J Neurol Res

Journal of Neurology Research, ISSN 1923-2845 print, 1923-2853 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Neurol Res and Elmer Press Inc

Journal website http://www.neurores.org

Original Article

Volume 8, Number 3, November 2018, pages 26-33

Handwriting at Different Paces and Sizes With Visual Cues in Persons With Parkinson’s Disease

Figure 1. (a) Picture of experimental set up. (b) Experimental design. (c) Example handwriting at the 2 cm target size from a person with PD. The top row is the fast condition; the bottom row is the self-selected condition. (d) Example of the digital representation of handwriting.

Figure 2. (a) Letter height for both groups at both paces (fast and self-selected) and both sizes (1 cm and 2 cm). (b) Letter width for both groups at both paces (fast and self-selected) and both sizes (1 cm and 2 cm). Standard error bars shown. Long horizontal bars show within group differences; the short horizontal bars show between group differences. *P < 0.05, ***P < 0.001, ****P < 0.0001.

Figure 3. (a) Difference between perceived stress for self-selected and fast pace conditions. Standard error bars shown. Long horizontal bars show within group differences; the short horizontal bars show between group differences. ***P < 0.001. (b) Perceived stress vs. height scatter plot. (c) Perceived stress vs. peak FDI EMG scatter plot. (d) Perceived stress vs. FDI EMG scatter plot.

**Table 1.** Means and Standard Deviations for All Outcome Variables at Both Sizes and Both Paces
	1 cm	2 cm
For within subjects pace comparisons at either size (1 cm or 2 cm), P < 0.05, P < 0.01, **P < 0.001. For between subjects’ comparisons for a particular size (1 cm or 2 cm) and pace (self-selected or fast), ^†P < 0.05, ^††P < 0.01, ^†††P < 0.001. Acc: acceleration; EDC: extensor digitorum communis; FDI: first dorsal interosseus; HOAs: healthy older adults; PD: persons with Parkinson’s disease; MT: movement time.
PD height (mm)	8.1 ± 1.1	7.9 ± 1.1^†††	15.2 ± 3.2***^,†	13.8 ± 3.2***^,†††
HOA height (mm)	8.8 ± 0.7*	9.3 ± 0.5*^,†††	17.1 ± 1.4^†	16.7 ± 1.1^†††
PD width (mm)	4.8 ± 1.1^†††	4.6 ± 1.3^†††	7.7 ± 2.3^†††	7.1 ± 2.5^†††
HOA width (mm)	6.5 ± 1.2^†††	7.2 ± 1.1^†††	11.1 ± 2.5^†††	11.7 ± 2.2^†††
PD letters completed	10.4 ± 5.2***	15.2 ± 6.2***	12.4 ± 5.4***	17.2 ± 6.5***
HOA letters completed	12.2 ± 4.3***	17.5 ± 6.2***	14.3 ± 4.6***	20.8 ± 6.4***
PD MT (s)	1.5 ± 0.7***	1.1 ± 0.5***^,†	1.9 ± 0.9***	1.2 ± 0.6***
HOA MT (s)	1.1 ± 0.4**	0.8 ± 0.3**^,†	1.4 ± 0.5***	1.0 ± 0.4***
PD peak Acc (m/s²)	7.5 ± 2.3	7.7 ± 2.0^†	8.1 ± 4.2*	9.9 ± 4.3*
HOA peak Acc (m/s²)	7.0 ± 1.7*	9.5 ± 2.5*^,†	10.2 ± 3.6	12.5 ± 3.5
PD peak EDC (µV)	80.4 ± 47.0*	88.7 ± 47.3*	85.1 ± 68.7	88.9 ± 54.9
HOA peak EDC (µV)	63.1 ± 25.8	77.1 ± 53.1	83.4 ± 74.4	71.1 ± 33.9
PD peak FDI (µV)	449 ± 538	456 ± 547	525 ± 625	521 ± 634
HOA peak FDI (µV)	268 ± 182**	340 ± 201**	334 ± 229	318 ± 187
PD area EDC (mV)	0.75 ± 0.38***	0.89 ± 0.47***	0.76 ± 0.55	0.82 ± 0.44
HOA area EDC (mV)	0.69 ± 0.31	0.73 ± 0.31	0.69 ± 0.36	0.69 ± 0.28
PD area FDI (mV)	2.15 ± 2.02	2.62 ± 2.60	2.32 ± 2.12	2.90 ± 2.79
HOA area FDI (mV)	2.78 ± 2.54	3.11 ± 1.89	2.97 ± 1.87	2.67 ± 1.46
PD stress	2.6 ± 1.6***	4.2 ± 2.0***^,†††	2.6 ± 1.6***	4.2 ± 2.0***^,†††
HOA stress	1.6 ± 1.3	1.6 ±1.3^†††	1.6 ± 1.3	1.6 ±1.3^†††

Table 1. Means and Standard Deviations for All Outcome Variables at Both Sizes and Both Paces

1 cm

2 cm

Self-selected

Fast

Self-selected

Fast

For within subjects pace comparisons at either size (1 cm or 2 cm), *P < 0.05, **P < 0.01, ***P < 0.001. For between subjects’ comparisons for a particular size (1 cm or 2 cm) and pace (self-selected or fast), ^†P < 0.05, ^††P < 0.01, ^†††P < 0.001. Acc: acceleration; EDC: extensor digitorum communis; FDI: first dorsal interosseus; HOAs: healthy older adults; PD: persons with Parkinson’s disease; MT: movement time.

