Utility of tremor electrophysiology studies.

Objective: To determine the utility of tremor electrophysiology testing in differentiating clinically indeterminate tremor due to organic, functional, and mixed tremor types.

Background: Prior studies have shown that electrophysiological studies increase diagnostic sensitivity of tremor syndromes; however, few have examined mixed organic and functional tremors.

Methods: Patients referred for tremor to the Mayo Clinic, Rochester movement disorders lab were consecutively selected and retrospectively reviewed.

PSP-like syndrome after aortic surgery in adults (Mokri syndrome).

Background: A rare progressive supranuclear palsy-like syndrome seemingly triggered by aortic surgery was first described in 2004. This largest case series to date describes the features of this syndrome.

Methods: We searched the Mayo Clinic electronic medical records using the advanced cohort explorer search engine for patients evaluated for neurologic symptoms after cardiac-aortic surgery in the past 30 years.

Conjugal multiple system atrophy: Chance, shared risk factors, or evidence of transmissibility?

Objective: To describe conjugal multiple system atrophy (MSA) in a couple married for 44 years, and to report environmental risk factors possibly contributing to the occurrence.

Methods: Case description of conjugal MSA with report of shared environmental risk factors and retrospective review of consecutively diagnosed MSA patients between 1998 and 2012 with autonomic reflex screen at Mayo Clinic, Rochester (clinical series). Probability calculation was based on the age-specific point prevalence of MSA.

Camptocormia: Etiology, diagnosis, and treatment response.

Background: We sought to determine the etiologies, diagnostic testing, and management of a retrospective cohort of patients with camptocormia evaluated at a single center.

Methods: We reviewed medical records of all adult patients evaluated at Mayo Clinic Rochester with a diagnosis of camptocormia from 2000 to 2014. Demographic and clinical data were abstracted and analyzed.

Glycine receptor modulating antibody predicting treatable stiff-person spectrum disorders.

Background: Glycine receptor alpha-1 subunit (GlyRα1)-immunoglobulin G (IgG) is diagnostic of stiff-person syndrome (SPS) spectrum but has been reported detectable in other neurologic diseases for which significance is less certain.

Methods: To assess GlyRα1-IgGs as biomarkers of SPS spectrum among patients and controls, specimens were tested using cell-based assays (binding [4°C] and modulating [antigen endocytosing, 37°C]). Medical records of seropositive patients were reviewed.

Orthostatic myoclonus after brain tumor radiation: Insights from two lesional cases.

Introduction: Orthostatic myoclonus (OM) is a recognized syndrome of gait unsteadiness accompanied by lower limb myoclonus provoked by the assumption of an upright posture. OM typically affects the elderly and is often associated with neurodegenerative disease. We sought to review the clinical and electrophysiologic characteristics of OM due to brain tumor treatment, the first reported lesional cases of this rare disorder.

Precise stimulation location optimizes speech outcomes in essential tremor.

Background: Deep brain stimulation for essential arm tremor is often complicated by dysarthria and persistent voice tremor.

Objective: To determine the relationship of stimulation location to speech outcomes following bilateral thalamic deep brain stimulation (DBS) for essential tremor (ET).

Methods: Eighteen patients undergoing bilateral DBS for ET were prospectively studied.

Stimulation-Induced Transient Nonmotor Psychiatric Symptoms following Subthalamic Deep Brain Stimulation in Patients with Parkinson's Disease: Association with Clinical Outcomes and Neuroanatomical Correlates.

Background: The clinical and neurobiological underpinnings of transient nonmotor (TNM) psychiatric symptoms during the optimization of stimulation parameters in the course of subthalamic nucleus deep brain stimulation (STN-DBS) remain under intense investigation.

Methods: Forty-nine patients with refractory Parkinson's disease underwent bilateral STN-DBS implants and were enrolled in a 24-week prospective, naturalistic follow-up study. Patients who exhibited TNM psychiatric manifestations during DBS parameter optimization were evaluated for potential associations with clinical outcome measures.

Repetitive exercise dystonia: A difficult to treat hazard of runner and non-runner athletes.

Introduction: Runner's dystonia has previously been described in small series or case reports as a lower limb, task-specific dystonia. We have occasionally encountered this disorder and recognized the same phenomenon in non-runners regularly engaging in lower limb exercise. We wished to characterize the syndrome further, including outcomes, treatment, and the diagnostic usefulness of electrophysiology.

Orthostatic tremor: Clinical, electrophysiologic, and treatment findings in 184 patients.

