Anosmia and Ageusia in Parkinson's Disease

Tarakad, Arjun; Jankovic, Joseph

doi:10.1016/bs.irn.2017.05.028

Cited by 76 publications

(66 citation statements)

References 71 publications

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“…In fact, cholinergic denervation of the limbic archicortex (assessed through [(11)C]methyl-4-piperidinyl propionate acetylcholinesterase brain positron emission tomography) was found to be a more robust determinant of hyposmia than nigrostriatal dopaminergic denervation in patients with moderately severe PD without dementia (Bohnen et al, 2010). These data are in line with the observation that hyposmia does not improve with levodopa (Tarakad and Jankovic, 2017), while some evidences suggest that rasagiline is associated with significantly better odor discrimination abilities in early-PD patients (Haehner et al, 2015).…”

Section: Smell and Pdsupporting

confidence: 74%

“Smelling and Tasting” Parkinson's Disease: Using Senses to Improve the Knowledge of the Disease

Oppo

Melis

et al. 2020

Front. Aging Neurosci.

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Among non-motor manifestations of Parkinson's Disease (PD), peripheral, sensory symptoms are particularly relevant. Smell dysfunction starts very early and frequently precedes the PD motor symptoms by years (being often a cue to the diagnosis). Moreover, olfactory system could be, together with gut, one of those peripheral sites where PD pathology first develops. Unlike smell loss, the relationship between PD and taste impairment is far less established. It can start early in the course of the disease but more frequently appears in advanced stages, in parallel with the advent of MCI, likely reflecting cortical involvement. Among PD patients has been demonstrated an increase in the frequency of the non-tasters for PROP (prototypical gustatory stimulus, 6-n-propylthiouracil), a genetically determined bitter taste which is mediated by TAS2RS38 receptor, and a significant increase of the recessive non-testing variant of this receptor. TAS2R38 receptors are expressed also in other tissues, such as in the epithelia of the gut and nasal cavities, where they can influence epithelial immunity ad its interaction with microbiota. Those pieces of evidence suggest that not only systematic assessment of taste and smell can be of a remarkable help for clinicians in the early diagnosis, but also that understanding the mechanisms of sensory involvement in PD could increase the knowledge of the pathophysiology of the disease.

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Section: Smell and Pdsupporting

confidence: 74%

“Smelling and Tasting” Parkinson's Disease: Using Senses to Improve the Knowledge of the Disease

Oppo

Melis

et al. 2020

Front. Aging Neurosci.

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“…However, non-motor symptoms can precede motor symptoms by more than a decade 2 and include olfactory dysfunction, rapid eye movement sleep behaviour disorder and autonomic disorders such as constipation. The non-motor symptoms and motor symptoms appear to coincide with the aggregation of the pathological protein α-synuclein (α-syn) in specific brain regions [2][3][4] . Phosphorylated α-syn pathology affects different brain regions in a sequential pattern that has been characterised into six stages 5 .…”

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confidence: 99%

α-synuclein inclusions are abundant in non-neuronal cells in the anterior olfactory nucleus of the Parkinson’s disease olfactory bulb

Stevenson

Murray

Turner

et al. 2020

Sci Rep

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Reduced olfactory function (hyposmia) is one of the most common non-motor symptoms experienced by those living with Parkinson's disease (PD), however, the underlying pathology of the dysfunction is unclear. Recent evidence indicates that α-synuclein (α-syn) pathology accumulates in the anterior olfactory nucleus of the olfactory bulb years before the motor symptoms are present. it is well established that neuronal cells in the olfactory bulb are affected by α-syn, but the involvement of other non-neuronal cell types is unknown. the occurrence of intracellular α-syn inclusions were quantified in four non-neuronal cell types-microglia, pericytes, astrocytes and oligodendrocytes as well as neurons in the anterior olfactory nucleus of post-mortem human pD olfactory bulbs (n = 11) and normal olfactory bulbs (n = 11). In the anterior olfactory nucleus, α-syn inclusions were confirmed to be intracellular in three of the four non-neuronal cell types, where 7.78% of microglia, 3.14% of pericytes and 1.97% of astrocytes were affected. Neurons containing α-syn inclusions comprised 8.60% of the total neuron population. oligodendrocytes did not contain α-syn. the data provides evidence that non-neuronal cells in the pD olfactory bulb contain α-syn inclusions, suggesting that they may play an important role in the progression of pD.

