Multiple system atrophy (MSA) affects the hypothalamus, similar to other neurological diseases. 1 Hypothalamic cells synthesize antidiuretic hormone (ADH), which increases water reuptake in the kidney. Hypothalamic disturbances can lead to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and resultant hyponatremia. ADH levels usually increase in SIADH. However, normal ADH levels are occasionally seen, but they are inappropriate in the presence of abnormally decreased osmolarity (<280 mOsm/kg), a condition thought to suppress physiological ADH secretion. 2 To date, 6 patients with MSA had SIADH (Table 1). 3 We describe the first MSA patient with extreme hyponatremia (99 mEq/L) and the highest reported ADH concentration. We also measured ADH in 14 severely disabled patients with MSA, but not symptomatic SIADH.
Functional movement disorders (FMD) are characterized by motor symptoms (e.g., tremor, gait disorder, and dystonia) that are not compatible with movement abnormalities related to a known organic cause. One key clinical feature of FMD is that motor symptoms are similar to voluntary movements but are subjectively experienced as involuntary by patients. This gap might be related to abnormal self-recognition of bodily action, which involves two main components: sense of agency and sense of body ownership. The aim of this study was to systematically investigate whether this function is altered in FMD, specifically focusing on the subjective feeling of agency, body ownership, and their interaction during normal voluntary movements. Patients with FMD (n = 21) and healthy controls (n = 21) underwent the moving Rubber Hand Illusion (mRHI), in which passive and active movements can differentially elicit agency, ownership or both. Explicit measures of agency and ownership were obtained via a questionnaire. Patients and controls showed a similar pattern of response: when the rubber hand was in a plausible posture, active movements elicited strong agency and ownership; implausible posture of the rubber hand abolished ownership but not agency; passive movements suppressed agency but not ownership. These findings suggest that explicit sense of agency and body ownership are preserved in FMD. The latter finding is shared by a previous study in FMD using a static version of the RHI, whereas the former appears to contrast with studies demonstrating altered implicit measures of agency (e.g., sensory attenuation). Our study extends previous findings by suggesting that in FMD: (i) the sense of body ownership is retained also when interacting with the motor system; (ii) the subjective experience of agency for voluntary tapping movements, as measured by means of mRHI, is preserved.
BACKGROUND: Rehabilitation has proven effective in improving motor symptoms (i.e., weakness, tremor, gait and balance disorders) in patients with Functional Motor Disorders (FMDs). Its effects on non-motor symptoms (NMSs) such as fatigue, pain, depression, anxiety and alexithymia, have not been explored yet. OBJECTIVE: To explore the effects of a validated inpatient 5-day rehabilitation program, followed by a home-based self-management plan on functional motor symptoms, NMSs, self-rated perception of change, and quality of life (QoL). METHODS: 33 FMD patients were enrolled. Measures for motor symptoms and NMSs were primary outcomes. Secondary outcomes included measures of self-perception of change and QoL. Patients were evaluated pre-treatment (T0), post-treatment (T1), and 3-month follow-up (T2). RESULTS: There was an overall significant decrease in functional motor symptoms, general, physical, and reduced-activity fatigue (for all, p < 0.001). Post hoc comparison showed significant improvements at T1, whereas effects remained significant at T2 for motor symptoms and physical fatigue. Gait and balance, alexithymia, and physical functioning (QoL) significantly improved at T2. More than 50% of patients reported marked improvement at T1 and T2. CONCLUSIONS: Our study suggests the benefits of rehabilitation and self-management plan on functional motor symptoms and physical fatigue in the medium-term. More actions are needed for the management of pain and other distressing NMSs in FMDs.
In healthy people, energy expenditure is generally higher during walking with poles (WP) than during conventional walking (W). In persons with Parkinson's disease (PD), walking is slower and may be associated with greater energy consumption, stride-to-stride variability, and difficulty in regulating stride length. The aim of this study was to determine whether treadmill WP at three different speeds could induce changes in gait kinematics and oxygen consumption in PD patients. The study sample was 20 patients with mild-to-moderate PD and 20 age-matched healthy controls. Subjects underwent 5-min W and WP treadmill tests at three different speeds (2.5, 3.5, and 4.5 km/h). Metabolic and gait parameters (ventilation, gas exchange, stride count and length) were recorded. As compared with the healthy controls, higher energy consumption (P < 0.05) (and other metabolic parameters), shorter stride, and reduced cadence (P < 0.05) were observed for the PD patients, independent of the walking technique. All subjects were noted to take longer strides during WP (P < 0.001), especially at the lowest treadmill speed. However, significantly higher energy consumption was observed only for the healthy controls (P < 0.05). No changes in metabolic parameters during WP were recorded; however, a substantial improvement in gait cycle length was noted for the PD patients.
Aim: Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized, among the others, by muscle weakness. PD patients reach lower values of peak torque during maximal voluntary contractions but also slower rates of torque development (RTD) during explosive contractions. The aim of this study was to better understand how an impairment in structural/mechanical (peripheral) factors could explain the difficulty of PD patients to raise torque rapidly. Methods: Participants (PD patients and healthy matched controls) performed maximum voluntary explosive fixed-end contraction of the knee extensor muscles during which dynamic muscle shape changes (in muscle thickness, pennation angle, and belly gearing: the ratio between muscle belly velocity and fascicle velocity), muscle-tendon unit (MTU) stiffness and EMG activity of the vastus lateralis (VL) were investigated. Both the affected (PDA) and less affected limb (PDNA) were investigated in patients.Results: Control participants reached higher values of peak torque and showed a better capacity to express force rapidly compared to patients (PDA and PDNA). EMG activity was observed to differ between patients (PDA) and controls, but not between controls and PDNA. This suggests a specific neural/nervous effect on the most affected side. On the contrary, MTU stiffness and dynamic muscle shape changes were found to differ between controls and patients, but not between PDA and PDNA. Both sides are thus similarly affected by the pathology.
Conclusion:The higher MTU stiffness in PD patients is likely responsible for the impaired muscle capability to change in shape which, in turn, negatively affects the torque rise.
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