Biomarkers in Neural Disorders
Condition: Parkinson's Disease; Alzheimer's Disease; Progressive Supranuclear Palsy; Essential Tremor; Multiple System Atrophy; Drug Induced Parkinson's Disease; Diffuse Lewy Body Disease; Myasthenia Gravis; Spinal Cord Injuries
MeSH terms: Myasthenia Gravis; Parkinson Disease; Alzheimer Disease; Spinal Cord Injuries; Essential Tremor; Multiple System Atrophy; Shy-Drager Syndrome; Supranuclear Palsy, Progressive; Lewy Body Disease
Study type: Observational

Summary: 
      This study seeks to establish the sensitivity and specificity of what appears to be a unique
      brainstem biomarker of Parkinson's Disease (PD) - an electrically induced olygosynaptic
      nasotrigeminal reflex response - in differentiating early stage PD from normal controls and
      from patients with various other neurodegenerative diseases. This study will additionally
      compare the biomarker to olfactory testing.
    

Detailed description: 
      Parkinson's disease (PD), a devastating age-related disease that is clinically defined by its
      effects on the motor system, afflicts more than six million people worldwide, imposing
      enormous burdens on patients, relatives, caretakers, and society in general. Diagnostic
      errors are common, particularly as symptoms first arise. The most common misdiagnoses are
      Alzheimer's disease (AD), essential tremor, and vascular pseudo-Parkinson's Disease. An
      accurate diagnosis is typically made at a later stage of the disease when marked and
      irreversible damage has occurred within the motor control system of the brain. Sensitive and
      specific biomarkers of the early stages of PD are urgently needed. Identification of such
      markers is critical for the development and assessment of medications and other interventions
      designed to eliminate or reduce the gradual and irreversible decline of neurons involved in
      the disorder. This study seeks to establish the sensitivity and specificity of what appears
      to be a unique brainstem biomarker of PD - an electrically induced trigeminal nerve blink
      reflex response - in differentiation of early stage PD from normal controls and such
      neurodegenerative diseases as early stage AD, progressive supranuclear palsy (PSP), and
      diffuse Lewy Body disease (DLBD). This study will additionally compare the biomarker to
      olfactory test results.
    

Intervention name(s): Electrical Brainstem Responses; Olfactory Tests; Visual Deprivation; Peripheral Nerve Stimulation
Intervention type(s): Other; Other; Other; Other
Intervention description(s): Eye blink responses will be induced using standard stimulating electrodes employed in surface electromyography (EMG). The subjects will recline with their eyes gently closed. Sticky electrodes will be placed to the left and below the left eye. 6 different facial regions will be stimulated. The electrical stimulation will be kept constant during the test sessions. To prevent habituation, the stimuli will be delivered randomly at intervals of 45-60 sec. Four 0.2 msec pulses will be presented. In some cases, paired pulse stimulation will be performed, and a conditioning stimulus will be applied to the target facial regions at the following intervals: 10, 200, 400, 600 and 800 msec. 4 pulses will be presented at each stimulus interval with randomized interval and pulse sequences.; Olfactory testing will be performed using standard tests. The University of Pennsylvania Smell Identification Test (UPSIT) assesses a subjects ability to identify odors in a forced choice format. The Snap and Sniff Threshold Test provides a threshold measure of phenyl ethyl alcohol. Short-term odor memory will be assessed using a standardized 12-item four-alternative forced-choice Odor Memory Test. This non-lexical test employs 10-, 30-, and 60-second delay intervals between the presentation of the target odorant and the first of four successively presented odors from which the target is to be selected.; During a 2-hour visual deprivation period, subjects will wear comfortable light-tight goggles with lenses that have been blackened by flat black paint. Subjects will be given the opportunity to recline comfortable in a padded reclining chair during this time.; Electrical stimulation will be applied to a nerve of your arm. Sticky electrode pads will also be placed on a hand muscle. You will receive electrical stimulations that lasts less than a second. The stimulations will make your muscle twitch.
Other intervention name(s): Electromyography; Repetitive Nerve Stimulation
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Normal controls and patients with such neural disorders as Parkinson's Disease(PD),
        Alzheimer's disease (AD), progressive supranuclear palsy (PSP), essential tremor (ET),
        dementia with Parkinson's disease (D-PD), myasthenia gravis (MG), multiple system atrophy
        (MSA), diffuse Lewy body disease (DLBD), and Spinal Cord Injury (SCI). None will be
        cigarette smokers. The patients will be diagnosed accord to current consensus criteria. The
        healthy controls will be matched to the PD patients on such variables as sex, age,
        education level, and ethnicity. The Healthy Controls will be asked to answer questions
        regarding the disease state of their first degree family members to ensure that these first
        degree family members do not have a neurodegenerative diseases. Every effort will be made
        to include women and minority subjects.