Difficulties of olfactometric evaluation in patients accusing smell disorders after head trauma

2018 ◽  
Vol 8 (29) ◽  
pp. 39-45
Author(s):  
Gabriela-Violeta Melinte ◽  
Codrut Sarafoleanu

Abstract Head trauma is considered to be the third cause of olfactory function disorders. Olfactometric assessment in patients accusing anosmia following head injury produced by car accident or aggression is important, because most of them are involved in law trials in order to obtain financial compensations from the author. It is compulsory to use both subjective and objective olfactory evaluation methods combined with a detailed anamnesis, a complete ENT examination and a good cranio-facial imaging (computed tomography or MRI) in order to exclude malingerers and to obtain an accurate diagnosis. “Sfanta Maria” ENT Department from Bucharest is the only center in Romania where the olfactory function in completely investigated. We use chemosensory (Snap and Sniff Test and n-Butanol Dynamic Olfactometry) and electrophysiological tests (electric olfactory evoked potentials of the olfactory bulb). Unfortunately, we confront with a series of difficulties in what concerns the smell function evaluation: 1) there is scarce information in the literature regarding the olfactory electric evoked potentials; 2) the electric olfactory evoked potentials register only the electrical activity in the olfactory bulb; 3) in case of olfactory impairment medically confirmed, we cannot establish a cause-effect relationship between the disturbance and the event; 4) the most accurate electrophysiological assessment method currently available in Europe is the time-frequency analysis of chemosensory event-related potentials, but we do not dispose of the necessary equipment yet; 5) sometimes patients do not give us the informed consent for a complete olfactory evaluation.

2007 ◽  
Vol 21 (5) ◽  
pp. 548-550 ◽  
Author(s):  
Philippe Rombaux ◽  
André Mouraux ◽  
Bernard Bertrand ◽  
Thierry Duprez ◽  
Thomas Hummel

Background Lack of an olfactory bulb (OB) is typically associated with anosmia. Methods We present a patient with subnormal olfactory function in whom the OB could not be detected with magnetic resonance imaging (MRI). Results Olfactory function was evaluated on two occasions. Orthonasal olfactory function was assessed with the “Sniffin’ Sticks” test providing a score equivalent to hyposmia. Retronasal olfactory function was studied with “smell powders” indicating a decreased, but not absence of, olfactory function. Importantly, chemosensory event-related potentials were clearly present in response to olfactory and trigeminal stimuli. Conclusion This indicates that olfactory function may be present in some subjects even when an OB can not be detected with MRI.


2015 ◽  
Vol 27 (5) ◽  
pp. 1017-1028 ◽  
Author(s):  
Paul Metzner ◽  
Titus von der Malsburg ◽  
Shravan Vasishth ◽  
Frank Rösler

Recent research has shown that brain potentials time-locked to fixations in natural reading can be similar to brain potentials recorded during rapid serial visual presentation (RSVP). We attempted two replications of Hagoort, Hald, Bastiaansen, and Petersson [Hagoort, P., Hald, L., Bastiaansen, M., & Petersson, K. M. Integration of word meaning and world knowledge in language comprehension. Science, 304, 438–441, 2004] to determine whether this correspondence also holds for oscillatory brain responses. Hagoort et al. reported an N400 effect and synchronization in the theta and gamma range following world knowledge violations. Our first experiment (n = 32) used RSVP and replicated both the N400 effect in the ERPs and the power increase in the theta range in the time–frequency domain. In the second experiment (n = 49), participants read the same materials freely while their eye movements and their EEG were monitored. First fixation durations, gaze durations, and regression rates were increased, and the ERP showed an N400 effect. An analysis of time–frequency representations showed synchronization in the delta range (1–3 Hz) and desynchronization in the upper alpha range (11–13 Hz) but no theta or gamma effects. The results suggest that oscillatory EEG changes elicited by world knowledge violations are different in natural reading and RSVP. This may reflect differences in how representations are constructed and retrieved from memory in the two presentation modes.


CoDAS ◽  
2021 ◽  
Vol 33 (2) ◽  
Author(s):  
Mariana Keiko Kamita ◽  
Liliane Aparecida Fagundes Silva ◽  
Carla Gentile Matas

RESUMO Objetivo Identificar e analisar quais são os achados característicos dos Potenciais Evocados Auditivos Corticais (PEAC) em crianças e/ou adolescentes com Transtorno do Espectro do Autismo (TEA) em comparação do desenvolvimento típico, por meio de uma revisão sistemática da literatura. Estratégia de pesquisa Após formulação da pergunta de pesquisa, foi realizada uma revisão da literatura em sete bases de dados (Web of Science, Pubmed, Cochrane Library, Lilacs, Scielo, Science Direct, e Google acadêmico), com os seguintes descritores: transtorno do espectro autista (autism spectrum disorder), transtorno autístico (autistic disorder), potenciais evocados auditivos (evoked potentials, auditory), potencial evocado P300 (event related potentials, P300) e criança (child). A presente revisão foi cadastrada no Próspero, sob número 118751. Critérios de seleção Foram selecionados estudos publicados na integra, sem limitação de idioma, entre 2007 e 2019. Análise dos dados: Foram analisadas as características de latência e amplitude dos componentes P1, N1, P2, N2 e P3 presentes nos PEAC. Resultados Foram localizados 193 estudos; contudo 15 estudos contemplaram os critérios de inclusão. Embora não tenha sido possível identificar um padrão de resposta para os componentes P1, N1, P2, N2 e P3, os resultados da maioria dos estudos demonstraram que indivíduos com TEA podem apresentar diminuição de amplitude e aumento de latência do componente P3. Conclusão Indivíduos com TEA podem apresentar respostas diversas para os componentes dos PEAC, sendo que a diminuição de amplitude e aumento de latência do componente P3 foram as características mais comuns.


2019 ◽  
Vol 12 ◽  
Author(s):  
Carlos Trenado ◽  
Anaí González-Ramírez ◽  
Victoria Lizárraga-Cortés ◽  
Nicole Pedroarena Leal ◽  
Elias Manjarrez ◽  
...  

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