Graphoscopic Evaluation After a Fine Motor Skill Rehabilitation Program in Parkinson’s Disease—Exploratory Study ^†

Abstract

Individuals with Parkinson’s disease often face legal disputes over documents signed before the ongoing disease, since fine motor skill changes can lead to alterations in handwriting. Generally, rehabilitation programs focus on mobility in the lower limbs; however, these individuals also face challenges involving the control of fine motor skills, such as handwriting and maintaining their graphic identity. The aim of this exploratory study is to evaluate the effect of a fine motor skill rehabilitation program on the handwriting of these individuals. This study involved 10 subjects with a diagnosis of Parkinson’s disease, four of whom participated in the rehabilitation program, while the remaining six were allocated to the control group. All participants were instructed to write specific sentences before and after the twelve-week intervention. The main qualitative changes observed between groups after the graphoscopic analysis were in features such as tremors, retouching/overwriting, size, legibility, and line quality.

1. Introduction

Handwriting identification and the determination of authenticity of signatures are complex subjects. However, they become more challenging when the documents are signed by individuals with a neurological condition, such as Parkinson’s disease, since it can lead to inconsistencies in their signature when compared to those executed prior to the disease [1,2]. This disorder can lead to progressive alterations in handwriting due to bradykinesia, tremor, and rigidity, which limit movement, contribute to muscular pain, and compromise the control of fine motor skills [3]. Since handwriting is a skill that requires muscular movements and coordination, these outcomes have an impact on daily challenges. For instance, potential legal implications involving the control of fine motor skills, such as handwriting, and preserving the graphic identity of these individuals [1]. In recent years, there has been growing evidence suggesting that nonpharmacological interventions including different rehabilitative approaches can improve functional activities in individuals with Parkinson’s Disease [4]. However, these studies mainly focus on gait and balance, despite handwriting deficits being very common in Parkison’s Disease. The studies assessing handwriting in individuals with Parkinson’s Disease usually use kinematic analysis or explore modulating factors such as cues, feedback, or dual tasks [5], but only a few studies investigated the effects of a training on handwriting or used specific outcome measures of handwriting in rehabilitation studies [6]. Thus, the aim of this study is to evaluate the effect of a fine motor skill rehabilitation program on the handwriting of individuals with Parkinson’s disease.

2. Materials and Methods

This exploratory study employs a design, as illustrated in Figure 1, involving 10 subjects with a diagnosis of Parkinson’s disease, recruited through Clínica de Fisioterapia Egas Moniz at Monte da Caparica. All participants were fully briefed on the conditions under which they would perform the tests and the rehabilitation program procedures and signed informed consent forms. The collection, processing, and dissemination of data were carried out anonymously. The procedures implemented in this exploratory study were subject to registration in clinicaltrials.gov (NCT06693401), scientific approval by the Egas Moniz Scientific Council, and ethical approval by the EM Ethics Committee (protocol code 1171/2023), in accordance with the Declaration of Helsinki (Declaration of 1975, revised in 2000).

The participants were allocated to the Control Group (CG) or the Intervention Group (IG) according to their convenience. A traditional physiotherapy rehabilitation program (TPRP) (practice for 1h, twice a week) was implemented according to the European Physiotherapy Guideline for Parkinson’s Disease [7,8]. The Occupational therapy rehabilitation program (OTRP) was implemented through workbooks, practice for 30 min, three times a week [9] and the motor tasks, adapted from Aragon & Kings [10], and consists of performing, 2–3 times a week, exercises included in a workbook (drawing the upper and lower case letters of the alphabet guided by dotted lines, writing a sentence with and without spatial limits), and performing 4 groups of fine motor tasks: hand manipulation (2 exercises: (a) hold a dry bean in the palm of the hand, move it to the fingertips and back to the palm of the hand, (b) hold a ping-pong ball in the hand and turn it clockwise and anticlockwise); finger isolation (3 exercises: (a) place the palm and fingers on a table, lift one finger at a time and repeat with all fingers, (b) make an “O” by touching each finger with the thumb, (c) pick up a coin from the table using the thumb and another finger to pinch it, and repeat using each finger); finger flexion and extension (2 exercises: (a) squeeze and release an anti-stress ball, (b) put a rubber band around two fingers at a time and stretch it out); and coordination (1 exercise: do and undo a chain with 10 clips). All exercises were performed 10 times, in triplicate, for each hand.

The forensic handwriting analysis involved a comparison between t0 and t1 within each group in order to identify potential changes that occurred in the subjects’ handwriting over the twelve-week period. Subsequently, an inter-group comparison of the results was carried out to assess the differences in handwriting between the groups, Figure 1.

3. Results

The comparison between the Intervention Group (IG) and the Control Group (CG) revealed that the main qualitative changes observed were in features such as tremors, with a tendency to decrease in the IG and to increase in the CG; retouching/overwriting, where a tendency to decrease was observed in the IG and no changes were observed in CG; size, where no tendency was observed in IG, while an increase was observed in CG; and in line quality, where a better legibility and execution of the letters was achieved in the IG, while the legibility and letters execution worsened in CG. The results of all the comparisons carried out are presented in

Table 1. Results of the comparisons of IG and CG handwriting features after the fine motor rehabilitation program.

Features	Intervention Group—IG	Control Group—CG
Tremor	Decreased	Increased
Retouching/ Overwriting	General decrease	Inconsistent (no changes, decrease, and increase)
Size	Inconsistent (decrease and increase)	Increase
Pen Lifts	Mostly no changes	Mostly no changes
Calligraphic box	Sinuous	Sinuous
Baseline	Inconsistent (horizontal, descending, and ascending)	Inconsistent (horizontal and descending)
Slant	Mostly mixed	Mostly mixed
Legibility	Better Legibility	Worse Legibility
Line Quality	Better line quality in letter execution	Worse line quality in letter execution

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The reduced sample size and convenience-based recruitment constitute a clear limitation which does not allow the study results’ extrapolation, although they validate the methodology and experimental design. While these findings offer valuable preliminary insights, future work should include a larger and heterogeneous sample to ensure greater validity and applicability of the research’s results.

4. Conclusions

These preliminary results suggest that individuals with Parkinson’s disease engaging in a handwriting rehabilitation program can improve their graphomotor skills, which will promote the recovery of handwriting performance and graphic identity.

In future work, a larger sample size would be desirable to validate these results and to enhance the characterization of variability in Parkinson’s disease handwriting.