A Study To Evaluate The Difference In iPad-Based Cognitive Video Game (Akili Interactive's Project: EVO) Performance In Amyloid-Positive Versus Amyloid-Negative Healthy Elderly Volunteers

• Drug: Ritalin
  
  1 - 20 mg tablet taken once on Day 0 and taken once on Day 28
  Other Name: methylphenidate hydrochloride 20mg tablet taken once on day 0 and once on day 28
• Drug: Placebo
  
  1 - matching tablet taken once on Day 0 and once on Day 28
  Other Name: matched placebo tablet taken once on day 0 and once on day 28

• Active Comparator: (Amyloid Negative)
  
  Interventions:
  

  • Drug: Ritalin
  • Drug: Placebo
• Active Comparator: Amyloid Positive
  
  Interventions:
  

  • Drug: Ritalin
  • Drug: Placebo

Inclusion Criteria:

• Healthy males and females between the ages of 70 and 80.
• Subjects must have BMI of 17.5 to 32 kg/m2 and total body weight > 110 pounds.
• Acceptable screening MRI and PET scans that pass quality control requirements.

Exclusion Criteria:

• Co-morbid diagnosis of clinically documented Alzheimer's disease; - Significant cognitive impairment;
• MMSE (mini mental state examination) score <26