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“…It is well known that anosmia and ageusia are common nonmotor features of PD. 6 So, it is possible that the episode of a/hyposmia and a/hypogeusia during the COVID-19 is a small "hit" for the development of parkinsonian symptoms in the future. Perhaps physicians should soon, when examining a patient with suspected PD, clarify the fact of a/hyposmia and a/hypogeusia during the COVID-19 epidemic.…”

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confidence: 99%

A Post‐COVID‐19 Parkinsonism in the Future?

Boika

2020

Movement Disorders

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Now, almost all countries of the world live in conditions of an ongoing viral pandemic attributed to the coronavirus disease 2019 . The contact of humankind with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will have both immediate and long-term consequences not only for medicine and economics, but also for culture, politics, etc. Given the fact that symptoms of COVID-19 include a/hyposmia and a/hypogeusia, we should consider how this infection will affect the incidence of Parkinson's disease (PD; and/or other neurodegenerative diseases).I performed a literature review (utilizing PubMed and Google Scholar) focusing on neurological complications of influenza. There are few publications which report on the development of neurological symptoms relating to PD (especially tremor and gait disturbance) within a month after the influenza. 1,2 However, we currently do not have information that the risk of PD development is associated with previous acute viral respiratory infections. 1 But, it is well known that the pathogenesis of PD is extended over time, and it is not possible to accurately determine the first, asymptomatic stage of PD. At this time, the stage-by-stage theory of sporadic PD development made by Heiko Braak and his colleagues is popular. In their theory, the agent penetrates into the nervous system through the nose or gastrointestinal system and results in an abnormal accumulation of the protein, alpha-synuclein, bound to ubiquitin in the damaged cells. 3 So, the development of parkinsonian symptoms after viral respiratory diseases allows us to take a fresh look at the etiology and pathogenesis of PD. It is worth drawing a historical parallel with the postencephalitic lethargica parkinsonism that took place in the 1920s. The cause of the delayed development and progression of parkinsonian symptoms after the acute stage of encephalitis is still unknown. 4 Regarding PD, it is difficult to prove a causal relationship between influenza in the past and the development of parkinsonian symptoms because of the large number of years separating these events. It is possible that the development of PD can go according to the theory of "hit and run," 2,5 as a result of numerous small "hits" (which may include viral respiratory infections) that occur throughout life. It is well known that anosmia and ageusia are common nonmotor features of PD. 6 So, it is possible that the episode of a/hyposmia and a/hypogeusia during the COVID-19 is a small "hit" for the development of parkinsonian symptoms in the future. Perhaps physicians should soon, when examining a patient with suspected PD, clarify the fact of a/hyposmia and a/hypogeusia during the COVID-19 epidemic.So, to date, there are few publications about symptoms of parkinsonism associated with a pandemic of respiratory viruses. Undoubtedly, additional studies are needed to confirm/ refute the trigger effect of SARS-CoV-2 on the neuroinflammatory and -degenerative processes leading to the development of parkinsonian symptoms.

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Anosmia and Ageusia in Parkinson's Disease

Cited by 76 publications

References 71 publications

“Smelling and Tasting” Parkinson's Disease: Using Senses to Improve the Knowledge of the Disease

“Smelling and Tasting” Parkinson's Disease: Using Senses to Improve the Knowledge of the Disease

α-synuclein inclusions are abundant in non-neuronal cells in the anterior olfactory nucleus of the Parkinson’s disease olfactory bulb

A Post‐COVID‐19 Parkinsonism in the Future?

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