​​​​​​eRiver Neurology of NY 


Dedicated Physicians, Nurses, Technologists and Office Staff


For 12 years, eRiver Neurology of NY has built a reputation of caring and professionalism in the Hudson Valley of NY.  We have nurtured the growth of Epilepsy Care, Stroke Care and Pediatric Neurology care throughout the region.  We have developed innovative programs and technologies in our 4 offices and at multiple hospitals with the region.  Above all, we are proud to provide highly experienced and compassionate doctors to serve our community.

Jess Collins MD

Dr Collins is Board Certified in Neurology and Clinical Neurophysiology with fellowship training in Clinical Neurophysiology. 


Samuel Koszer MD

Dr Koszer is the managing partner and founder of eRiver Neurology.  He has more than 25 years of experience as a neurologist with expertise in difficult to treat epilepsy, parkinsons disease and MS . He is Board Certified in Neurology and in Clinical Neurophysiology.

Office Manager

Kathy Ryan

About us


David Ryan, EEGT

Joyce Tuller , EEGT

​Lisa Fox, EEGT

Dee DEE Girgenti, REEGT

Our Mission

To provide the expertise and resources for Comprehensive Epilepsy, Stroke, Pediatric and General Neurologic care to the Hudson Valley of New York.

Rose Mathew DO

Dr Mathew is Board Certified in Neurology with fellowship training in Neuro-Oncology.  She has more than 15 years experience and evaluates and treats all types of neurologic disorders.

Glenn Y Castaneda MD

Co-founder of eRiver Neurology and Pediatric Neurologist for more than 25 years.  Dr Castaneda is board certified in Neurology with special qualifications in pediatric neurology.  He has expertise in treating newborns to adolescent children with epilepsy, developmental issues, and all general neurologic problems.






 Samuel Koszer MD

Glenn Castaneda MD

Alex Safarov MD

Rose Mathew DO

Jess Collins, MD

Kathryn McDonell DNP, FNP

Jillian Jones, NP

David Ryan, EEGT

Joyce Tuller, EEGT

D.D. Girgenti, REEGT

Nancy Matteo, Research, LPN

Kathy Ryan, Office Manager

who we are

Alexandr Safarov MD 

Board Certified in Neurology and Clinical Neurophysiology and fellowship trained. Dr Safarov has been in practice for more than 20 years and sees adult neurology patients.  He is experienced as a clinician and also in electrodiagnositic testing

Nurse Practitioner

Kathryn McDonell, DNP, FNP-BC

Jillian Jones, NP