Objective: To evaluate the clinical, electrophysiologic, and treatment outcome features of orthostatic tremor (OT) in a large case series.

Methods: We performed medical record review of 184 patients who met clinical and electrodiagnostic criteria for OT from 1976 to 2013 at the Mayo Clinic. Demographic, clinical, electrophysiologic, and treatment data were extracted.

Clinical features and autonomic testing predict survival in multiple system atrophy.

Multiple system atrophy is characterized by autonomic failure along with motor symptoms of parkinsonism and/or cerebellar ataxia. There are differing reports on the influence of certain clinical features, including motor subtype (multiple system atrophy-parkinsonism versus multiple system atrophy-cerebellar ataxia), age of onset, gender, and early autonomic symptoms, on the survival in patients with multiple system atrophy. We sought to evaluate overall survival and predictors of survival in a large cohort of patients with multiple system atrophy seen at a single referral centre where objective autonomic testing is routinely performed for this indication.

Gamma oscillations precede interictal epileptiform spikes in the seizure onset zone.

Objective: To investigate the generation, spectral characteristics, and potential clinical significance of brain activity preceding interictal epileptiform spike discharges (IEDs) recorded with intracranial EEG.

Methods: Seventeen adult patients with drug-resistant temporal lobe epilepsy were implanted with intracranial electrodes as part of their evaluation for epilepsy surgery. IEDs detected on clinical macro- and research microelectrodes were analyzed using time-frequency spectral analysis.

DPPX potassium channel antibody: frequency, clinical accompaniments, and outcomes in 20 patients.

Objective: To describe the detection frequency and clinical associations of immunoglobulin G (IgG) targeting dipeptidyl-peptidase-like protein-6 (DPPX), a regulatory subunit of neuronal Kv4.2 potassium channels.

Methods: Specimens from 20 patients evaluated on a service basis by tissue-based immunofluorescence yielded a synaptic immunostaining pattern consistent with DPPX-IgG (serum, 20; CSF, all 7 available).

High frequency oscillations are associated with cognitive processing in human recognition memory.

High frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30-100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans demonstrate that physiological oscillations extend beyond the gamma frequency range, but their function in human cognitive processing has not been fully elucidated.

Lack of differential motor outcome with subthalamic nucleus region stimulation in Parkinson's disease.

Deep brain stimulation (DBS) has emerged as a viable therapy for Parkinson's disease (PD). The impact of subthalamic nucleus (STN) lead placement (lateral versus medial) on motor outcome, however, has not been systematically evaluated. Forty-eight patients with PD underwent STN-DBS surgery and were evaluated postoperatively for 48 weeks for motor improvement as measured by the Unified Parkinson's Disease Rating Scale (UPDRS) part III (standardized motor examination) and levodopa equivalent daily dose (LEDD).

Network oscillations modulate interictal epileptiform spike rate during human memory.

Eleven patients being evaluated with intracranial electroencephalography for medically resistant temporal lobe epilepsy participated in a visual recognition memory task. Interictal epileptiform spikes were manually marked and their rate of occurrence compared between baseline and three 2 s periods spanning a 6 s viewing period. During successful, but not unsuccessful, encoding of the images there was a significant reduction in interictal epileptiform spike rate in the amygdala, hippocampus, and temporal cortex.

Autoimmune chorea in adults.

Objectives: To determine the characteristics of adult-onset autoimmune chorea, and compare paraneoplastic and idiopathic subgroups.

Methods: Thirty-six adults with autoimmune chorea were identified at Mayo Clinic (Rochester, MN) from 1997 to 2012. Medical record and laboratory data were recorded.

Glycine receptor autoimmune spectrum with stiff-man syndrome phenotype.

Objectives: To determine whether glycine receptor α1 subunit-specific autoantibodies (GlyRα1-IgG) occur in a broader spectrum of brainstem and spinal hyperexcitability disorders than the progressive encephalomyelitis with rigidity and myoclonus phenotype recognized to date, and to ascertain disease specificity.

Design: Retrospective, case-control study.

Settings: Mayo Clinic, Rochester, Minnesota, and University of Barcelona, Spain.

Adult-onset opsoclonus-myoclonus syndrome.

BACKGROUND Little is known about adult-onset opsoclonus-myoclonus syndrome (OMS) outside of individual case reports. OBJECTIVE To describe adult-onset OMS. DESIGN Review of medical records (January 1, 1990, through December 31, 2011), prospective telephone surveillance, and literature review (January 1, 1967, through December 31, 2011).