Validity and reliability of a new tool to evaluate handwriting difficulties in Parkinson’s disease

Abstract

BackgroundHandwriting in Parkinson’s disease (PD) features specific abnormalities which are difficult to assess in clinical practice since no specific tool for evaluation of spontaneous movement is currently available.ObjectiveThis study aims to validate the ‘Systematic Screening of Handwriting Difficulties’ (SOS-test) in patients with PD.MethodsHandwriting performance of 87 patients and 26 healthy age-matched controls was examined using the SOS-test. Sixty-seven patients were tested a second time within a period of one month. Participants were asked to copy as much as possible of a text within 5 minutes with the instruction to write as neatly and quickly as in daily life. Writing speed (letters in 5 minutes), size (mm) and quality of handwriting were compared. Correlation analysis was performed between SOS outcomes and other fine motor skill measurements and disease characteristics. Intrarater, interrater and test-retest reliability were assessed using the intraclass correlation coefficient (ICC) and Spearman correlation coefficient.ResultsPatients with PD had a smaller (p = 0.043) and slower (p<0.001) handwriting and showed worse writing quality (p = 0.031) compared to controls. The outcomes of the SOS-test significantly correlated with fine motor skill performance and disease duration and severity. Furthermore, the test showed excellent intrarater, interrater and test-retest reliability (ICC > 0.769 for both groups).ConclusionThe SOS-test is a short and effective tool to detect handwriting problems in PD with excellent reliability. It can therefore be recommended as a clinical instrument for standardized screening of handwriting deficits in PD.

Levodopa improves handwriting and instrumental tasks in previously treated patients with Parkinson’s disease

“…The collected data of the handwriting scenario in our present trial mainly assess writing velocity only. We stress that handwriting also asks for readability in the specific investigational situation, which is considerably influenced by precise trajectories with their considerable impact on size of letters, speed, and fluency of writing (Nackaerts et al 2017a , b ). Coordinated performance and accurated performance of motion sequences are characteristics, which are also important for the execution of the peg insertion test.…”

“…Similar cognitive efforts with a hypothetical involvement of resembling brain structures are necessary when one writes a sentence (Gangadhar et al 2009 ). It is well known that not only micrographia, which is abnormal small, cramped handwriting or the progression to progressively smaller handwriting, but also bradykinesia and rigidity influence the handwriting procedure in PD patients (Lalonde et al 1997 ; Nieoullon et al 2003 ; Lange et al 2006 ; Broeder et al 2014 ; Nackaerts et al 2017b ). To a certain extent, a resembling instrumental task is the performance of a line tracing task, which asks the individual to follow a given path (Fig.…”

Training for Micrographia Alters Neural Connectivity in Parkinson's Disease

“…The distance between the bottom of the blue and top of the yellow target zone was 0.6 cm. The cued writing task was performed in the presence of these colored target zones, while in the uncued condition the target zones disappeared after 1.5 s. To assess daily life handwriting, we used the “Systematic Screening of Handwriting Difficulties (SOS)” test, involving writing a text on paper for 5 min continuously (Nackaerts et al, 2017 ).…”

“…Mean writing size (mm) and writing velocity (letters written in 5 min) were determined. The total SOS-score, representing quality, was determined and consisted of: (i) fluency of letter formation; (ii) fluency in connections between letters; (iii) regularity of letter height; (iv) space between words; and (v) straightness of the sentences (Nackaerts et al, 2017 ). A higher total SOS-score indicated worse quality of handwriting (0–10).…”

Derivation and Analysis of Dynamic Handwriting Features as Clinical Markers of Parkinson’s Disease

“…Research to date has focused on digitizing established drawing tasks for assessing cognitive impairment, including: signature writing [11,14], writing short phrases [15], pentagon copying [16][17][18], clock drawing [19], spiral drawing [20][21][22], circles and cursive looping [23,24]. Of these, writing words and phrases containing repetitions of cursive 'l' and 'e' have been commonly reported [25][26][27]. However, writing is influenced by culture, penmanship training, level of education and linguistic ability [28].…”