- •Working memory may separate true SWEDDs from PD patients and healthy controls.
- •True SWEDDS show similar baseline cognition to non-true SWEDDs.
- •True SWEDDs, PD patients and controls show decline in working memory with time.
- •In contrast, non-true SWEDDs show stable cognitive symptoms with time.
The cognitive profile of patients with longstanding clinical Parkinsonism possessing scans without evidence of dopaminergic deficit (SWEDD) remains unclear from previous studies.
We studied 47 patients recruited in the Parkinson's Progression Markers Initiative with SWEDD as baseline diagnosis. They were subdivided by final clinical diagnoses after a 2-year follow-up period into 25 patients with either clinical evidence of Parkinson's Disease (PD) or unclassified parkinsonism and normal SPECT imaging (“true SWEDDs”), 6 patients with a psychogenic illness exhibiting Parkinsonism, 6 patients who had phenoconverted to PD based on reduced striatal dopaminergic activity on imaging, and 10 patients with another tremulous condition. Cognitive symptoms were compared between these subgroups, as well as with 62 PD patients and 195 healthy controls (HCs), at baseline and follow-ups.
A significant difference in working memory was found between true SWEDDs and HCs (P = 0.009), but not true SWEDDs and PD patients (P = 0.432), nor PD patients and HCs (P = 0.154). The prevalence of attentional impairment was also significantly different between the three groups (P < 0.001). SWEDD subgroups possessed similar cognitive symptoms irrespective of their final clinical diagnosis. Psychogenic, phenoconverted and tremulous SWEDDs also possessed stable cognitive symptoms over the 2-year period whilst true SWEDDs, PD patients and HCs experienced significant changes in working memory.
Our results, particularly relating to working memory and attention, add to the knowledge of other true SWEDD non-motor symptoms to facilitate earlier diagnosis and improved management strategies for these patients.
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- Longitudinal follow-up of SWEDD subjects in the PRECEPT study.Neurology. May 2014; 82: 1791-1797https://doi.org/10.1212/WNL.0000000000000424
- Cognition in patients with a clinical diagnosis of Parkinson disease and scans without evidence of dopaminergic deficit (SWEDD): 2-year follow-up.Cogn. Behav. Neurol. Off. J. Soc. Behav. Cogn. Neurol. 2016; 29: 190-196https://doi.org/10.1097/WNN.0000000000000107
- Diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT: a clinical follow up study.Front. Aging Neurosci. Apr. 2014; 6: 56https://doi.org/10.3389/fnagi.2014.00056
- Neuropsychological test performance in parkinsonism without dopaminergic deficiency on [123I]-FP-CIT SPECT imaging.J. Int. Neuropsychol. Soc. JINS. Jul. 2018; 24: 646-651https://doi.org/10.1017/S1355617718000164
- Diagnostic criteria for mild cognitive impairment in Parkinson’s disease: Movement Disorder Society task force guidelines.Mov. Disord. 2012; 27: 349-356https://doi.org/10.1002/mds.24893
- Neuropsychological spectrum in early PD: insights from controlled and automatic behavioural regulation.Neurosci. Biobehav. Rev. Jul. 2021; 126: 465-480https://doi.org/10.1016/j.neubiorev.2021.04.003
- Progression of nonmotor symptoms in subgroups of patients with non-dopamine-deficient parkinsonism.Mov. Disord. Off. J. Mov. Disord. Soc. Mar. 2016; 31: 344-351https://doi.org/10.1002/mds.26456
- Clinical Epidemiology: The Essentials, Fifth.Lippincott Williams and Wilkins, Philadelphia, PA2012
- Patterns of motor and non-motor features in medication-naïve parkinsonism.Neuroepidemiology. 2015; 45: 59-69https://doi.org/10.1159/000437228
- Neuropsychological test performance in parkinsonism without dopaminergic deficiency on [123I]-FP-CIT SPECT imaging.J. Int. Neuropsychol. Soc. JINS. 2018; 24: 646-651https://doi.org/10.1017/S1355617718000164
- Sniffing out cognitive decline in patients with and without evidence of dopaminergic deficit.Clin. Park. Relat. Disord. Jan. 2019; 1: 77-81https://doi.org/10.1016/j.prdoa.2019.09.002
- Cognitive dysfunction in rapid eye movement sleep behavior disorder.Sleep Biol. Rhythms. 2013; 11: 21-26https://doi.org/10.1111/j.1479-8425.2012.00547.x
- Sleep disorders and cognitive dysfunctions in Parkinson’s disease: a Meta-analytic study.Neuropsychol. Rev. Dec. 2021; 31: 643-682https://doi.org/10.1007/s11065-020-09473-1
- Anxiety is associated with cognitive impairment in newly-diagnosed Parkinson’s disease.Parkinsonism Relat. Disord. Mar. 2017; 36: 63-68https://doi.org/10.1016/j.parkreldis.2017.01.001
- Cognitive impairment and depression—cause, consequence, or coincidence?.JAMA Psychiatry. Mar. 2019; 76: 239-240https://doi.org/10.1001/jamapsychiatry.2018.3631
- Cognitive and neuroanatomical correlates of neuropsychiatric symptoms in Parkinson’s disease: a systematic review.J. Neurol. Sci. Sep. 2015; 356: 32-44https://doi.org/10.1016/j.jns.2015.06.037
- Montreal cognitive assessment in a 63- to 65-year-old Norwegian cohort from the general population: data from the Akershus cardiac examination 1950 study.Dement. Geriatr. Cogn. Disord. Extra. 2017; 7: 318-327https://doi.org/10.1159/000480496
Published online: July 25, 2022
Accepted: July 20, 2022
Received in revised form: June 9, 2022
Received: March 13, 2022
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