Health officials have missed their deadline to double the number of nurses specialising in motor neurone disease (MND).
First Minister Nicola Sturgeon personally promised the expansion in response to a campaign by the MND patient Gordon Aikman.
Mr Aikman's story featured in a BBC documentary, which was broadcast on Monday.
The charity MND Scotland said it was "frustrated" by the lack of progress.
It's a year since Ms Sturgeon committed £2.5m to improve specialist nursing care.
This included cash for the NHS to replace charity funding for MND nurses and for their number to increase from six to 12.
Scotland's chief nursing officer gave health boards until the end of October to deliver. However, no new nurses were in post by then.
'Dragging their heels'
NHS Greater Glasgow and Clyde has since recruited. NHS Highland has advertised and, in other areas, the hours worked by existing nurses have been increased.
MND Scotland called for further action on the issue in Grampian, Tayside, Lothian, Forth Valley and Fife
The charity's chief executive, Craig Stockton, told BBC Scotland: "There's a growing sense of frustration from our point of view in that at this current time we still have no more new nurses in place. Not a single one.
"What has happened is that existing nurses who were on part time contracts have had their hours increased.
"I don't know if it's dragging their heels but they're certainly taking their time to put these posts in place."
He added: "It was meant to have happened by the 31st of October. That was the deadline.
"We're asking questions just now about the money side of things. What we think has happened is it's been absorbed by the health boards."
The charity has written to Health Secretary Shona Robison.
In a statement, she said: ""The Scottish government recognises the vital role specialist nurses play in patient care.
"The funding for MND specialist nurses was allocated to relevant health boards in June 2015. It is then for individual health boards to plan and deliver services to meet the needs of their local community.
"The health boards involved are currently in the process of recruiting additional nurses, or increasing the hours of existing nurses in order to fulfil our pledge to double the number of MND nurses in Scotland.
"Some posts have already been filled, with nurses due to start in January, the remaining posts are expected to be filled by spring 2016."