A gait-based paradigm to investigate central body representation in cervical dystonia patients

BACKGROUND

Cervical dystonia (CD) is a common adult-onset idiopathic form of dystonia characterized by an abnormal head posture caused by an excessive activity of the neck muscles. The position of the head is important to direct viewpoint in the rounding environment, and the body orientation, during gait, must be coherent with the subjective straight ahead (SSA). An alteration of the SSA, as in the case of CD patients, could affect gait when visual input is not available. The aim of this study was to probe the behavior of patients with CD during blindfolded walking, investigating the ability to walk straight ahead based only on somatosensory and vestibular information.

METHODS

In this observational cross-sectional study, patients with CD and healthy control subjects (HC) were compared. All participants were evaluated through a gait analysis during blindfolded walking on a GAITRite carpet, relying on their own sense of straightness.

RESULTS

Patients with CD showed lower values of path length (p < 0.001), a lower number of steps on the carpet (p < 0.001). A higher number of CD patients deviated during the task, walking out of the carpet, (p < 0.005) compared to HS. No relation was found between the dystonic side and the gait trajectory deviation. A significant correlation was found between pain symptom and gait performance.

CONCLUSIONS

CD patients showed dysfunctions in controlling dynamic body location during walking without visual afferences, while the dystonic side does not seem to be related to the lateral deviation of the trajectory. Our results would assume that a general proprioceptive impairment could lead to an improper body position awareness in patients with CD.

Correlation between Quality of Life and severity of Parkinson's Disease by assessing an optimal cut-off point on the Parkinson's Disease questionnaire (PDQ-39) as related to the Hoehn & Yahr (H&Y) scale

PURPOSE

Strong evidence shows that symptoms in individuals with Parkinson's Disease (PD) restrict both their independence and social participation, leading to a low Quality of Life (QoL). Conversely, a reduced QoL has a negative impact on symptoms. The aim is to evaluate the correlation between QoL and severity of PD by assessing the presence of an optimal cut-off point on the Parkinson's disease questionnaire (PDQ-39) as related to the Hoehn &Yahr (H&Y) scale in a cohort of Italian adults with PD.

METHODS

A multicenter, cross-sectional study was performed. This study was conducted on a cohort of consecutive individuals. All participants were evaluated with the PDQ-39, and the severity of PD was recorded according to the H&Y scale by a neurologist. Receiver op-erating characteristic (ROC) curves and coordinates, visually inspected, were used to find cut-off points with optimal sensitivity and specificity. These were in turn used to determine the optimal PDQ-39 cut-off score for identifying disease severity according to H&Y stages.

RESULTS

513 individuals were included in the study. The ROC curve analysis showed that QoL worsened with an increase in disease severity and age. Moreover, QoL was worse in females.

CONCLUSIONS

The results of this study allowed for the correlation of QoL and disease severity in a cohort of individuals with PD. With this cut-off point, it is now possible to make a determination of QoL of an individual with PD at a certain stage of the disease, in a specific age range, and of a particular gender.

Psychometric properties of the Italian version of the Barthel Index in patients with Parkinson's disease: a reliability and validity study

The Barthel Index (BI) is used in Italy to measure the severity of disability and to identify patients suitable for admission to rehabilitation units. The objective of this psychometric study was to validate the Italian version of the BI in a population of patients with Parkinson's disease (PD). The study was conducted at three neurological and rehabilitation centres in Rome, Italy. The BI was administered to outpatients with PD. The reliability of the scale was assessed using Cronbach's alpha for internal consistency; the intra-class correlation coefficient (ICC) was used to measure its intra- and inter-rater reliability. Pearson's correlation coefficient was calculated to evaluate its validity, comparing it with the Parkinson's disease Questionnaire (PDQ-39), the Italian version of the Geriatric Depression Scale (GDS), the Hospital Anxiety and Depression Scale (HADS), and the Short Form 36-Health Survey Questionnaire (SF-36). The BI was administered to 94 patients with PD. The psychometric properties measured were significant: Cronbach's alpha was 0.866 and the ICC for intra- and inter-rater reliability was 0.998 and 0.993, respectively. Pearson's correlation coefficient showed good correlation with the PDQ-39, GDS, HADS and SF-36 (p < 0.01). The BI is a valid and reliable tool for measuring disability in a PD population.

