Wearable Electronics Assess the Effectiveness of Transcranial Direct Current Stimulation on Balance and Gait in Parkinson's Disease Patients

Currently, clinical evaluation represents the primary outcome measure in Parkinson's disease (PD). However, clinical evaluation may underscore some subtle motor impairments, hidden from the visual inspection of examiners. Technology-based objective measures are more frequently utilized to assess motor performance and objectively measure motor dysfunction. Gait and balance impairments, frequent complications in later disease stages, are poorly responsive to classic dopamine-replacement therapy. Although recent findings suggest that transcranial direct current stimulation (tDCS) can have a role in improving motor skills, there is scarce evidence for this, especially considering the difficulty to objectively assess motor function. Therefore, we used wearable electronics to measure motor abilities, and further evaluated the gait and balance features of 10 PD patients, before and (three days and one month) after the tDCS. To assess patients' abilities, we adopted six motor tasks, obtaining 72 meaningful motor features. According to the obtained results, wearable electronics demonstrated to be a valuable tool to measure the treatment response. Meanwhile the improvements from tDCS on gait and balance abilities of PD patients demonstrated to be generally partial and selective.

The effect of cell phone use on postural balance and mobility in older compared to young adults

Cell phone use is considered as an essential part of everyday life saturating all age groups and demographics. This study aimed to explore the effect of various cell phone functions on postural control and mobility in the elderly. Twenty healthy older (mean age 72.5±2.9) and twenty young (26.3±2.8) adults participated in this study. Postural balance was assessed by measuring the center of pressure (CoP) displacement with (talking on a cell phone (CONVERSE), dialing a number (DIAL) and listening to music (MUSIC)) and without cell phone use. Mobility was assessed by the Timed Up and Go Test (TUGT). Results showed that for both groups, the CoP parameters increased significantly during the CONVERSE (p<0.001) and the DIAL (CoP_area, CoP_X: p<0.05; CoP_Y: p<0.01) conditions compared to the control condition. Moreover, the CoP_area values were significantly higher during the CONVERSE condition in comparison to the DIAL (p<0.05) one. In older adults, the TUGT scores increased significantly in the DIAL (p<0.01) condition compared to the CONVERSE and the MUSIC conditions. In conclusion, cell phone use impairs similarly standing postural balance of elderly and young adults. Interestingly, in the elderly, all cell phone functions used altered mobility with the dialing function causing the largest mobility deterioration.

Does radiation dose to the vestibule predict change in balance function and patient perceived dizziness following stereotactic radiotherapy for vestibular schwannoma?

OBJECTIVE

To date, the majority of the vestibular schwannoma (VS) literature has focused on tumor control rates, facial nerve function and hearing preservation. Other factors that have been shown to significantly affect quality-of-life (QOL), such as dizziness, remain understudied. The primary objective of the current study is to investigate the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported dizziness handicap.

MATERIALS AND METHODS

This is a prospective observational pilot study at a tertiary academic referral center including all subjects that underwent linear accelerator-based stereotactic radiotherapy (SRS) for sporadic VS and completed pre-treatment and post-treatment vestibular testing and Dizziness Handicap Inventory (DHI) questionnaires. Associations between objective vestibular test results, patient-reported DHI scores and radiation dose parameters were investigated.

RESULTS

Ten patients met inclusion criteria. Tumor control was achieved in all individuals. There were no statistically significant associations or identifiable trends between radiation dose and change in vestibular function or DHI scores. Notably, the four ears receiving the highest vestibular dose had minimal changes in vestibular function tests and DHI scores.

CONCLUSIONS

To the best of our knowledge, no previous reports have described the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported DHI. Based on these preliminary data, radiation dose to the vestibule does not reliably predict change in objective or subjective vestibular outcome measures.

