Table 4.

Estimated speed–accuracy trade-offs by people with aphasia (PWA), based on differences between simulation fits of actual performance and distance from point of optimal adaptive returns (PAR).

Participant	Response threshold adaptation	Performance at baseline threshold		Performance at PAR		Estimated speed–accuracy trade-off
		Acc (%)	RT (s)	Acc (%)	RT (s)	% ΔAcc	% Δ in RT
PWA10 +	1.3	95	1.33*	93	1.03	2.1	29
PWA11	0.4	97	0.99	96	0.90	0.9	10
PWA12	−1.6*	65*	1.48*	72*	2.61*	−7.0	−43
PWA13	−0.4	89*	1.69*	90*	1.90*	−1.3	−11
PWA14	0.3	87*	1.94*	86*	1.77*	0.5	10
PWA15	0.2	75*	2.08*	74*	1.93*	0.4	8
PWA16 +	3.4*	97	1.71*	95	0.77	2.8	122
PWA18	0.4	93	1.27	92	1.17	1.3	9
PWA19	0.4	91	1.18	91	1.06	0.9	11
PWA20 +	0.7	88*	1.53*	87*	1.21	1.4	27
PWA21 +	2.8*	99	1.34*	96	0.72	2.6	87
PWA22	−0.7	93	1.16	96	1.36*	−3.5	−14
PWA23	0.9	91	1.06	89*	0.82	1.4	29
PWA24 +	1.3	94	1.37*	92	1.00	2.1	37
PWA3 +	1.0	92	1.64*	91	1.29	1.5	27
PWA4	0.0	77*	1.57*	77*	1.57*	0.0	0
PWA5	1.9	94	1.28	91	0.80	2.4	61
PWA6	−0.3	82*	1.80*	83*	1.97*	−1.0	−9
PWA7 a	−1.1*	89*	1.41*	94	1.96*	−5.2	−28
PWA9 +	1.4	95	1.39*	93	1.10	2.5	27

Note. Acc = accuracy; RT = response time.

^*A dependent variable in the impaired range, outside the 95% confidence interval for typical control performance based on the methods of Crawford and Howell (1998). Response threshold adaptation measured as the difference between each participant’s response threshold and their predicted PAR. % ΔAcc was calculated by subtracting the predicted accuracy at PAR from the accuracy at the actual participant threshold. % Δ in RT was calculated by subtracting the predicted RT at PAR from the RT at the actual participant threshold, divided by the predicted RT at PAR.

⁺ Participants with impaired RT performance who would be predicted to perform in the typical control RT range if they set response thresholds at PAR.

^a Participants with impaired accuracy performance who would be predicted to perform in the typical control accuracy range if they set their response thresholds at PAR.