Objective: The aim of the present study was to analyze the body sway response in specific phobia (SP) patients and healthy controls while viewing neutral, phobic, and disgusting images. Methods: The participants’ heart rate (HR) and skin conductance were also recorded during the procedure. Nineteen patients with arachnophobia and 19 healthy volunteers matched by age, gender, and years of education underwent a postural control test on a stabilometric platform. Results: The platform recorded increased body sway in the SP group when exposed to spider images (SPI). The SP group presented increases in most parameters (SD, velocity, frequency, area, p ≤ 0.05) when viewing pictures of the SPI category. Psychometric measures of subjective anxiety (State-Trait Anxiety Inventory, STAI) and physiological states (HR; skin conductance responses; spontaneous fluctuations in skin conductance) showed increased anxiety (p ≤ 0.05) in the SP group compared to healthy volunteers. High anxiety levels were observed throughout the assessment, including the task of exposure to SPI (p ≤ 0.05). No significant effect or correlation was found between skin conductance and body sway measures (p > 0.05). Conclusions: The results of the postural control test suggest the occurrence of a defensive escape response in SP, in agreement with previous evidence.

A Fobia Específica (SP do inglês) é caracterizada por medos irracionais associados à evitação de estímulos específicos. Nos últimos anos, técnicas de neuroimagem vêm sendo empregadas na tentativa de melhor compreender a neurobiologia dos transtornos de ansiedade. O objetivo do presente estudo é realizar uma revisão sistemática dos artigos que utilizaram neuroimagem para estudar a SP. A busca na literatura foi realizada por intermédio de indexadores eletrônicos, utilizando-se as palavras-chave: imaging, neuroimaging, PET, spectroscopy, functional magnetic ressonance, structural magnetic ressonance, SPECT, MRI, DTI e tractography, cruzadas individualmente com os termos simple phobia e specific phobia. Foram encontrados 115 artigos, sendo 38 deles selecionados para a presente revisão. Desses, 24 usaram fMRI, 11 usaram PET, 1 usou SPECT, 2 usaram MRI estrutural e nenhum artigo de espectroscopia. Verifica-se que os estudos na área foram publicados recentemente e que, até o momento, o substrato neuroanatômico deste transtorno não está consolidado. Apesar das diferenças metodológicas entre os estudos, os resultados convergem para maior ativação na ínsula, cíngulo anterior, amídala e córtex préfrontal e orbitofrontal dos pacientes expostos a situações phobia related quando comparados aos controles. Esses achados reforçam hipóteses a respeito da hiperativação de uma determinada rede de estruturas neuroanatômicas envolvidas no transtorno de SP.

OBJECTIVE: Specific phobia (SP) is characterized by irrational fear associated with avoidance of specific stimuli. In recent years, neuroimaging techniques have been used in an attempt to better understand the neurobiology of anxiety disorders. The objective of this study was to perform a systematic review of articles that used neuroimaging techniques to study SP. METHOD:A literature search was conducted through electronic databases, using the keywords: imaging, neuroimaging, PET, spectroscopy, functional magnetic resonance, structural magnetic resonance, SPECT, MRI, DTI, and tractography, combined with simple phobia and specific phobia. One-hundred fifteen articles were found, of which 38 were selected for the present review. From these, 24 used fMRI, 11 used PET, 1 used SPECT, 2 used structural MRI, and none used spectroscopy. RESULT: The search showed that studies in this area were published recently and that the neuroanatomic substrate of SP has not yet been consolidated. CONCLUSION: In spite of methodological differences among studies, results converge to a greater activation in the insula, anterior cingulate cortex, amygdala, and prefrontal and orbitofrontal cortex of patients exposed to phobia-related situations compared to controls. These findings support the hypotheses of the hyperactivation of a neuroanatomic structural network involved in SP.