Gupta, Harsh

AbstractIntroduction/AimsComplex repetitive discharges (CRDs) are spontaneous electromyography (EMG) waveforms often associated with chronic neurogenic or myopathic diseases, but incidentally identified CRDs have also been described. In this study we describe the distribution and possible significance of incidentally seen CRDs in otherwise normal electrodiagnostic studies.MethodsA retrospective chart review was performed of all patients with CRDs incidentally documented on otherwise normal electrodiagnostic studies at Mayo Clinic from January 2013 through December 2020. Each patient's clinical symptoms, referral reason, electrodiagnostic report, and imaging studies were analyzed using descriptive statistics.ResultsNinety‐four patients (86 females; mean age, 62 years; range, 20 to 86 years) and 107 CRDs were studied. The most common neuromuscular reasons for electrodiagnostic referrals included radiculopathy, peripheral neuropathy, and myopathy. Mean symptom duration was 43 months (range, 1 to 312 months). Eighty‐five patients had a CRD identified in one muscle (range, in all patients, one to five muscles). CRDs were identified most frequently in tensor fasciae latae (n = 21), biceps brachii (n = 16), and gluteus maximus (n = 9). Of the 58 patients in whom imaging was available, 46 (79%) had abnormalities that corresponded to the myotome in which the CRDs were visualized, most commonly L5 (n = 19) and C6 (n = 12). Of these 46 patients, 28 (61%) were referred for radicular or limb pain.DiscussionCRDs can be incidentally noted on otherwise normal electrodiagnostic studies, most commonly in L5 and C6 myotomes. The mechanism of CRDs in the absence of electrodiagnostic features of axon loss or remodeling is unknown.

Background: Imaging biomarkers have the potential to distinguish between different brain pathologies based on the type of ligand used with PET. AV-45 PET (florbetapir, Amyvid™) is selective for the neuritic plaque amyloid of Alzheimer’s disease (AD), while AV-133 PET (florbenazine) is selective for VMAT2, which is a dopaminergic marker. Objective: To report the clinical, AV-133 PET, AV-45 PET, and neuropathological findings of three clinically diagnosed dementia patients who were part of the Avid Radiopharmaceuticals AV133-B03 study as well as the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND). Methods: Three subjects who had PET imaging with both AV-133 and AV-45 as well as a standardized neuropathological assessment were included. The final clinical, PET scan, and neuropathological diagnoses were compared. Results: The clinical and neuropathological diagnoses were made blinded to PET scan results. The first subject had a clinical diagnosis of dementia with Lewy bodies (DLB); AV-133 PET showed bilateral striatal dopaminergic degeneration, and AV-45 PET was positive for amyloid. The final clinicopathological diagnosis was DLB and AD. The second subject was diagnosed clinically with probable AD; AV-45 PET was positive for amyloid, while striatal AV-133 PET was normal. The final clinicopathological diagnosis was DLB and AD. The third subject had a clinical diagnosis of DLB. Her AV-45 PET was positive for amyloid and striatal AV-133 showed dopaminergic degeneration. The final clinicopathological diagnosis was multiple system atrophy and AD. Conclusion: PET imaging using AV-133 for the assessment of striatal VMAT2 density may help distinguish between AD and DLB. However, some cases of DLB with less-pronounced nigrostriatal dopaminergic neuronal loss may be missed.

ABSTRACTBackgroundAbnormal color vision and contrast acuity may have significant impact on daily activities.ObjectiveEvaluate color visual acuity, at high and low contrast, in Parkinson's disease (PD) and controls using an iPad application.MethodsColor visual acuity was tested with the Variable Contrast Acuity Chart (King‐Devick Test LLC, Oakbrook Terrace, IL) on an iPad 2 at 40 cms using five colors (red, green, blue, yellow, and black) at low (2.5%) and high (100%) contrast. A numerical score (0–95) was assigned based on the number of correctly identified letters.ResultsThirty‐six PD (mean ± standard deviation age 68 ± 10 years) and 36 controls (72 ± 11.2 years) were studied. PD disease duration was 6.4 ± 4.6 years; MDS‐UPDRS part II was 11.7 ± 7.0, and part III was 24.5 ± 9.9. After adjusting for age and sex, PD patients had significantly (P < 0.05) lower scores at high (100%) as well as low (2.5%) contrast for all five colors tested (red, green, blue, yellow, and black), except yellow low contrast (2.5%; P = 0.10). The largest effect size (0.88) was with yellow high contrast, and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy using a cut‐off score of 82 was 31%, 97%, 92%, 58%, and 64%, respectively. No correlation to disease duration was found.ConclusionsThis iPad application may be a simple‐to‐use biomarker for assessing color vision in PD. Further research is needed to determine disease specificity and whether there is a role in monitoring disease progression, treatment response, and identifying prodromal PD.

AbstractBackgroundClinical diagnostic criteria for PD rely on rest tremor, bradykinesia, and rigidity. These features are non‐specific and neuropathological confirmation remains the gold standard for diagnosis. This study presents data on clinical certainty ratings in autopsy‐proven PD.MethodsSubjects were assessed annually by a movement disorders specialist and assigned to a clinical certainty group for PD based on multiple clinical features before autopsy. The three groups considered for analysis are as follows: Group I 0–49% certainty, Group II 50‐89% certainty, and Group III 90–100% certainty. All subjects were autopsied and had a standardized neuropathological assessment.Results275 subjects were assigned a PD certainty at their last visit before death. Group I had 80 subjects, Group II 56 subjects, and Group III 139 subjects. The clinical features recorded in Group I, II, and III, were as follows: rest tremor, bradykinesia, rigidity, postural instability, asymmetric onset, persistent asymmetry, current response to dopaminergic treatment, motor fluctuations, and dyskinesia. Rigidity, postural instability, asymmetric onset, current response to dopaminergic treatment, motor fluctuation, and dyskinesia were more likely to be present in the group which was rated with higher certainty. The final diagnosis of PD was confirmed by neuropathological assessment in 85% of the patients in Group III as compared to 30% in Group II and 5% in Group I.ConclusionsHigh certainty (90–100%) had strong positive predictive value (85%) for autopsy‐proven PD as compared to either lower certainty groups (0–49% and 50–89%) which had lower predictive value (5% and 30% respectively).