INTRODUCTION: We report a case series two patients of Guillain-Barré syndrome (GBS) associated with previous COVID-19 that both patients survived. GBS is an immune-mediated disease that affects peripheral nerves and can cause life-threatening complications. CASE REPORTS: In both cases (53-year-old female and 59-year-old male) with severe GBS with complications, the smell of sense was investigated subjectively using Sniffin' sticks identification tests and objectively using objective olfactometry by the evaluation of olfactory event-related potentials (OERPs). Both patients had good results of the subjective Sniffin' sticks identification test without patholgical findings. Results of objective examination of OERPs: the P2-N1 wave complex was equipotent. No olfactory disturbance could be detected in either case, OERPs were plentiful in both cases. CONCLUSION: The presentation of a case series two patients of post-covid GBS are an example of one of the many complications of COVID-19 that can cause prolonged recovery. Despite the severe course of GBS and the long recovery time, both patients returned to normal life. An expanded prospective study is planned for the future to investigate post-covid olfactory impairment. The prevalence of GBS associated with COVID-19 is still unknown but it is evident that both mild and severe forms of GBS have been described in patients.

• Klíčová slova
• COVID-19 infection, Guillain-Barré syndrome, Sniffin stick tests, objective olfactometry, olfactory event-related potentials,
• MeSH
• Betacoronavirus MeSH
• čich fyziologie   MeSH
• COVID-19 * komplikace   patofyziologie   MeSH
• evokované potenciály * fyziologie   MeSH
• Guillainův-Barrého syndrom * patofyziologie   diagnóza   MeSH
• koronavirové infekce komplikace   patofyziologie   diagnóza   MeSH
• lidé středního věku MeSH
• lidé MeSH
• pandemie MeSH
• poruchy čichu etiologie   patofyziologie   diagnóza   MeSH
• SARS-CoV-2 * MeSH
• virová pneumonie komplikace   patofyziologie   diagnóza   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

INTRODUCTION: In recent years, the evaluation of potential events related to olfactory events (OERPs) and trigeminal events (TERPs) has become increasingly important in the diagnosis of olfactory disorders. This technique is increasingly used in basic research and clinical practice to evaluate people suffering from olfactory disorders. PURPOSE OF THE STUDY: In a pilot project of the first investigations of OERPs and TERPs in the Czech Republic, we analyse the event-related potentials of the data of normosmic participants. METHODS: In the prospective study, 21 normosmic participants were enrolled for a 2-year period (5/2021-5/2023). OERPs/TERPs were recorded at the scalp vertex (electrode Pz/Cz). Odourants 2-phenylethanol/CO2 were used to selectively activate Nervus olfactorius/ Nervus trigeminus. Brain responses to olfactory/trigeminal stimuli (EEG) were recorded in 21/18 normosmic subjects. RESULTS: In the statistical analysis of the olfactory interval N1-P2 (age, gender), we found no statistically significant differences. In the statistical analysis of the trigeminal interval N1-P2 (age, gender) we found statistically significant differences in amplitude by gender (male amplitudes were higher than female amplitudes, p = 0.006). CONCLUSION: Our pilot data can function very well as an internal guide for ongoing and future olfactory research studies. Evaluation of the presence of OERPs appears to be an important parameter for the evaluation of olfactory disorders. The absence of OERPs is a strong indicator of the presence of olfactory dysfunction.

• Klíčová slova
• Evaluation of smell, Objective olfactometry, Odourants, Olfactory event-related potentials, Trigeminal event-related potentials,
• MeSH
• čich * fyziologie   MeSH
• evokované potenciály fyziologie   MeSH
• lidé MeSH
• pilotní projekty MeSH
• poruchy čichu * diagnóza   MeSH
• prospektivní studie MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

The subjective and demanding nature of olfactory testing means that it is often neglected in clinic despite loss of smell leading to significant limitations in everyday life. The list of diseases associated with loss of olfaction far exceeds the field of otorhinolaryngology and can also be seen in neurodegenerative disorders. Knowledge of possible clinical testing is essential to determine a proper differential diagnosis for the loss of olfactory sense. Causes of olfactory impairment can be divided into either failure in transferring odour to the organ of perception or damage to the olfactory pathway structure itself. Examination should therefore include methods evaluating cross-sectional area and patency of the nasal cavity as well as subjective or objective assessment of olfactory function. In this report we summarize several articles, studies, and our own experiences to provide a comprehensive review of their current clinical usage including their benefits, limitations, and possible outcomes. We also discuss the mechanism of olfaction step by step to provide a full understanding of the possible errors depending on the localization in the pathway and the methods designed for their detection. We discuss the correlation of the microbiome in nasal polyposis and chronic rhinitis with olfactory impairment using objective olfactometry. The topic of objective olfactometry and the examination of olfactory event-related potentials (OERP) is commented upon in detail.

• Klíčová slova
• anosmia, hyposmia, objective olfactometry, odourants, olfactory event-related potentials, olfactory system, parosmia,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH