. 2020 Aug 11;1(1):63–72. doi: 10.1089/neur.2020.0017

Table 3.

Item-level Rasch Model Fit Statistics for the Initial Analysis of the 16-item RPQ with Item Locations, Fit Residuals, Chi-Square Statistics, and % of Participants Endorsing Symptoms by Response Category and Injury Group

							% Endorsing symptom category
		Location	SE	Fit Resid	χ²	Prob	TBI					Orthopedic					Sig^a
	RPQ item	Location	SE	Fit Resid	χ²	Prob	0	1	2	3	4	0	1	2	3	4	Sig^a
1	Headaches	-0.17	0.10	0.08	7.54	0.581	37	47	9	4	4	72	20	4	4	0	0.000^*
2	Feelings of dizziness	0.65	0.12	-0.31	5.86	0.754	36	50	11	3	0	76	21	1	2	0	0.000^*
3	Nausea and/or vomiting	1.54	0.15	1.03	5.49	0.790	56	42	2	0	0	76	23	1	0	0	0.009^*
4	Noise sensitivity, easily upset by loud noise	0.16	0.10	-1.68	8.54	0.480	48	34	10	6	2	86	10	3	2	0	0.000^*
5	Sleep disturbance	-0.44	0.08	2.86	27.43	0.001	50	24	6	16	5	46	40	5	8	0	0.571
6	Fatigue, tiring more easily	-0.87	0.09	-0.26	15.23	0.085	21	40	14	22	3	40	38	11	8	3	0.024^*
7	Being irritable, easily angered	-0.52	0.09	-0.80	3.28	0.952	37	36	8	14	6	59	28	9	3	2	0.003^*
8	Feeling depressed or tearful	-0.13	0.09	-0.40	5.24	0.813	45	32	12	9	2	64	27	4	4	1	0.006^*
9	Feeling frustrated or impatient	-0.80	0.09	-1.33	8.72	0.464	22	42	16	14	6	40	46	8	4	1	0.001^*
10	Forgetfulness, poor memory	-0.53	0.09	-0.77	7.33	0.602	19	36	21	18	6	76	12	6	5	0	0.000^*
11	Poor concentration	-0.30	0.09	-2.88	14.85	0.095	38	32	12	13	6	75	17	4	4	0	0.000^*
12	Taking longer to think	-0.52	0.08	-2.80	11.34	0.253	28	31	18	16	6	72	19	4	4	1	0.000^*
13	Blurred vision	0.56	0.11	0.41	13.43	0.144	71	19	5	5	1	85	11	3	1	0	0.032^*
14	Light sensitivity, easily upset by bright light	0.79	0.11	-0.32	8.15	0.519	61	29	6	5	0	84	10	3	4	0	0.001^*
15	Double vision	0.91	0.18	-0.86	5.08	0.828	81	17	0	1	1	96	4	0	0	0	0.002^*
16	Restlessness	-0.32	0.09	0.50	21.49	0.011	48	30	12	6	5	60	32	6	2	1	0.091

0 = not experienced at all; 1 = no more of a problem; 2 = mild problem; 3 = moderate problem; 4 = severe problem.

^{^*}

Denotes statistical significance at p < 0.05.

^{^a}

Mann-Whitney U test for comparing mean rank ordinal scores for TBI and orthopedic groups at individual item-level.

Bold indicates significant misfit to the Rasch model.

RPQ, Rivermead Post-Concussion Symptoms Questionnaire; SE, standard error; TBI, traumatic brain injury.