Olfactory evaluation in hospitalised and self-isolated patients with COVID-19: a single-centre experience on 55 cases.

BACKGROUND: Smell loss is a common symptom of COVID-19 infection. Majority of the studies that evaluated olfactory impairment in COVID-19 used questionnaires (subjective smell evaluations) and did not compare the results with objective or semiobjective measures of smell. We performed smell testing in hospitalised and self-isolated patients with COVID-19 and control participants. METHODS: Fifty-five COVID-19 and 44 control participants underwent smell testing, using Burghart Sniffin' Sticks 'Screening 12 Test'. Participants also rated their smelling capability on the numerical scale. Differences between groups and correlation between smell loss and time from acute onset of symptoms were tested, as well as correlation between results of smell test and subjective assessment of smell. RESULTS: Hospitalised patients with COVID-19 correctly determined 6.5/12 odorants compared with 10/12 in the self-isolated and 11/12 in the control group (p<0.001). Hyposmia or anosmia were present in 87.5% of hospitalised and 29.0% of self-isolated patients (p<0.001). The correlation between subjective self-assessment and results of smell testing was non-significant in both groups of patients with COVID-19, while there was a moderate positive correlation (p=0.001, Spearman's correlation coefficient=0.499) in control participants. CONCLUSION: Contrary to some previous reports suggesting that the presence of olfactory loss may predict milder course of disease, our study found that a vast majority of hospitalised patients with COVID-19 had prominent olfactory impairment. The absence of correlation between self-rated and objective smell evaluation in patients with COVID-19 indicates that subjective smell assessment is unreliable.

Bee Venom Does Not Reduce the Risk for Parkinson's Disease: Epidemiological Study among Beekeepers.

BACKGROUND: Based on the promising results from preclinical studies, bee venom has been investigated as a neuroprotective agent in Parkinson's disease. OBJECTIVE: To assess if longstanding exposure to bee venom is associated with decreased risk for Parkinson's disease among beekeepers. METHODS: Questionnaire gathering information about diagnosis of Parkinson's disease and exposure to bee stings was posted to 6500 members of Slovenian beekeepers' organisation. RESULTS: We received 1298 responses (response rate 20.1%). Twenty beekeepers, all older than 60 years, were diagnosed with Parkinson's disease. The prevalence of Parkinson's disease in beekeepers aged ≥60 years was 3.9%, which is above the reported 0.6-1.3% prevalence of PD in this age group in European population. There was no difference in parameters reflecting bee venom exposure between beekeepers with and without Parkinson's disease. CONCLUSIONS: Continuous exposure to bee venom does not affect neurodegeneration to the extent where it could prevent the expression of Parkinson's disease. © 2021 International Parkinson and Movement Disorder Society.

Auditory agnosia with anosognosia.

A 66-year-old right-handed female medical doctor suffered two consecutive cardioembolic strokes, initially affecting the right frontal lobe and the right insula, followed by a lesion in the left temporal lobe. The patient presented with distinctive phenomenology of general auditory agnosia with anosognosia for the deficit. She did not understand verbal requests and her answers to oral questions were fluent but unrelated to the topic. However, she was able to correctly answer written questions, name objects, and fluently describe their purpose, which is characteristic for verbal auditory agnosia. She was also unable to recognise environmental sounds or to recognise and repeat any melody. These inabilities represent environmental sound agnosia and amusia, respectively. Surprisingly, she was not aware of the problem, not asking any questions regarding her symptoms, and avoiding discussing her inability to understand spoken language, which is indicative of anosognosia. The deficits in our patient followed a distinct pattern of recovery. The verbal auditory agnosia was the first to resolve, followed by environmental sound agnosia. Amusia persisted the longest. The patient was clinically assessed from the first day of symptom onset and the evolution of symptoms was video documented. We give a detailed account of the patient's behaviour and provide results of audiological and neuropsychological evaluations. We discuss the anatomy of auditory agnosia and anosognosia relevant to the case. This case study may serve to better understand auditory agnosia in clinical settings. It is important to distinguish auditory agnosia from Wernicke's aphasia, because use of written language may enable normal communication.

Central nystagmus in progressive supranuclear palsy: A neglected clinical feature?

BACKGROUND: Progressive supranuclear palsy (PSP) features parkinsonism characterized by early postural instability, falls and prominent eye movement abnormalities that consist of saccadic slowing, followed by gaze limitation. Nystagmus is not considered typical for PSP, being more commonly associated with multiple system atrophy. OBJECTIVES: To describe the prevalence and phenomenology of nystagmus in patients with PSP. METHODS: 42 patients with probable PSP underwent detailed clinical eye movement examination. Patients with nystagmus performed video-nystagmography. T-test, Chi-Square test and Wilcoxon signed-rank test were used to test differences in demographic data, disease duration and PSP subtype between patients with and without nystagmus, and for analysis of video-nystagmographic data. RESULTS: Among 42 patients with PSP, we identified 15 patients (35,7%) with gaze-evoked nystagmus, predominantly horizontal. Clinically, 10/15 patients had symmetrical or asymmetrical gaze - evoked nystagmus (Type 1), while 5/15 patients had dissociated gaze-evoked nystagmus related to internuclear ophthalmoplegia (Type 2). Nystagmus and eye movement abnormalities were further characterized by video-nystagmography. There was no significant difference in age, disease duration or PSP subtypes between patients with and without nystagmus. CONCLUSION: Central nystagmus is present in more than a third of patients with progressive supranuclear palsy. It may present as symmetrical or asymmetrical gaze-evoked nystagmus or as dissociated gaze-evoked nystagmus related to internuclear ophthalmoplegia and probably arises from neurodegeneration of the neural integrator. Nystagmus in PSP has been a hitherto under-described feature and its presence should not deter clinicians from a diagnosis of PSP.

Deep brain stimulation and eye movements.

Deep brain stimulation (DBS) has been most widely used in the management of movement disorders, but more recently to treat a growing number of neurological and psychiatric conditions. It is know to have a variety of effects upon oculomotor function, depending not only on the location of the stimulation, but also the underlying pathology being treated. Understanding how DBS affects eye movements is important, given the widespread nature of eye movement control and its inevitable overlap with many of the networks targeted by the stimulation. Moreover, it can also offer additional mechanistic insights into neural circuits involved in complex eye movement control. Here, we discuss the application of DBS treatment across different diseases and explore how distinct stimulation locations interfere with known eye movement circuits and the ensuing oculomotor and visual effects it can produce. We also discuss more experimental DBS targets and its effects on ocular motility, as well as discussing unilateral versus bilateral deep brain stimulation and possible hemispheric asymmetry in relation to eye movement control. Contradictory findings across studies reporting DBS effects on eye movements likely relate to differences in the methodological approaches used, levodopa medication status, as well as possible variability in DBS electrode placement. We highlight the need for further research with less common DBS targets on the possible effects upon eye movements.