Author ORCID Identifier
Advisor Information
Dr. Bruce Chase
Location
Room 225
Presentation Type
Oral Presentation
Start Date
1-3-2019 12:45 PM
End Date
1-3-2019 2:00 PM
Abstract
Parkinson’s disease (PD) is a progressive, incurable neurodegenerative disease thatcauses slowness, rigidity, and postural instability but which also has many non-motor manifestations. One of these is olfactory dysfunction, which has been found to occur in at least 90% of patients diagnosedwith Parkinson’s disease (Doty et al., 1988). This deficit tends to appear early in the onset of the disease and is even thought to appear before motor dysfunction (Haehner, Hummel, & Reichmann, 2009; Ross et al., 2008; Doty, 2012). Thus, olfaction is being assessed as one of a set of possible predictors for of the disease (Ponsen, Stoffers, Twisk, Wolters, & Berendse, 2009). Diagnosis of PD is difficult, even in specialty clinics (Jankovic, 2008). Early diagnosis could have a large impact on the quality of life of an individual because if they are diagnosed before the onset of motor symptoms, they will have more time to plan and consider different treatment options. Early detection could also aid physicians treating the patient as it would allow them more time to assess proper intervention methods that may slow, halt, or reverse the course of the disease. Olfactory deficits are also thought to predict later cognitive dysfunction in PD (Duda, Chahine, & Morley, 2016) and in Alzheimer disease, which is primarily marked by cognitive dysfunction, nearly all patients have severe olfactory deficits (Zou et al., 2016).
While olfactory dysfunction can be evaluated using different methods (Doty, 2015), one of the most widely used assessment tools is the University of Pennsylvania Smell Identification Test (UPSIT). The UPSIT has high test-retest reliability and well-established norms for age and sex (Doty et al., 1984). It is a forced-choice, scratch-and-sniff test that evaluates 40 microencapsulated odors. After a pencil scratch releases an odor, the subject is asked to identify the odor from four verbally stated options. Each correctly recognized odor results in one point, so subjects able to correctly identify all odors receive a score of 40. While the UPSIT is widely used to access olfactory deficit, it also contains a potential confound. Lower UPSIT scores could be attributed to cognitive impairment if the subject is unable to remember the odor presented, remember all the possible verbally administered answers, or cannot reliably process odor information. If cognitive deficits, not the inability to smell, are driving low UPSIT scores, subjects taking the test at different times might get similar scores, but misidentify different odors. Indeed, this was reported by Markopoulou et al. (2016) for both PD and age-matched control subjects with modest olfactory dysfunction.
Characterizing how potentially subtle cognitive impairments impact olfactory dysfunction has the potential to influence how olfactory tests are used to aid in diagnosis of neurodegenerative diseases. If subtle cognitive impairments impact measurement of olfactory dysfunction, then assessment for such cognitive impairments might be a more sensitive measure in predicting incipient motor symptoms of PD than olfactory-based measurements of olfactory dysfunction. If so, that could precede or replace assessment of olfactory dysfunction. We already know, however, that standard quick tests for cognitive impairment that are used clinically, such as the Montreal Cognitive Assessment (MoCA), (Hoops et al., 2009) cannot be used to explain the cognitive processes that may underlie the lack of odor-identification reproducibility seen in those with PD. The aim of this research is to evaluate whether subtle cognitive deficits impact olfactory function scores and thereby impact the assessment of olfactory dysfunction.
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The Possible Cognitive Confound in Olfactory Testing for Parkinson’s Disease
Room 225
Parkinson’s disease (PD) is a progressive, incurable neurodegenerative disease thatcauses slowness, rigidity, and postural instability but which also has many non-motor manifestations. One of these is olfactory dysfunction, which has been found to occur in at least 90% of patients diagnosedwith Parkinson’s disease (Doty et al., 1988). This deficit tends to appear early in the onset of the disease and is even thought to appear before motor dysfunction (Haehner, Hummel, & Reichmann, 2009; Ross et al., 2008; Doty, 2012). Thus, olfaction is being assessed as one of a set of possible predictors for of the disease (Ponsen, Stoffers, Twisk, Wolters, & Berendse, 2009). Diagnosis of PD is difficult, even in specialty clinics (Jankovic, 2008). Early diagnosis could have a large impact on the quality of life of an individual because if they are diagnosed before the onset of motor symptoms, they will have more time to plan and consider different treatment options. Early detection could also aid physicians treating the patient as it would allow them more time to assess proper intervention methods that may slow, halt, or reverse the course of the disease. Olfactory deficits are also thought to predict later cognitive dysfunction in PD (Duda, Chahine, & Morley, 2016) and in Alzheimer disease, which is primarily marked by cognitive dysfunction, nearly all patients have severe olfactory deficits (Zou et al., 2016).
While olfactory dysfunction can be evaluated using different methods (Doty, 2015), one of the most widely used assessment tools is the University of Pennsylvania Smell Identification Test (UPSIT). The UPSIT has high test-retest reliability and well-established norms for age and sex (Doty et al., 1984). It is a forced-choice, scratch-and-sniff test that evaluates 40 microencapsulated odors. After a pencil scratch releases an odor, the subject is asked to identify the odor from four verbally stated options. Each correctly recognized odor results in one point, so subjects able to correctly identify all odors receive a score of 40. While the UPSIT is widely used to access olfactory deficit, it also contains a potential confound. Lower UPSIT scores could be attributed to cognitive impairment if the subject is unable to remember the odor presented, remember all the possible verbally administered answers, or cannot reliably process odor information. If cognitive deficits, not the inability to smell, are driving low UPSIT scores, subjects taking the test at different times might get similar scores, but misidentify different odors. Indeed, this was reported by Markopoulou et al. (2016) for both PD and age-matched control subjects with modest olfactory dysfunction.
Characterizing how potentially subtle cognitive impairments impact olfactory dysfunction has the potential to influence how olfactory tests are used to aid in diagnosis of neurodegenerative diseases. If subtle cognitive impairments impact measurement of olfactory dysfunction, then assessment for such cognitive impairments might be a more sensitive measure in predicting incipient motor symptoms of PD than olfactory-based measurements of olfactory dysfunction. If so, that could precede or replace assessment of olfactory dysfunction. We already know, however, that standard quick tests for cognitive impairment that are used clinically, such as the Montreal Cognitive Assessment (MoCA), (Hoops et al., 2009) cannot be used to explain the cognitive processes that may underlie the lack of odor-identification reproducibility seen in those with PD. The aim of this research is to evaluate whether subtle cognitive deficits impact olfactory function scores and thereby impact the assessment of olfactory dysfunction.