PD height (mm)

8.1 ± 1.1

7.9 ± 1.1^†††

15.2 ± 3.2***^,†

13.8 ± 3.2***^,†††

HOA height (mm)

8.8 ± 0.7*

9.3 ± 0.5*^,†††

17.1 ± 1.4^†

16.7 ± 1.1^†††

PD width (mm)

4.8 ± 1.1^†††

4.6 ± 1.3^†††

7.7 ± 2.3^†††

7.1 ± 2.5^†††

HOA width (mm)

6.5 ± 1.2^†††

7.2 ± 1.1^†††

11.1 ± 2.5^†††

11.7 ± 2.2^†††

PD letters completed

10.4 ± 5.2***

15.2 ± 6.2***

12.4 ± 5.4***

17.2 ± 6.5***

HOA letters completed

12.2 ± 4.3***

17.5 ± 6.2***

14.3 ± 4.6***

20.8 ± 6.4***

PD MT (s)

1.5 ± 0.7***

1.1 ± 0.5***^,†

1.9 ± 0.9***

1.2 ± 0.6***

HOA MT (s)

1.1 ± 0.4**

0.8 ± 0.3**^,†

1.4 ± 0.5***

1.0 ± 0.4***

PD peak Acc (m/s²)

7.5 ± 2.3

7.7 ± 2.0^†

8.1 ± 4.2*

9.9 ± 4.3*

HOA peak Acc (m/s²)

7.0 ± 1.7*

9.5 ± 2.5*^,†

10.2 ± 3.6

12.5 ± 3.5

PD peak EDC (µV)

80.4 ± 47.0*

88.7 ± 47.3*

85.1 ± 68.7

88.9 ± 54.9

HOA peak EDC (µV)

63.1 ± 25.8

77.1 ± 53.1

83.4 ± 74.4

71.1 ± 33.9

PD peak FDI (µV)

449 ± 538

456 ± 547

525 ± 625

521 ± 634

HOA peak FDI (µV)

268 ± 182**

340 ± 201**

334 ± 229

318 ± 187

PD area EDC (mV)

0.75 ± 0.38***

0.89 ± 0.47***

0.76 ± 0.55

0.82 ± 0.44

HOA area EDC (mV)

0.69 ± 0.31

0.73 ± 0.31

0.69 ± 0.36

0.69 ± 0.28

PD area FDI (mV)

2.15 ± 2.02

2.62 ± 2.60

2.32 ± 2.12

2.90 ± 2.79

HOA area FDI (mV)

2.78 ± 2.54

3.11 ± 1.89

2.97 ± 1.87

2.67 ± 1.46

PD stress

2.6 ± 1.6***

4.2 ± 2.0***^,†††

2.6 ± 1.6***

4.2 ± 2.0***^,†††

HOA stress

1.6 ± 1.3

1.6 ±1.3^†††

1.6 ± 1.3

1.6 ±1.3^†††

**Table 2.** Spearman Partial Correlation Between Perceived Stress and All Other Outcome Variables After Controlling for Group, Size, and Pace
	Perceived stress
P < 0.05. *P < 0.01. ACC: acceleration; EDC: extensor digitorum communis; FDI: first dorsal interosseus; MT: movement time.
Height (mm)	-0.184*	0.036
Width (mm)	0.059	0.504
Letters completed	0.113	0.203
MT (s)	-0.095	0.285
Peak Acc (m/s²)	0.132	0.137
Peak EDC (µV)	0.049	0.579
Peak FDI (µV)	-.250**	0.007
Area EDC (mV)	0 .075	0.4
Area FDI (mV)	-0.241**	0.009

Table 2. Spearman Partial Correlation Between Perceived Stress and All Other Outcome Variables After Controlling for Group, Size, and Pace

Perceived stress

r_s

*P < 0.05. **P < 0.01. ACC: acceleration; EDC: extensor digitorum communis; FDI: first dorsal interosseus; MT: movement time.

Height (mm)

-0.184*

0.036

Width (mm)

0.059

0.504

Letters completed

0.113

0.203

MT (s)

-0.095

0.285

Peak Acc (m/s²)

0.132

0.137

Peak EDC (µV)

0.049

0.579

Peak FDI (µV)

-.250**

0.007

Area EDC (mV)

0 .075

0.4

Area FDI (mV)

-0.241**

0.009