Welcome to the forum. Has your Mum been advised to keep a medication diary? It's an extremely good way of monitoring your response to medication throughout the day and pinpointing problems.Keeping a medication diary helps in communicating with doctors. Make sure to note when medication is taken, ON and OFF times (ON is when symptoms are relieved and OFF is when symptoms return), and how long each ON and OFF period lasts. Record this information for a few days and then share it with the doctor.
The times of day when your Mum has good symptom control
Which symptoms come back during the day and when (eg, grinding teeth, painful leg, urine frequency, feeling anxious, low mood, rigidity, slow movement, tremor etc
The symptoms she experiences at night (eg, sleep disturbances, teeth grinding, sweating, visits to the toilet etc)
Mealtimes, to see if the times of day she eats affect her symptom control
A diary will give the doctor a picture of life outside the doctor’s office. It will also let him or her track progress and any changes in medications, and will provide a long-term record to look back on
Example of a diary which you can also print http://zelapar.com/Portals/31/skins/zelapar/images/med_diary_dl.pdf
Here are a few more links you might find useful and will answer some of the questions you have asked about 'right diagnosis' and why people with PD have are prescribed different medication.http://www.parkinsons.org.uk/PDF/FS94_Parkinsonsandtremor.pdfhttp://www.parkinsons.org.uk/PDF/FS48_diagnosingParkinsons.pdfhttp://www.parkinsons.org.uk/PDF/B013_drugtreatmentsforparkinsons.pdfhttp://www.parkinsons.org.uk/PDF/FS43_Musclecrampsanddystonia.pdfhttp://www.parkinsons.org.uk/PDF/FS73_MotorFluctuationsinParkinsons.pdfhttp://www.parkinsons.org.uk/PDF/FS40_skinscalpsweating.pdf
I know that's quite a lot of info to throw at you, however, understanding the symptoms of PD and reading up about the different drug options, for me is the key to controlling this disease.
I think your Mum's specialist is right in suggesting adjusting medication and a medication diary would be a good way of monitoring your Mum's response. It's trial and error with the drug treatments of Parkinson's and no two people with Parkinson's are the same in the way Parkinson's presents itself (it's known as a designer disease) and their response to medication. This is why different medication are prescribed and tailored to the individuals needs.
As Dave suggests, do give the Parkinson's UK Hotline a call. It's an excellent service that provides professional advice and support through fully trained Parkinson's Nurses.