Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Dr. Willaim Allen Decker, PHD

Individual provider Clinical Neuropsychologist · NPI 1033234950

Dr. Willaim Allen Decker, PHD is a Clinical Psychologist in Alexandria, Virginia. Qualified in 1975, 51 years ago. Practices as a sole proprietor, accepts Medicare assignment and offers telehealth. Licensed in Virginia.

Years since qualifying
51
Licensed in
VA
In the registry since
2007
Specialties on file
4
What do these letters mean?
PHD — Doctor of Philosophy
A research doctorate. In healthcare it usually sits alongside a clinical licence.

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Practice location Address checks out

1423 Powhatan St Ste 8
Alexandria, VA 22314-1389
Phone: (703) 836-3678
Fax: (703) 836-2667
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Cognitive & Behavioral Psychologist (primary) Taxonomy 103TB0200X · Licence 0810002331 (VA)
Clinical Neuropsychologist Taxonomy 103G00000X · Licence 0810002331 (VA)
Clinical Psychologist Taxonomy 103TC0700X · Licence 0810002331 (VA)
Health Service Psychologist Taxonomy 103TH0100X · Licence 0810002331 (VA)

Record details

NPI number1033234950
Entity typeIndividual (Type 1)
GenderMale
Credentials PHD
Sole proprietorYes
NPI enumeratedMarch 20, 2007
Last updated in NPPESSeptember 11, 2025
Mailing address1423 Powhatan St, Suite 7, Alexandria, VA 22314-1389

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyCLINICAL PSYCHOLOGIST
Medical schoolOTHER
Graduated 1975 (51 years in practice)
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services

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