Abnormal lateralization of fine motor actions in Tourette syndrome persists into adulthood

Youth with Tourette syndrome (TS) exhibit, compared to healthy, abnormal ability to lateralize digital sequential tasks. It is unknown whether this trait is related to inter-hemispheric connections, and whether it is preserved or lost in patients with TS persisting through adult life. We studied 13 adult TS patients and 15 age-matched healthy volunteers. All participants undertook: 1) a finger opposition task, performed with the right hand (RH) only or with both hands, using a sensor-engineered glove in synchrony with a metronome at 2 Hz; we calculated a lateralization index [(single RH-bimanual RH)/single RH X 100) for percentage of correct movements (%CORR); 2) MRI-based diffusion tensor imaging and probabilistic tractography of inter-hemispheric corpus callosum (CC) connections between supplementary motor areas (SMA) and primary motor cortices (M1). We confirmed a significant increase in the %CORR in RH in the bimanual vs. single task in TS patients (p<0.001), coupled to an abnormal ability to lateralize finger movements (significantly lower lateralization index for %CORR in TS patients, p = 0.04). The %CORR lateralization index correlated positively with tic severity measured with the Yale Global Tic Severity Scale (R = 0.55;p = 0.04). We detected a significantly higher fractional anisotropy (FA) in both the M1-M1 (p = 0.036) and the SMA-SMA (p = 0.018) callosal fibre tracts in TS patients. In healthy subjects, the %CORR lateralization index correlated positively with fractional anisotropy of SMA-SMA fibre tracts (R = 0.63, p = 0.02); this correlation was not significant in TS patients. TS patients exhibited an abnormal ability to lateralize finger movements in sequential tasks, which increased in accuracy when the task was performed bimanually. This abnormality persists throughout different age periods and appears dissociated from the transcallosal connectivity of motor cortical regions. The altered interhemispheric transfer of motor abilities in TS may be the result of compensatory processes linked to self-regulation of motor control.

Evaluation of physical therapy in parkinsonian patients with freezing of gait: a pilot study

Objective: Freezing of gait is a frequently disabling symptom in Parkinson's disease, poorly responding to dopaminergic treatment. We investigated the short-term effectiveness of a rehabilitation protocol in parkinsonian patients with freezing of gait.

Design: Prospective, uncontrolled pilot study with open label design.

Setting: Outpatient service for rehabilitation of neurological disorders.

Subjects: Twelve patients (8 male, 4 female; aged 59-78 years; Hoehn-Yahr stage: 2-3; mean disease duration: 14.29±SD 4.1 years).

Interventions: Patients attended three (45 min) sessions every week, over a six-week period, of physical therapy focused to improve balance, postural control and walking, and to learn new strategies for overcoming freezing of gait.

Main outcome measures: Patients were evaluated before (T0), at the end (T1), and one month after (T2) rehabilitation by means of clinical rating scales (Unified Parkinson Disease Rating Scale-Motor Section; Freezing of Gait Questionnaire; Parkinson Disease Quality of Life Score) and gait parameters (number of strides, stride length and velocity) during a standardized walking test.

Results: The scores of Freezing of Gait Questionnaire and of Parkinson Disease Quality of Life Questionnaire (but not of the Unified Parkinson Disease Rating Scale-Motor Section) were significantly improved after treatment (T1). Gait parameters were significantly improved at T1 and T2.

Conclusions: We showed the potential short-term efficacy of a rehabilitative approach to freezing of gait in Parkinson's disease. The positive outcome was documented by clinical rating scales and objective gait evaluation. The rapid reversibility of the clinical benefit suggests that further studies are needed to better define the optimal frequency and duration of treatment.

Interaction between vision and neck proprioception in the control of stance

Balance control depends on the interaction of multiple inputs originating from different sensory systems. Here, we investigated the effect on quiet human stance of changing the visual condition prior to a proprioceptive perturbation produced by vibration of dorsal neck muscles. In complete absence of visual references, the amplitude of the postural responses to neck vibration (forward shift of the centre of foot pressure) was the largest and became progressively larger as a function of the repetition of administered stimuli. The posture-destabilizing effect of vibration eyes-closed (EC) and the build-up effect were reduced if vibration was preceded by a period during which vision was allowed (EO). Similarly, the small destabilizing effect of vibration EO was increased if vibration was preceded by an EC period. The fore-period must last more than 3 s in order to affect the response to neck muscle vibration. The responsiveness to a proprioceptive disturbing input does not immediately change on adding or subtracting vision, but a finite time period must elapse before the postural "set" defined by vision is fully established. The findings underline the importance of time when vision is used in re-weighting the excitability of the postural control mechanisms.