Human body area factors for radiation exchange analysis: standing and walking postures

Effective radiation area factors (f (eff)) and projected area factors (f (p)) of unclothed Caucasians' standing and walking postures used in estimating human radiation exchange with the surrounding environment were determined from a sample of adults in Canada. Several three-dimensional (3D) computer body models were created for standing and walking postures. Only small differences in f (eff) and f (p) values for standing posture were found between gender (male or female) and body type (normal- or over-weight). Differences between this study and previous studies were much larger: ≤0.173 in f (p) and ≤0.101 in f (eff). Directionless f (p) values for walking posture also had only minor differences between genders and positions in a stride. However, the differences of mean directional f (p) values of the positions dependent on azimuth angles were large enough, ≤0.072, to create important differences in modeled radiation receipt. Differences in f (eff) values were small: 0.02 between the normal-weight male and female models and up to 0.033 between positions in a stride. Variations of directional f (p) values depending on solar altitudes for walking posture were narrower than those for standing posture. When both standing and walking postures are considered, the mean f (eff) value, 0.836, of standing (0.826) and walking (0.846) could be used. However, f (p) values should be selected carefully because differences between directional and directionless f (p) values were large enough that they could influence the estimated level of human thermal sensation.

Static magnetic field-induced anti-nociceptive effect and the involvement of capsaicin-sensitive sensory nerves in this mechanism

Data concerning the effect of static magnetic field (SMF) on nociceptive processes are contradictory in the literature probably due to differences in species, characteristics of the magnetic fields, and duration of the exposure. The aim of the present series of experiments was to elucidate the action of acute full-body exposure of mice to a special SMF developed and validated by us on acute visceral and somatic chemonociception and inflammatory mechanical hyperalgesia. SMF exposure significantly diminished the number of acetic acid- or MgSO4-induced abdominal contractions (acute visceral nociception), formalin-evoked paw lickings and liftings in both phase I (acute somatic nociception) and phase II (acute inflammatory nociception) and mechanical hyperalgesia evoked by i.pl. injection of carrageenan as well as the TRPV1 capsaicin receptor agonist resiniferatoxin. Selective inactivation of capsaicin-sensitive sensory fibres by high dose resiniferatoxin pretreatment decreased nocifensive behaviours in phase II of the formalin test to a similar extent suggesting that pro-inflammatory neuropeptides such as substance P and calcitonin gene-related peptide released from these fibres are involved in this inflammatory reaction. Significant inhibitory effects of SMF on formalin-induced nociception and carrageenan-evoked hyperalgesia were absent in resiniferatoxin-pretreated mice, which also points out that capsaicin-sensitive nerves are involved in the SMF-induced anti-nociceptive action.

Impact of surgery and adjuvant therapy on balance function in children and adolescents with cerebellar tumors

OBJECTIVES

This study examined the effects of posterior fossa tumor surgery and concomitant irradiation and/or chemotherapy on the long-term recovery of balance function in children and adolescent patients.

SUBJECTS AND METHODS

22 patients, treated during childhood for a benign (n = 14) or malignant cerebellar tumor (n = 8), were examined in chronic state (mean latency between surgery and testing: 7.7 years, range 3 - 17 years). Postural impairments were assessed with static and dynamic posturography. All cerebellar lesions were documented by standardized and normalized MRI data. Healthy age- and gender-matched subjects served as a control group.

RESULTS

Comparing the balance function of (i) children with or without affected cerebellar nuclei and (ii) children with and without adjuvant chemotherapy and/or radiotherapy revealed that damage to the cerebellar nuclei had more impact on neurological impairment than concomitant tumor therapy. Balance abnormalities were most pronounced when a lesion affected the fastigial nucleus. Chemotherapy with its neurological side effect was associated with enhanced postural sway in only two children with malignant tumors.

CONCLUSIONS

The study results indicate that the sparing of the deep cerebellar nuclei had the greatest impact on the recovery of balance function in pediatric patients treated for both a benign or malignant cerebellar tumor.

Impact of subthalamic nucleus stimulation on the initiation of gait in Parkinson’s disease

The effects of subthalamic nucleus (STN) stimulation on the anticipatory postural actions associated with the initiation of gait were studied in ten patients with idiopathic Parkinson's disease undergoing therapeutic deep brain stimulation. Kinematic, dynamic and electromyographic analysis was performed before and while subjects were starting gait in response to an external cue. Effects of STN stimulation on the standing posture preceding the go signal included significant improvement of the vertical alignment of the trunk and shank, decrease of the hip joint moment, backward shift of the center of pressure (CoP) and reduction of abnormal tonic and/or rhythmic activity in the thigh and leg muscles. