Table 6.

Interrater reliability of items on the International Paediatric Mitochondrial Disease Scale (IPMDS)

Factor	Basic functioning	ICCagreement	No. = number of patients	Feasibility
1.01	Response to environment	0.670	17
1.02	Exercise capacity	0.701	13	x
1.03	Walking distance	0.847	16
1.04	Tiredness	0.780	16
1.05	Depressed	0.847	12	x
1.06	Epilepsy	0.855	17
1.07	Headache	0.931	12	x
1.08	Muscle pain	0.575	12	x
1.09	Infections	0.581	17
1.10	Chewing	0.942	17
1.11	Swallowing	0.886	17
1.12	Hearing	0.762	17
1.13	Communicating	0.953	16
1.14	Vomiting	0.972	17
1.15	Gastroesophageal reflux	0.962	15
1.16	Constipation	0.833	17
1.17	Diarrhoea	0.976	16
1.18	Cognitive functioning	0.635	15
1.19	Behavioural problems	0.443	16
1.20	Autistic features	0.661	11	x
1.21	Breathing subjective	0.934	15
1.22a	Continence day	0.725	14
1.22b	Continence night	0.725	14
1.23a	Strabismus when tired	0.736	15
1.23b	Ptosis when tired	0.573	15
1.23c	Dysarthria when tired	0.838	13	x
2.01	Growth	0.944	15
2.02	Weight	0.751	15
2.03	Alertness	NV	17
2.04	Breathing	0.740	17
2.05	Dysarthria	0.901	12	x
2.06	Ptosis	0.553	17
2.07	Strabismus	0.82	16
2.08	Eye movements	0.691	16
2.09	Nystagmus	0.925	16
2.10	Vision	0.343	11	x
2.11	Proximal muscle power	0.913	15
2.12	Distal muscle power	0.738	14
2.13	Hypokinesia	0.306	14
2.14	Abnormal movements	0.884	16
2.15	Ataxia	0.858	14
2.16	Tremor	0.864	15
2.17	Reflexes	0.312	16
2.18	Hypertonia	0.649	17
2.19	Hypotonia	0.470	17
2.20	Rigitidy	0.597	17
2.21a	Vibration	0.231	11	x
2.21b	Subtle touch	NV	11	x
3.01	Communicating	0.957	17
3.02	Head control	0.983	17
3.03	Rolling over	0.985	16
3.04	Sitting up	0.963	17
3.05	Sitting up	0.984	17
3.06	Standing up	0.979	17
3.07	Standing	0.974	17
3.08	Walking	0.989	17
3.09	Running	0.968	13	Only >6 years
3.10	Hopping	0.954	13	Only >6 years
3.11	Reaching	0.964	16
3.12	Grasping	0.949	16
3.13	Rotating	0.985	14	Only >6 years

ICC _agreement median intraclass correlation coefficient for agreement between raters per IPMDS item: ≥ 0.7 good agreement are in bold; ≤0.3 poor agreement is in italic x feasible in <80 % of participants, NV no variance