Siobhan Mark , MS CCC-SLP
Speech-Language Pathologist • Walnut Creek, CA
320 Lennon Ln
Walnut Creek, CA 945982419
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
Practice Location & Contact Primary Location
320 Lennon Ln
Walnut Creek, CA 945982419
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
NPPES lists 1 additional practice-address record in Walnut Creek, CA. See the list
Source: CMS NPPES NPI Registry, practice location records; release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
What Public CMS Data Show
Speech-Language Pathologist: NPPES taxonomy is a reported classification, not proof of board certification.
NPI first issued
2018
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, “Does your provider accept Medicare as full payment?”
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Enrolled in Medicare (PECOS)
Siobhan Mark has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Walnut Creek and California
61 active clinicians are listed under Speech-Language Pathologist with a practice address in Walnut Creek, CA (13,149 in California).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Walnut Creek
0% of these 61 clinicians have the CMS telehealth indicator.
3.3% of these 61 clinicians are listed by CMS as accepting Medicare assignment.
Sources: CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo · Report an error.
Specialties & License Numbers Reported to NPPES
NUCC Taxonomy Code: 235Z00000X
The speech-language pathologist is the professional who engages in clinical services, prevention, advocacy, education, administration, and research in the areas of communication and swallowing across the life span from infancy through geriatrics. Speech-language pathologists address typical and atypical impairments and disorders related to communication and swallowing in the areas of speech sound production, resonance, voice, fluency, language (comprehension and expression), cognition, and feeding and swallowing.
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - QUALIFIED SPEECH LANGUAGE PATHOLOGIST
I20221122001390
CA
0648648782
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Secondary Practice Locations
1425 S Main St
Walnut Creek, CA 945965318
Phone: 9252954000
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Ophthalmology
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Allergy & Immunology
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Career & Practice History
NPI enumerated April 19, 2018.
No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from May 2018 to August 2026.
NPI Administrative Meta
Mailing Address
1242 Spruce St
Berkeley, CA 947091433
Phone: 5103236946