Nathan H. Kung

Neurologist-associated reduction in PD-related hospitalizations and health care expenditures

Objective: To investigate the impact of neurologist care on Parkinson disease (PD)–related hospitalizations. Recent data indicate that neurologist treatment in PD may be associated with improved survival, yet is underutilized. Factors contributing to this improved survival remain unknown, but may be due in part to optimal disease treatment or avoidance of disease-related complications. Methods: This was a retrospective cohort study of Medicare beneficiaries diagnosed with PD in 2002 and still living in 2006. Hospitalization for PD-related (neurodegenerative disease, psychosis, depression, urinary tract infection, and traumatic injury) and general medical (hypertension, diabetes, congestive heart failure, angina, and gastrointestinal obstruction) illnesses was compared by PD treating physician specialty using Cox proportional hazard models, adjusting for confounders. Secondary analyses included PD-related rehospitalization and cost stratified by frequency of neurologist care. Results: We identified 24,929 eligible incident PD cases; 13,489 had neurologist care. There were 9,112 PD-related hospitalizations, and these occurred and recurred less often among neurologist-treated patients. Neurologist PD care was associated with lower adjusted odds of both initial and repeat hospitalization for psychosis (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.59–0.86), urinary tract infection (HR 0.74, 0.63–0.87), and traumatic injury (HR 0.56, 0.40–0.78). PD-related outcomes improved with frequency of neurologist care in a stepwise manner. Odds of general illness hospitalization or hospitalization did not differ by neurologist involvement. Conclusions: Regular neurologist care in PD is specifically associated with lower risk of hospitalization and rehospitalization for several PD-related illnesses. This may reflect an improved ability of neurologists to prevent, recognize, or treat PD complications.

Disparities in deep brain stimulation surgery among insured elders with Parkinson disease

Objective: To identify sociodemographic, clinical, and physician/practice factors associated with deep brain stimulation (DBS). DBS is a proven surgical therapy for Parkinson disease (PD), but is recommended only for patients with excellent health, results in significant out-of-pocket costs, and requires substantial physician involvement. Methods: Retrospective cohort study of more than 657,000 Medicare beneficiaries with PD. Multivariable logistic regression models examined the association between demographic, clinical, socioeconomic status (SES), and physician/practice factors, and DBS therapy. Results: There were significant disparities in the use of DBS therapy among Medicare beneficiaries with PD. The greatest disparities were associated with race: black (adjusted odds ratio [AOR] 0.20, 95% confidence interval [CI] 0.16–0.25) and Asian (AOR 0.55, 95% CI 0.44–0.70) beneficiaries were considerably less likely to receive DBS than white beneficiaries. Women (AOR 0.79, 95% CI 0.75–0.83) also had lower odds of receiving DBS compared with men. Eighteen percent of procedures were performed on patients with PD who had cognitive impairment/dementia, a reported contraindication to DBS. Beneficiaries treated in minority-serving PD practices were less likely to receive DBS, regardless of individual race (AOR 0.76, 95% CI 0.66–0.87). Even after adjustment for demographic and clinical covariates, high neighborhood SES was associated with 1.4-fold higher odds of receiving DBS (AOR 1.42, 95% CI 1.33–1.53). Conclusions: Among elderly Medicare beneficiaries with PD, race, sex, and neighborhood SES are strong independent predictors of DBS receipt. Racial disparities are amplified when adjusting for physician/clinic characteristics. Future investigations of the demographic differences in clinical need/usefulness of DBS, ease of DBS attainment, and actual/opportunity DBS costs are needed to inform policies to reduce DBS disparities and improve PD quality of care.

Isolated Ocular Motor Nerve Palsies.

An isolated ocular motor nerve palsy is defined as dysfunction of a single ocular motor nerve (oculomotor, trochlear, or abducens) with no associated or localizing neurologic signs or symptoms. When occurring in patients aged 50 or older, the most common cause is microvascular ischemia, but serious etiologies such as aneurysm, malignancy, and giant cell arteritis should always be considered. In this article, the authors review the clinical approach, anatomy, and differential diagnosis of each isolated ocular motor nerve palsy and discuss the clinical characteristics, pathophysiology, and treatment of microvascular ischemia.

Epidemiology and neuropsychiatric manifestations of Young Onset Parkinson's Disease in the United States.

