Jerker Westin

Automatic and objective assessment of alternating tapping performance in Parkinson’s disease

This paper presents the development and evaluation of a method for enabling quantitative and automatic scoring of alternating tapping performance of patients with Parkinsons disease (PD). Ten healthy elderly subjects and 95 patients in different clinical stages of PD have utilized a touch-pad handheld computer to perform alternate tapping tests in their home environments. First, a neurologist used a web-based system to visually assess impairments in four tapping dimensions (‘speed’, ‘accuracy’, ‘fatigue’ and ‘arrhythmia’) and a global tapping severity (GTS). Second, tapping signals were processed with time series analysis and statistical methods to derive 24 quantitative parameters. Third, principal component analysis was used to reduce the dimensions of these parameters and to obtain scores for the four dimensions. Finally, a logistic regression classifier was trained using a 10-fold stratified cross-validation to map the reduced parameters to the corresponding visually assessed GTS scores. Results showed that the computed scores correlated well to visually assessed scores and were significantly different across Unified Parkinsons Disease Rating Scale scores of upper limb motor performance. In addition, they had good internal consistency, had good ability to discriminate between healthy elderly and patients in different disease stages, had good sensitivity to treatment interventions and could reflect the natural disease progression over time. In conclusion, the automatic method can be useful to objectively assess the tapping performance of PD patients and can be included in telemedicine tools for remote monitoring of tapping.

Motion cue analysis for parkinsonian gait recognition.

This paper presents a computer-vision based marker-free method for gait-impairment detection in Patients with Parkinson’s disease (PWP). The system is based upon the idea that a normal human body attains equilibrium during the gait by aligning the body posture with Axis-of-Gravity (AOG) using feet as the base of support. In contrast, PWP appear to be falling forward as they are less-able to align their body with AOG due to rigid muscular tone. A normal gait exhibits periodic stride-cycles with stride-angle around 45o between the legs, whereas PWP walk with shortened stride-angle with high variability between the stride-cycles. In order to analyze Parkinsonian-gait (PG), subjects were videotaped with several gait-cycles. The subject’s body was segmented using a color-segmentation method to form a silhouette. The silhouette was skeletonized for motion cues extraction. The motion cues analyzed were stride-cycles (based on the cyclic leg motion of skeleton) and posture lean (based on the angle between leaned torso of skeleton and AOG). Cosine similarity between an imaginary perfect gait pattern and the subject gait patterns produced 100% recognition rate of PG for 4 normal-controls and 3 PWP. Results suggested that the method is a promising tool to be used for PG assessment in home-environment.

Validity and Responsiveness of At-Home Touch Screen Assessments in Advanced Parkinson's Disease

The aim of this study was to investigate if a telemetry test battery can be used to measure effects of Parkinsons disease (PD) treatment intervention and disease progression in patients with fluctuations. Sixty-five patients diagnosed with advanced PD were recruited in an open longitudinal 36-month study; 35 treated with levodopa-carbidopa intestinal gel (LCIG) and 30 were candidates for switching from oral PD treatment to LCIG. They utilized a test battery, consisting of self-assessments of symptoms and fine motor tests (tapping and spiral drawings), four times per day in their homes during week-long test periods. The repeated measurements were summarized into an overall test score (OTS) to represent the global condition of the patient during a test period. Clinical assessments included ratings on unified PD rating scale (UPDRS) and 39-item PD questionnaire (PDQ-39) scales. In LCIG-naïve patients, the mean OTS compared to baseline was significantly improved from the first test period on LCIG treatment until month 24. In LCIG-nonnaïve patients, there were no significant changes in the mean OTS until month 36. The OTS correlated adequately with total UPDRS (rho = 0.59) and total PDQ-39 (0.59). Responsiveness measured as effect size was 0.696 and 0.536 for OTS and UPDRS, respectively. The trends of the test scores were similar to the trends of clinical rating scores but the dropout rate was high. Correlations between OTS and clinical rating scales were adequate indicating that the test battery contains important elements of the information of well-established scales. The responsiveness and reproducibility were better for OTS than for total UPDRS.

A web-based system for visualizing upper limb motor performance of Parkinson's disease patients

Objective:To define and evaluate a Computer-Vision (CV) method for scoring Paced Finger-Tapping (PFT) in Parkinsons disease (PD) using quantitative motion analysis of index-fingers and to compare the obtained scores to the UPDRS (Unified Parkinsons Disease Rating Scale) finger-taps (FT).Background:The naked-eye evaluation of PFT in clinical practice results in coarse resolution to determine PD status. Besides, sensor mechanisms for PFT evaluation may cause patients discomfort. In order to avoid cost and effort of applying wearable sensors, a CV system for non-invasive PFT evaluation is introduced.Methods:A database of 221 PFT videos from 6 PD patients was processed. The subjects were instructed to position their hands above their shoulders besides the face and tap the index-finger against the thumb consistently with speed. They were facing towards a pivoted camera during recording. The videos were rated by two clinicians between symptom levels 0-to-3 using UPDRS-FT.The CV method incorporates a motion analyzer and a face detector. The method detects the face of testee in each video-frame. The frame is split into two images from face-rectangle center. Two regions of interest are located in each image to detect index-finger motion of left and right hands respectively. The tracking of opening and closing phases of dominant hand index-finger produces a tapping time-series. This time-series is normalized by the face height. The normalization calibrates the amplitude in tapping signal which is affected by the varying distance between camera and subject (farther the camera, lesser the amplitude). A total of 15 features were classified using K-nearest neighbor (KNN) classifier to characterize the symptoms levels in UPDRS-FT. The target ratings provided by the raters were averaged.Results:A 10-fold cross validation in KNN classified 221 videos between 3 symptom levels with 75% accuracy. An area under the receiver operating characteristic curves of 82.6% supports feasibility of the obtained features to replicate clinical assessments.Conclusions:The system is able to track index-finger motion to estimate tapping symptoms in PD. It has certain advantages compared to other technologies (e.g. magnetic sensors, accelerometers etc.) for PFT evaluation to improve and automate the ratingsObjective: To compare the efficacy of botulinum toxin type A (BTX-A) treatment for patients with primary versus secondary blepharospasm (BS) associated with Parkinson’s disease (PD), with or without deep brain stimulation (DBS). Background: BS, a focal eyelid dystonia, can be idiopathic (primary) or secondary to other disorders such as PD. Furthermore eyelid-opening disorders are common in patients with PD undergoing deep brain stimulation (DBS). BTX-A is the treatment of choice for these conditions. Methods: 27 patients [15 males, age: 65.11 6 13.66 years, disease duration 7.7 6 8.2], newly or routinely treated with BTX-A were recruited including patients with primary BS (N 5 10), secondary BS associated with PD (N 5 6), PD1DBS (N 5 5), and other various types of BS (N 5 6). Patients were evaluated before and 4 weeks following BTX-A injections, using the Blepharospam Disability Scale (BDS), the Blepharospasm Disability Index (BDI), the Jankovic Rating Scale (JRS), the Blepharospasm Movement Scale (BMS), and the Clinical Global Impression of improvement (CGI-I). Additionally all were recorded on a 5-minute videotape and scored by a blinded rater. Results: Following BTX-A injections, our sample as a whole showed a statistically significant improvement in Severity of Illness (2.34 6 1.05 vs. 1.74 6 1.27, p 5 0.013), JRS severity scale (1.96 6 1.22 vs. 1.37 6 1.04, p 5 0.002), BMS severity scale (5.04 6 1.79 vs. 4 6 2.35, p 5 0.04), and the severity rating scale (1.61 6 0.8 vs. 1.19 6 0.84, p 5 0.013). When efficacy was compared by diagnosis group, the best effect was evident in patients with BS secondary to PD and was maximal for the PD patients without DBS who demonstrated significant improvement in Severity of Illness compared to the other two groups. Conclusions: In this study BTX-A was an effective treatment for BS. Patients with PD associated BS showed a better response than those with primary BS.Objective: To develop fMRI-based tools in tremor diagnostics and to demonstrate their clinical applicability. Background: Due to overlapping features of tremor disorders, clinical diagnostic tools are limited. Although seldomly used in diagnostic assessment of tremor, fMRI of pathological brain networks underlying tremor could aid accurate and early diagnosis. fMRI of the closed loop behaviour of the sensorimotor system may manifest itself differently with different tremor disorders and has not been fully explored yet in diagnostics. Methods: Following a literature review that we performed on neuroimaging studies in essential tremor (ET), we developed a novel fMRI setup to investigate pathological brain networks related to tremor. An MR-compatible wrist manipulator, to perturb the sensorimotor loop, is combined with movement measures. Results: Our review showed that current findings are consistent with the hypothesis that the cerebellothalamo-cortical network is involved in ET with a major role for the cerebellum. To date, imaging techniques roughly are divided into structural (n=11) and functional methods (n=24). Limitations include heterogeneity of ET symptoms, spatial resolution and inability to directly relate tremor to functional images. The typical nature of a sensorimotor loop is generally not taken into account. We have developed a high-end novel experimental setup within the MR-environment including artifact-free movement measures (EMG, accelerometry) and a MR-compatible wrist manipulator to apply perturbations. Perturbations applied close to pathological tremor frequencies provide sensory input in passive conditions and manipulate motor action in active conditions. Conclusions: We introduce a multimodal fMRI set-up manipulating the sensorimotor loop to identify faulty brain circuitries. This system can potentially lead to a novel quantitative diagnostic tool for differentiating tremor and other movement disorders.

Self-reported symptoms and motor tests via telemetry in a 36-month levodopa-carbidopa intestinal gel infusion trial

Objective:To define and evaluate a Computer-Vision (CV) method for scoring Paced Finger-Tapping (PFT) in Parkinsons disease (PD) using quantitative motion analysis of index-fingers and to compare the obtained scores to the UPDRS (Unified Parkinsons Disease Rating Scale) finger-taps (FT).Background:The naked-eye evaluation of PFT in clinical practice results in coarse resolution to determine PD status. Besides, sensor mechanisms for PFT evaluation may cause patients discomfort. In order to avoid cost and effort of applying wearable sensors, a CV system for non-invasive PFT evaluation is introduced.Methods:A database of 221 PFT videos from 6 PD patients was processed. The subjects were instructed to position their hands above their shoulders besides the face and tap the index-finger against the thumb consistently with speed. They were facing towards a pivoted camera during recording. The videos were rated by two clinicians between symptom levels 0-to-3 using UPDRS-FT.The CV method incorporates a motion analyzer and a face detector. The method detects the face of testee in each video-frame. The frame is split into two images from face-rectangle center. Two regions of interest are located in each image to detect index-finger motion of left and right hands respectively. The tracking of opening and closing phases of dominant hand index-finger produces a tapping time-series. This time-series is normalized by the face height. The normalization calibrates the amplitude in tapping signal which is affected by the varying distance between camera and subject (farther the camera, lesser the amplitude). A total of 15 features were classified using K-nearest neighbor (KNN) classifier to characterize the symptoms levels in UPDRS-FT. The target ratings provided by the raters were averaged.Results:A 10-fold cross validation in KNN classified 221 videos between 3 symptom levels with 75% accuracy. An area under the receiver operating characteristic curves of 82.6% supports feasibility of the obtained features to replicate clinical assessments.Conclusions:The system is able to track index-finger motion to estimate tapping symptoms in PD. It has certain advantages compared to other technologies (e.g. magnetic sensors, accelerometers etc.) for PFT evaluation to improve and automate the ratingsObjective: To compare the efficacy of botulinum toxin type A (BTX-A) treatment for patients with primary versus secondary blepharospasm (BS) associated with Parkinson’s disease (PD), with or without deep brain stimulation (DBS). Background: BS, a focal eyelid dystonia, can be idiopathic (primary) or secondary to other disorders such as PD. Furthermore eyelid-opening disorders are common in patients with PD undergoing deep brain stimulation (DBS). BTX-A is the treatment of choice for these conditions. Methods: 27 patients [15 males, age: 65.11 6 13.66 years, disease duration 7.7 6 8.2], newly or routinely treated with BTX-A were recruited including patients with primary BS (N 5 10), secondary BS associated with PD (N 5 