Advances in the neuroimaging of motor disorders.

Neuroimaging is a valuable adjunct to the history and examination in the evaluation of motor system disorders. Conventional imaging with computed tomography or magnetic resonance imaging depicts important anatomic information and helps to identify imaging patterns which may support diagnosis of a specific motor disorder. Advanced imaging techniques can provide further detail regarding volume, functional, or metabolic changes occurring in nervous system pathology. This chapter is an overview of the advances in neuroimaging with particular emphasis on both standard and less well-known advanced imaging techniques and findings, such as diffusion tensor imaging or volumetric studies, and their application to specific motor disorders. In addition, it provides reference to emerging imaging biomarkers in motor system disorders such as Parkinson disease, amyotrophic lateral sclerosis, and Huntington disease, and briefly reviews the neuroimaging findings in different causes of myelopathy and peripheral nerve disorders.

Recurrent tumefactive demyelinating lesions in an elderly woman.

Here we describe a 72-year old Caucasian woman who presented with progressive left hemiparesis and hemisensory deficits due to a pathology-confirmed tumefactive demyelinating lesion in the right frontoparietal region. Symptoms improved with glucocorticoids and plasmapheresis, but five months following initial presentation, the patient developed right visual field deficits and acute encephalopathy. Brain imaging revealed near resolution of the initial lesion with interval development of new multifocal tumefactive demyelinating lesions. This case highlights several atypical features associated with tumefactive demyelinating disease, including an older age of onset and recurrent, treatment-resistant lesions. Clinical and neuroimaging features which may be helpful in diagnosing this rare disorder are reviewed.

Acute Ischemic Stroke Presentation Masked by Falsely Localizing Motor Seizure: A Clinical Case Series.

In this case series, we describe a novel observation in which 4 patients with acute ischemic stroke secondary to large vessel occlusion and no history of seizure present with focal seizure activity localizable to a chronic, contralateral infarct. The explanation for this phenomenon is unknown but may be due to a combination of effects involving disrupted interhemispheric inhibitory connections and epileptogenic changes involving chronically infarcted tissue.

Artificial Intelligence-Enabled Electrocardiogram for Atrial Fibrillation Identifies Cognitive Decline Risk and Cerebral Infarcts.

OBJECTIVE: To investigate whether artificial intelligence-enabled electrocardiogram (AI-ECG) assessment of atrial fibrillation (AF) risk predicts cognitive decline and cerebral infarcts. PATIENTS AND METHODS: This population-based study included sinus-rhythm ECG participants seen from November 29, 2004 through July 13, 2020, and a subset with brain magnetic resonance imaging (MRI) (October 10, 2011, through November 2, 2017). The AI-ECG score of AF risk calculated for participants was 0-1. To determine the AI-ECG-AF relationship with baseline cognitive dysfunction, we compared linear mixed-effects models with global and domain-specific cognitive z-scores from longitudinal neuropsychological assessments. The AI-ECG-AF score was logit transformed and modeled with cubic splines. For the brain-MRI subset, logistic regression evaluated correlation of the AI-ECG-AF score and the high-threshold, dichotomized AI-ECG-AF score with infarcts. RESULTS: Participants (N=3729; median age, 74.1 years) underwent cognitive analysis. Adjusting for age, sex, education, and APOE ɛ4-carrier status, the AI-ECG-AF score correlated with lower baseline and faster decline in global-cognitive z-scores (P=.009 and P=.01, respectively, non-linear-based spline-models tests) and attention z-scores (P<.001 and P=.01, respectively). Sinus-rhythm-ECG participants (n=1373) underwent MRI. As a continuous measure, the AI-ECG-AF score correlated with infarcts but not after age and sex adjustment (P=.52). For dichotomized analysis, an AI-ECG-AF score greater than 0.5 correlated with infarcts (OR, 4.61; 95% CI, 2.45-8.55; P<.001); even after age and sex adjustment (OR, 2.09; 95% CI, 1.06-4.07; P=.03). CONCLUSION: The AI-ECG-AF score correlated with worse baseline cognition and gradual global cognition and attention decline. High AF probability by AI-ECG-AF score correlated with MRI cerebral infarcts. However, most infarcts observed in our cohort were subcortical, suggesting that AI-ECG not only predicts AF but also detects other non-AF cardiac disease markers and correlates with small vessel cerebrovascular disease and cognitive decline.

Neurological manifestations of thrombotic microangiopathy syndromes in adult patients.

The objective of this study was to compare the frequency and severity of neurologic manifestations in adult patients diagnosed with thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS) and atypical HUS (aHUS). This is a retrospective cohort study of adult patients diagnosed with TTP, HUS and atypical HUS hospitalized at a tertiary center between January 2004 and October 2016. A total of 42 TTP, 16 HUS and 20 aHUS episodes were reviewed to collect clinical, laboratory and radiographic data, as well as information regarding long-term functional outcome. Neurologic symptoms are more common in patients with TTP and HUS as compared to aHUS (p < 0.001 and p = 0.002, respectively). Encephalopathy occurred in 29 TTP (69%) and 11 HUS (68%) episodes. Focal deficits were only observed in patients with TTP (n = 8 [19%]). Seizures were most commonly seen in HUS patients (n = 8 [50%]). Posterior reversible encephalopathy syndrome (PRES) was the most common neuroimaging finding in these syndromes; ischemic infarcts and hemorrhages occurred uncommonly. There was no correlation between presence of neurologic symptoms or neuroimaging abnormalities and poor outcome. Patients with TTP and HUS appear to have a similar spectrum of neurologic manifestations, whereas neurologic involvement is less common in aHUS. PRES is the most common imaging abnormality, and may present atypically. Despite presence of neurologic symptoms or neuroimaging abnormalities, patients with thrombotic microangiopathy (TMA) tend to have favorable long-term outcomes.

Cerebral venous sinus thrombosis associated with spontaneous heparin-induced thrombocytopenia syndrome after total knee arthroplasty.

Spontaneous heparin-induced thrombocytopenia (HIT) syndrome, characterized by clinical and serologic features of HIT despite the absence of proximate heparin exposure, can be triggered by total knee arthroplasty (TKA). A 56-year-old female receiving aspirin thromboprophylaxis post-TKA presented with aphasia and thrombocytopenia on post-operative day 11. Imaging studies revealed cerebral venous sinus thrombosis (CVST) and intravenous bivalirudin was initiated. Her serum tested strong-positive for IgG anti-PF4/polyanion complexes and serotonin-release assay in the presence and absence of heparin; strong-positive IgG-specific chemiluminescent immunoassay; and moderate-positive latex immunoturbidimetric assay. Two 65 g doses of IVIG were administered. With the improvement of her platelet count, she was transitioned from bivalirudin to warfarin. At one-year follow-up, she remained free of recurrent thrombosis and neurologically stable with a normal platelet count. Previous reports of post-TKA spontaneous HIT syndrome include venous/arterial thrombosis and adrenal hemorrhage, and this report of CVST expands the clinical spectrum of this rare complication of orthopedic surgery.