BACKGROUND To determine the demographic distribution of Young Onset Parkinsons Disease (YOPD) in the United States and to quantify the burden of neuropsychiatric disease manifestations. METHODS Cross sectional study of 3,459,986 disabled Americans, aged 30-54, who were receiving Medicare benefits in the year 2005. We calculated race and sex distributions of YOPD and used logistic regression to compare the likelihood of common and uncommon psychiatric disorders between beneficiaries with YOPD and the general disability beneficiary population, adjusting for race, age, and sex. RESULTS We identified 14,354 Medicare beneficiaries with YOPD (prevalence = 414.9 per 100,000 disabled Americans). White men comprised the majority of cases (48.9%), followed by White women (34.7%), Black men (6.8%), Black women (5.0%), Hispanic men (2.4%), and Hispanic women (1.2%). Asian men (0.6%) and Asian women (0.4%) were the least common race-sex pairs with a YOPD diagnosis in this population (chi square, p < 0.001). Compared to the general population of medically disabled Americans, those with YOPD were more likely to receive medical care for depression (OR: 1.89, 1.83-1.95), dementia (OR: 7.73, 7.38-8.09), substance abuse/dependence (OR: 3.00, 2.99-3.01), and were more likely to be hospitalized for psychosis (OR: 3.36, 3.19-3.53), personality/impulse control disorders (OR: 4.56, 3.28-6.34), and psychosocial dysfunction (OR: 3.85, 2.89-5.14). CONCLUSIONS Young Onset Parkinsons Disease is most common among white males in our study population. Psychiatric illness, addiction, and cognitive impairment are more common in YOPD than in the general population of disabled Medicare beneficiaries. These may be key disabling factors in YOPD.

Incidence and Causes of Overdiagnosis of Optic Neuritis

Importance Diagnostic error is an important source of medical error. Overdiagnosis of optic neuritis may prompt unnecessary and costly diagnostic tests, procedures, and treatments. Objective To assess the incidence of and characterize factors contributing to overdiagnosis of acute optic neuritis. Design, Setting, and Participants In this retrospective clinic-based cross-sectional study of new patient encounters, 122 patients referred for acute optic neuritis at a university-based Midwestern neuro-ophthalmology clinic between January 2014 and October 2016 were studied. Data were analyzed from September 2016 to July 2017. Interventions Definite diagnosis was determined by neuro-ophthalmologists. For patients with alterative diagnoses, the Diagnosis Error Evaluation and Research taxonomy tool was applied to categorize the type of diagnostic error. Main Outcomes and Measures The primary outcome was the primary type of diagnostic error in patients erroneously diagnosed as having optic neuritis. Secondary outcomes included final diagnosis and interventions undergone prior to referral. Results A total of 122 patients were referred with acute optic neuritis during the study period; 88 (72.1%) were female, and the mean (SD) age was 42.6 (14.0) years. Of these, 49 patients (40.2%; 95% CI, 31.4-49.4) were confirmed to have optic neuritis, and 73 (59.8%; 95% CI, 50.6-68.6) had an alternative diagnosis. The most common alternative diagnoses were headache and eye pain, functional visual loss, and other optic neuropathies, particularly nonarteritic anterior ischemic optic neuropathy. The most common diagnostic error was eliciting or interpreting critical elements of history, which occurred in 24 of 73 patients (33%) with alternative diagnoses. Other common errors included errors weighing or considering alternative diagnoses (23 patients [32%]), errors weighing or interpreting physical examination findings (15 patients [21%]), and misinterpreting diagnostic test results (11 patients [15%]). In patients with alterative diagnoses, 12 (16%) had normal magnetic resonance imaging findings preceding the referral, 12 (16%) had received a lumbar puncture, and 8 (11%) had received unnecessary treatment with intravenous steroids. Conclusions and Relevance These data suggest that nearly 60% (95% CI, 50.6-68.6) of patients referred for optic neuritis have an alternative diagnosis, with the most common errors being overreliance on a single item of history and failure to consider alternative diagnoses. Understanding pitfalls leading to overdiagnosis of optic neuritis may improve clinicians’ diagnostic process.

Vertebrobasilar Dolichoectasia Causing An Optic Tract Syndrome

Vertebrobasilar dolichoectasia (VBD) is characterized by significant dilation, elongation, and tortuosity of the vertebrobasilar system. We present a unique case of VBD, confirmed by neuroimaging studies, showing vascular compression of the right optic tract and lower cranial nerves leading to an incongruous left homonymous inferior quadrantanopia and glossopharyngeal neuralgia.