6), PD1DBS (N 5 5), and other various types of BS (N 5 6). Patients were evaluated before and 4 weeks following BTX-A injections, using the Blepharospam Disability Scale (BDS), the Blepharospasm Disability Index (BDI), the Jankovic Rating Scale (JRS), the Blepharospasm Movement Scale (BMS), and the Clinical Global Impression of improvement (CGI-I). Additionally all were recorded on a 5-minute videotape and scored by a blinded rater. Results: Following BTX-A injections, our sample as a whole showed a statistically significant improvement in Severity of Illness (2.34 6 1.05 vs. 1.74 6 1.27, p 5 0.013), JRS severity scale (1.96 6 1.22 vs. 1.37 6 1.04, p 5 0.002), BMS severity scale (5.04 6 1.79 vs. 4 6 2.35, p 5 0.04), and the severity rating scale (1.61 6 0.8 vs. 1.19 6 0.84, p 5 0.013). When efficacy was compared by diagnosis group, the best effect was evident in patients with BS secondary to PD and was maximal for the PD patients without DBS who demonstrated significant improvement in Severity of Illness compared to the other two groups. Conclusions: In this study BTX-A was an effective treatment for BS. Patients with PD associated BS showed a better response than those with primary BS.Objective: To develop fMRI-based tools in tremor diagnostics and to demonstrate their clinical applicability. Background: Due to overlapping features of tremor disorders, clinical diagnostic tools are limited. Although seldomly used in diagnostic assessment of tremor, fMRI of pathological brain networks underlying tremor could aid accurate and early diagnosis. fMRI of the closed loop behaviour of the sensorimotor system may manifest itself differently with different tremor disorders and has not been fully explored yet in diagnostics. Methods: Following a literature review that we performed on neuroimaging studies in essential tremor (ET), we developed a novel fMRI setup to investigate pathological brain networks related to tremor. An MR-compatible wrist manipulator, to perturb the sensorimotor loop, is combined with movement measures. Results: Our review showed that current findings are consistent with the hypothesis that the cerebellothalamo-cortical network is involved in ET with a major role for the cerebellum. To date, imaging techniques roughly are divided into structural (n=11) and functional methods (n=24). Limitations include heterogeneity of ET symptoms, spatial resolution and inability to directly relate tremor to functional images. The typical nature of a sensorimotor loop is generally not taken into account. We have developed a high-end novel experimental setup within the MR-environment including artifact-free movement measures (EMG, accelerometry) and a MR-compatible wrist manipulator to apply perturbations. Perturbations applied close to pathological tremor frequencies provide sensory input in passive conditions and manipulate motor action in active conditions. Conclusions: We introduce a multimodal fMRI set-up manipulating the sensorimotor loop to identify faulty brain circuitries. This system can potentially lead to a novel quantitative diagnostic tool for differentiating tremor and other movement disorders.

