Recruitment Experiences in randomized trial examining vision rehabilitation

It is widely recognised that recruitment to any randomized controlled trial (RCT) evaluating rehabilitation interventions can be challenging andtypically Mini-Mental State Examination (MMSE)[1] scores are an inclusion criterion in therapy trials. We commenced an RCT to examine the effectiveness of a vision rehabilitation strategy for people with hemianopia following stroke, recruited between 1st March 2008 and 7th August 2009 from 6 sites in Adelaide, Australia. The study is registered with the Australian Clinical Trials Registry, Registration Number: ACTRN12610000494033. A total of 3019 people with stroke were admitted to the referring sites over the recruitment period and the number referred for screening for the project was 113, of which 34, a mere 30%, were eligible. Seventy-four were not eligible and 5 were unable to be screened to determine eligibility. There were a number of reasons for not being eligible. Firstly, a high proportion (43.3%) were found not have a hemianopia on screening. The screening test was performed with the direct confrontation method by a research therapist who was trained by a visual specialist [2]. The high false positive screening rate may be attributed to two possibilities. Thefirst is that there was spontaneous resolution of the hemianopia. This natural recovery can occur in up to 50% of people, mostly in the 1st month [3]. This is unlikely as the research therapist screened the patients within two days of referral and automated perimetry with a neuro-ophthamologist was performed within 2 weeks to confirm the hemianopia or otherwise. The second reason is the lack of sensitivity and specificity ofdirect confrontation testing to detect a hemianopia. Several of the patients had a quadrantanopia and were deemed ineligible for the study. Confrontation testing, if performed correctly after the assessor has received training, is valid in determining the presence of hemianopia. There is, however, wide variability in performing confrontation visual field testing [4] with no specified standardization. This can affect the sensitivity in detecting a hemianopia significantly [2]. Secondly, scoring below 24 on the MMSE (n=12, 16.2%) was a common reason for people not meeting the inclusion criteria. A score of twenty-four was chosen as it indicates mild cognitive impairment, to ensure participants could understand the instructions involved in the intervention. This high cut-off score obviously made recruitment more difficult, and is highlighted in the relatively young mean age of those eligible for the study which was 65 years. Thus of the 113 referrals to the vision research project, 30% met theeligibility criteria. For others planning this type of project we would recommend training of clinicians, as well as researchers, in the confrontation test to ensure accuracy. Given the few cases likely to be recruited for a vision rehabilitation study we would suggest inclusion of patients with a lower cognition score to maximise recruitment. 1. Folstein MF, Folstein SE, McHugh PR. Minimental state- a practical method for grading the cognitive state of patients for the clinician. J Psychia Res 1975; 12: 189-198.2.Pandit RJ, Gales K, Griffiths PG. Effectiveness of testing visual fieldsby confrontation. Lancet. 2001 Oct 20;358(9290):1339-40. 3. .Zhang X, Kedar S, Lynn M, Newman N, Biousse B. Natural history of homonymous hemianopia Neurology 2006;66;901-905. 4. Kerr NM, Chew SS, Eady EK, Gamble GD, Danesh-Meyer HV. Diagnostic accuracy of confrontation visual field tests. Neurology. 2010;13;74:1184-1190. Conflict of Interest: None declared