Ocular Neuromyotonia Associated with Chronic Inflammatory Demyelinating Polyneuropathy

Abstract Ocular neuromyotonia (ONM) is a neuro-ophthalmic disorder characterized by episodic diplopia caused by contraction of one or more ocular muscles due to spontaneous excitation of the respective ocular motor nerve. We report a patient whose ocular neuromyotonia arose in the setting of a subacute demyelinating polyneuropathy consistent with chronic inflammatory demyelinating polyneuropathy (CIDP) and subsequently resolved following the initiation of intravenous immunoglobulin (IVIg) for her neuropathy. Our patient provides additional evidence towards the role of demyelination and ephaptic neurotransmission in ocular neuromyotonia and also represents the first reported case of ocular neuromyotonia associated with a systemic neurological condition.

Association of Preclinical Alzheimer Disease With Optical Coherence Tomographic Angiography Findings

Importance Biomarker testing for asymptomatic, preclinical Alzheimer disease (AD) is invasive and expensive. Optical coherence tomographic angiography (OCTA) is a noninvasive technique that allows analysis of retinal and microvascular anatomy, which is altered in early-stage AD. Objective To determine whether OCTA can detect early retinal alterations in cognitively normal study participants with preclinical AD diagnosed by criterion standard biomarker testing. Design, Setting, and Participants This case-control study included 32 participants recruited from the Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University in St Louis, St Louis, Missouri. Results of extensive neuropsychometric testing determined that all participants were cognitively normal. Participants underwent positron emission tomography and/or cerebral spinal fluid testing to determine biomarker status. Individuals with prior ophthalmic disease, media opacity, diabetes, or uncontrolled hypertension were excluded. Data were collected from July 1, 2016, through September 30, 2017, and analyzed from July 30, 2016, through December 31, 2017. Main Outcomes and Measures Automated measurements of retinal nerve fiber layer thickness, ganglion cell layer thickness, inner and outer foveal thickness, vascular density, macular volume, and foveal avascular zone were collected using an OCTA system from both eyes of all participants. Separate model III analyses of covariance were used to analyze individual data outcome. Results Fifty-eight eyes from 30 participants (53% female; mean [SD] age, 74.5 [5.6] years; age range, 62-92 years) were included in the analysis. One participant was African American and 29 were white. Fourteen participants had biomarkers positive for AD and thus a diagnosis of preclinical AD (mean [SD] age, 73.5 [4.7] years); 16 without biomarkers served as a control group (mean [SD] age, 75.4 [6.6] years). The foveal avascular zone was increased in the biomarker-positive group compared with controls (mean [SD], 0.364 [0.095] vs 0.275 [0.060] mm2; P = .002). Mean (SD) inner foveal thickness was decreased in the biomarker-positive group (66.0 [9.9] vs 75.4 [10.6] &mgr;m; P = .03). Conclusions and Relevance This study suggests that cognitively healthy individuals with preclinical AD have retinal microvascular abnormalities in addition to architectural alterations and that these changes occur at earlier stages of AD than has previously been demonstrated. Longitudinal studies in larger cohorts are needed to determine whether this finding has value in identifying preclinical AD.

Skew Deviation and Partial Ocular Tilt Reaction Due to Intratympanic Gentamicin Injection, with Review of the Literature

ABSTRACT Skew deviation is a rare side effect of intratympanic gentamicin injection for intractable Meniere’s disease. When the skew deviation is accompanied by pathologic head tilt and ocular torsion, the result is an ocular tilt reaction (OTR). The authors report the case of a 56-year-old man with refractory Meniere’s disease who developed binocular vertical diplopia following intratympanic gentamicin injection and was found to have skew deviation and a partial ocular tilt reaction. The authors also review the reported cases of skew deviation following intratympanic gentamicin and confirm this phenomenon, which has only rarely been reported in the literature.

A Middle-aged Man With Progressive Ophthalmoparesis, Ataxia, and Spastic Paraparesis

A 50-year old man presented for evaluation of progressive gait ataxia with a superimposed spastic paraparesis. During his clinic visit, he was also observed to have slow and limited eye movements. In this article, we discuss the clinical approach to this triad of symptoms and guide the reader to discover the patient’s ultimate genetic diagnosis.