The inquiry into the recall of patients of suspended neurologist Dr Michael Watt has so far received 23,000 pages of evidence.
Politicians yesterday attended a cross-party briefing by the independent neurology inquiry, which was set up by the Department of Health.
Last May officials revealed they were contacting around 2,500 health service patients and just over 110 private patients after concerns were raised about the consultant's work.
Last October it was announced that an additional 1,044 former patients would also be recalled.
The inquiry, chaired by Brett Lockhart QC, is reviewing the recall of neurology patients by the Belfast Trust.
SDLP deputy leader Nichola Mallon was among those who attended yesterday's briefing.
Those present heard that more than 160 responses to a patient questionnaire had been received, with 48 witnesses having already been seen by the panel.
Around 60 more witnesses are yet to appear, while 23,000 pages of evidence are being scrutinised.
Ms Mallon said: "It was reassuring to hear from the panel that patients' voices will be heard in their final report and recommendations.
"As the only investigation into this scandal that has given a platform to patients, this is critically important.
"It is vitally important that all aspects of this investigation are followed through in a timely and robust manner."
The inquiry is investigating the circumstances leading to the patient recall for the period between November 2016 and May 2018, and to evaluate corporate governance procedures within the Belfast Trust.
The probe will also review the trust's handling of relevant complaints or concerns identified or received prior to November 2016, and participation in processes to maintain standards of professional practice, including appraisals. Earlier this month Dr Watt was suspended from practice following a hearing by the Medical Practitioners Tribunal Service.