Table 1.

Subject characteristics and skeletal muscle histology

	Parkinson’s Disease	Older Adults	Young Adults
Subjects, n	12 (9 M/3 F)	12 (9 M/3 F)	12 (9 M/3 F)
Age, yr	67 ± 2	68 ± 2	30 ± 1
Parkinson’s disease progression
Time since diagnosis, yr	6 ± 1
Hoehn and Yahr stage	2 (n = 8), 3 (n = 4)
Levodopa equivalency dose, mg/day	511 ± 133
MDS-UPDRS motor score	30 ± 3
PDQ-39 total score	24 ± 7
PDQ-39 mobility subscore	13 ± 4
Myofiber distribution, %
Type I	49 ± 5*	35 ± 2	33 ± 2
Type IIa	36 ± 5†	49 ± 4	54 ± 3
Type IIx	14 ± 4	17 ± 4	13 ± 2
Type II (combined)	51 ± 5*	65 ± 2	67 ± 2
Type I myofiber grouping
Mean group size, type I myofibers/group	187 ± 73*	14 ± 3	13 ± 2
Standard deviation, type I myofibers/group	121 ± 63	12 ± 5	9 ± 2
Minimum group size, type I myofibers/group	26 ± 11*	5 ± 1	6 ± 1
Maximum group size, type I myofibers/group	224 ± 99*	32 ± 10	34 ± 8
Frequency, no. of type I groups/1,000 myofibers	3 ± 1§	6 ± 1	7 ± 1
Percentage of grouped type I myofibers, % total type I myofibers	51 ± 10‡§	22 ± 4	28 ± 5

Values represent means ± SE. Parkinson’s disease progression was not assessed for healthy groups. F, female; M, male; MDS-UPDRS, Movement Disorder Society Unified Parkinson’s Disease Rating Scale (Section III); PDQ-39, Parkinson’s Disease Questionnaire (39 items).

^*P < 0.05 vs. other cohorts;

^†P < 0.05 vs. young adults;

^‡P < 0.05 vs. older adults;

^§P < 0.10 vs. young adults.