Parkinson's is a degenerative condition that affects the brain
Some Parkinson's disease patients are going for years without seeing a specialist doctor or nurse, according to a parliamentary report.
The All Party Parliamentary Group for Parkinson's Disease heard from hundreds of patients and care organisations.
Its inquiry found inequalities in access to care and discrepancies across the country - with serious shortfalls in Wales and Northern Ireland.
It urged a thorough review of services to ensure patients get what they need.
Parkinson's disease is a chronic neurological condition which affects around 120,000 people in the UK. It disturbs the way the brain co-ordinates body movements, including walking, talking and writing.
Parkinson's 'tsar' in government
Monitoring of Parkinsons services
Ensuring enough qualified staff in place
Access to specialist doctors has been a problem across the country, but the inquiry heard that in Northern Ireland there is not a single consultant with expertise in Parkinson's.
Appointments with specialists were crucial, experts warned, particularly given the high rate of misdiagnosis and the subsequent implications for treatment.
Many people with Parkinson's and their carers told the panel of MPs and peers how much they valued the services of specialist nurses.
But despite research suggesting these nurses saved the NHS money by cutting down hospital visits and providing support in the home, there were "sizable shortfalls".
Some people in Wales, for example, had no access at all to a nurse, while others had to travel to Liverpool for help.
Meanwhile treatments were restricted in some areas. Deep Brain Stimulation (DBS) is seen as an effective way of improving physical ability and reducing tremors, but the inquiry reported examples of trusts with no, or very limited funding for the procedure.
Provision of speech and language therapy was also found to be seriously wanting, particularly for those living away from major hospital centres.
Again there were significant regional variations. In the north west of England, the proportion of people who had never had an assessment or course of therapy - be it diet, physio, or speech and language - was higher than in the rest of the country.
Carers also reported a lack of support, with many describing a "feeling of abandonment and loneliness".
Steve Ford, Chief Executive of the Parkinson's Disease Society said: "The report uncovers just how bad services are for so many people with Parkinson's. This needs to change.
"We want to see effective monitoring of Parkinson's services to ensure they meet national guidelines and standards, an urgent review of the health and social care workforce, and stronger national and local leadership by government.
"Why is it that some conditions have these - for example a 'tsar' within government - and other conditions like Parkinson's don't?"
Baroness Gale, chair of the APPG for Parkinson's Disease said: "We hope that the APPG Inquiry report released today will provide the boost to the UK government and the devolved administrations in Wales and Northern Ireland to reprioritise Parkinson's and to deliver against the report's recommendations."
Health Minister Ann Keen said medical staff in the field of neurology had increased by more than 50% since 1997 and that guidelines on how to establish multi-disciplinary neurological teams had been published by the Department of Health.
"These measures, along with the continual work we are doing with local health and social care communities and the third and voluntary sector, will help people with Parkinson's disease to manage their condition and maintain their independence and quality of life."