DR. TIMOTHY J O'BRIEN PH.D.
NPI 1275924557
Clinical Neuropsychologist in Fountain Valley, CA
About Dr. Timothy J O'brien Ph.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. TIMOTHY J O'BRIEN PH.D. (NPI 1275924557) is an individual clinical neuropsychologist in Fountain Valley, California, licensed in California (PSY26611) and active in the NPI registry since February 2015. He is enrolled in Medicare PECOS, maintains a secondary practice location in Long Beach, and is a graduate of Other (2012).
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Location 1
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. Timothy J O'brien Ph.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show Timothy O'brien reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Fountain Valley, CA 92708
- Reassigned Medicare billing, California enrollment
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 5
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
FOUNTAIN VALLEY, CA 92708
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Timothy O'brien's NPI number?
The NPI number for Timothy O'brien is 1275924557. It was assigned to this individual provider in the NPPES registry on February 9, 2015.
Where is Timothy O'brien located?
Timothy O'brien practices at 10061 Talbert Ave # 234, Fountain Valley, CA 92708. The listed phone number is (949) 526-9504.
What is Timothy O'brien's specialty?
The primary specialty registered for this NPI is Clinical Neuropsychologist with taxonomy code 103G00000X.
Is Timothy O'brien enrolled in Medicare?
Yes. Timothy O'brien is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for Timothy O'brien's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Timothy O'brien reassigns Medicare benefits to Vision Neuropsychology & Psychology (Fountain Valley, CA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Timothy O'brien's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Timothy O'brien was last updated on November 14, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. Timothy J O'brien, PH.D. · NPI 1275924557
Clinical Neuropsychologist provider in Fountain Valley, California. Individual provider, active in the CMS NPPES registry since February 9, 2015.
## Identity
- **NPI:** 1275924557 (Entity type: Individual)
- **Enumerated:** February 9, 2015
- **Primary specialty:** Clinical Neuropsychologist · taxonomy 103G00000X
- **State license:** PSY26611 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 10061 TALBERT AVE # 234, Fountain Valley, CA 92708-5159
- **Phone:** (949) 526-9504
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment
- **Bills Medicare through:** Vision Neuropsychology & Psychology (NPI 1396631388, Fountain Valley, CA), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2012
## Record status
- **NPPES last updated:** November 14, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1275924557) · Data from the CMS NPPES public registry.