Cognitive Dysfunction in Postural Tachycardia Syndrome

• Standing Digits Backwards Test [ Time Frame: In the standing position for approximately 15 minutes. This is a cross-sectional study with no follow-up. ] [ Designated as safety issue: No ]
  This is a continuous variable that will provide a measure of attention with orthostatic stress.
  
  

• Cognitive Domain Score (CDS) [ Time Frame: At seated and standing. This is a cross-sectional study without follow-up. All assessments are performed on a single day. ] [ Designated as safety issue: No ]

  The CDS will consist of

  1: Seated memory (Randt Short Story subtes, Paired words subtes and Digits Forward) and standing memory (Randt short story, paired words and digits forward).

  2. Seated Complex Attention (Ruff, SDMT, Trails A, Randt, Digits Backward) and standing complex attention (Randt digits backward) 3. Executive functioning only while standing (Stroop, Trails) 4. Seated and standing verbal fluency (COWA).

  
  

Postural Tachycardia Syndrome (POTS) is a disorder that affects an estimated 500,000 people in the United States alone and is an important source of disability in young adults. It shows a strong predilection for females. POTS is a form of orthostatic intolerance characterized by an excessive increase in heart rate (>30 bpm) on assuming the upright position associated with orthostatic symptoms, but in the absence of orthostatic hypotension. Their symptoms of dizziness, nausea, tremor, chronic fatigue and exercise intolerance make even simple activities of daily living exhausting prospects.

Brain fog or cognitive dysfunction is a common and almost universal complaint among persons with POTS. There is a lack of pathophysiological understanding to this cognitive dysfunction and is also a major roadblock to the development of effective therapies for people with POTS.

The purpose of this study is to better define the cognitive dysfunction seen in patients with POTS. We will use a series of validated neuropsychological tools in order to characterize POTS cognitive dysfunction and compare this data to age and gender matched control subjects.

Specific Aims:

1. To assess whether POTS patients have more neuropsychological abnormalities than control subjects during seated assessments.
2. To assess whether POTS patients have more neuropsychological abnormalities than control subjects during assessments while standing.
3. To ascertain the phenomenology of any neuropsychological deficits distinguishing POTS patients from controls.