A Treatment-Response Index From Wearable Sensors for Quantifying Parkinson's Disease Motor States

The goal of this study was to develop an algorithm that automatically quantifies motor states (off, on, dyskinesia) in Parkinsons disease (PD), based on accelerometry during a hand pronation-supination test. Clinicians ratings using the Treatment Response Scale (TRS), ranging from −3 (very Off) to 0 (On) to +3 (very dyskinetic), were used as target. For that purpose, 19 participants with advanced PD and 22 healthy persons were recruited in a single center open label clinical trial in Uppsala, Sweden. The trial consisted of single levodopa dose experiments for the people with PD (PwP), where participants were asked to perform standardized wrist rotation tests, using each hand, before and at prespecified time points after the dose. The participants used wrist sensors containing a three-dimensional accelerometer and gyroscope. Features to quantify the level, variation, and asymmetry of the sensor signals, three-level discrete wavelet transform features, and approximate entropy measures were extracted from the sensors data. At the time of the tests, the PwP were video recorded. Three movement disorder specialists rated the participants’ state on the TRS. A Treatment Response Index from Sensors (TRIS) was constructed to quantify the motor states based on the wrist rotation tests. Different machine learning algorithms were evaluated to map the features derived from the sensor data to the ratings provided by the three specialists. Results from cross validation, both in tenfold and a leave-one-individual out setting, showed good predictive power of a support vector machine model and high correlation to the TRS. Values at the end tails of the TRS were under and over predicted due to the lack of observations at those values but the model managed to accurately capture the dose-effect profiles of the patients. In addition, the TRIS had good test–retest reliability on the baseline levels of the PD participants (Intraclass correlation coefficient of 0.83) and reasonable sensitivity to levodopa treatment (0.33 for the TRIS). For a series of test occasions, the proposed algorithms provided dose-effect time profiles for participants with PD, which could be useful during therapy individualization of people suffering from advanced PD.

A method for measuring Parkinson's disease related temporal irregularity in spiral drawings

The objective of this paper was to develop and evaluate clinimetric properties of a method for measuring Parkinsons disease (PD)-related temporal irregularities using digital spiral analysis. In total, 108 (98 patients in different stages of PD and 10 healthy elderly subjects) performed repeated spiral drawing tasks in their home environments using a touch screen device. A score was developed for representing the amount of temporal irregularity during spiral drawing tasks, using Approximate Entropy (ApEn) technique. In addition, two previously published spiral scoring methods were adapted and their scores were analyzed. The mean temporal irregularity score differed significantly between healthy elderly subjects and advanced PD patients (P<;0.005). The ApEn-based method had a better responsiveness and test-retest reliability when compared to the other two methods. In contrast to the other methods, the mean scores of the ApEn-based method improved significantly during a 3 year clinical study, indicating a possible impact of pathological basal ganglia oscillations in temporal control during spiral drawing tasks. In conclusion, the ApEn-based method could be used for differentiating between patients in different stages of PD and healthy subjects. The responsiveness and test-retest reliability were good for the ApEn-based method indicating that this method is useful for measuring upper limb temporal irregularity at a micro-level.

A review of Parkinson’s disease cardinal and dyskinetic motor symptoms assessment methods using sensor systems

This paper is reviewing objective assessments of Parkinson’s disease (PD) motor symptoms, cardinal, and dyskinesia, using sensor systems. It surveys the manifestation of PD symptoms, sensors that were used for their detection, types of signals (measures) as well as their signal processing (data analysis) methods. A summary of this review’s finding is represented in a table including devices (sensors), measures and methods that were used in each reviewed motor symptom assessment study. In the gathered studies among sensors, accelerometers and touch screen devices are the most widely used to detect PD symptoms and among symptoms, bradykinesia and tremor were found to be mostly evaluated. In general, machine learning methods are potentially promising for this. PD is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Combining existing technologies to develop new sensor platforms may assist in assessing the overall symptom profile more accurately to develop useful tools towards supporting better treatment process.

Combined fine-motor tests and self-assessments for remote detection of motor fluctuations

A major problem with the clinical management of fluctuating movement disorders, e.g. Parkinsons disease (PD), is the large variability in manifestation of symptoms among patients. In this conditio ...

Methods for Detection of Speech Impairment Using Mobile Devices

Speech impairment is an important symptom of Parkinson’s disease (PD). This paper presents a detailed systematic literature review on speech impairment assessment through mobile devices. A two-tier ...