noción de que la ansiedad (específicamente el TP) afecta la memoria verbal y la visoespacial así como las funciones ejecutivas. Los pacientes con TP mostraron alteraciones significativas en tareas que requieren de la capacidad de cambiar de foco de atención, flexibilidad en los procesos cognitivos, capacidad de inhibir respuestas inadecuadas, memoria a corto plazo y memoria de trabajo.