A Method to Assess Hand Motor Blocks in Parkinson's Disease with Digitizing Tablet

Abstract

The non-volitional sudden discontinuation of motor activity, called motor block (MB) or freezing is most commonly associated with Parkinson's disease (PD). MB extends beyond the classical manifestations of PD: akinezia, bradykinezia, rigidity, tremor, and postural instability. MB has been observed and quantified in internally cued repetitive movements such as gait, speech, handwriting, and manual tapping tasks as a distinct feature of PD. We present a simple measurement system for objective evaluation of MB during point-to-point hand movements in patients with PD. Hand trajectories were evaluated in eight PD patients based on values obtained from a digitizing tablet (DT) score. 50 trials per day were recorded in seven consecutive working days. Subjects were instructed to consciously prepare and self-initiate movements between arbitrarily fixed starting and target points without lifting a wireless magnetic mouse. MB was identified as the time interval during movement with no change in coordinates. We analyzed three kinematic parameters: duration, start and number of MBs. If MBs were documented, the DT score was 1, if not, 0. Results were then compared with the ratings of the question in motor section related to freezing of hands from the Unified Parkinson's Disease Rating Scale (UPDRS). For all patients, DT score was in agreement with the UPDRS. Present results indicate that DT is useful for assessing MBs during volitional planar hand movement. This low-cost instrument may be included in a clinical test battery because of short testing time and troublefree preparation of patient.Parkinson's disease; motor block; freezing; digitizing tablet; assessment.Tohoku

From micrographia to Parkinson's disease dysgraphia

“…In a recent meta‐analysis, Planton et al dissociated motor and language‐related processes within a network of cortical and sub‐cortical areas, colloquially referred to as the “handwriting brain”: the left superior frontal sulcus/middle frontal gyrus area and intraparietal sulcus/superior parietal area, and the right cerebellum as primarily writing‐specific areas; the primary motor (M1)/sensorimotor cortices, supplementary motor area, thalamus, putamen, ventral premotor cortex, and posterior/inferior temporal cortex as nonspecific motor or linguistic areas. The depletion of dopamine in the striatum is well established to be at the origin of alterations in motor planning, programming, sequencing, initiation, and execution; assuming the classical cortico‐subcortical circuit models first defined in the early 1990s, many of the “handwriting brain” regions may be affected by PD.…”

Handwriting Impairments in People With Parkinson’s Disease and Freezing of Gait

“…7-9 Furthermore, most previous studies used tasks with limited relevance to daily living. 14,15,17-19 In the current study, handwriting performance was examined because this is a relevant task for most patients. 20 Decreased handwriting size and legibility is often one of the first signs of the disease, and handwriting difficulties have been proposed to be potential biomarkers for early disease detection and subsequent disease progression.…”

Amplitude Manipulation Evokes Upper Limb Freezing during Handwriting in Patients with Parkinson’s Disease with Freezing of Gait

“…Freezing of the upper limbs (FOUL) in PD was investigated previously during a 15 second finger tapping task at maximum speed and during point-to-point hand movements with a magnetic mouse [ 10 , 11 ]. These previous systems classified freezing in the upper limbs based on a lack of change in movement amplitude of at least one second [ 10 , 11 ].…”

“…Freezing of the upper limbs (FOUL) in PD was investigated previously during a 15 second finger tapping task at maximum speed and during point-to-point hand movements with a magnetic mouse [ 10 , 11 ]. These previous systems classified freezing in the upper limbs based on a lack of change in movement amplitude of at least one second [ 10 , 11 ]. Recent studies in gait, however, indicate that freezing is not always characterized by a complete cessation of movement, but rather by a lack of efficient movement cycles preceded by a reduction in movement amplitude and/or an irregular movement frequency [ 12 – 14 ].…”