Quality Categories	Ratings
	High	Moderate	Low
Design	Single-subject across participants; relatively large group (i.e., >10)	Single-subject 1 participant; small group (i.e., <10)	Case study
Control for confounding factors	Adjustment for at least 3 confounding factors (e.g., ethnocultural background, gender), including age and education	Adjustment for at least age and education	Adjustment for 1 or 0 confounding factors
Aphasia variables	Specification of aphasia severity and description of language profile; range of aphasia profiles included	Specification of aphasia severity and description of language profile; restricted range of aphasia profiles included (e.g., only mild aphasia)	Specification of presence of aphasia but limited description of language profile
Assessment variables	Specification of assessor qualifications AND assessment conditions (e.g., same assessor across testing sessions; tested in quiet room) sufficient to allow replication	Specification of assessor qualifications OR assessment conditions sufficient to allow replication	No specification of assessment variables
STM/WM test interpretation	Reference standard for the STM/WM test score(s) specified (e.g., compared to appropriate control group; utilised standard scores)	Reference standard for the STM/WM test score(s) specified	No specification of reference standard

This Study Quality Rating Tool is based on information in NIHR York University Guidelines and Criteria for Appraising Diagnostic Test Studies; Khan et al. (2003), STARD and COSMIN checklists. A study must score high in 4 out of 5 categories for an overall High rating (with no low rating); an overall moderate rating for a study cannot include any low rating.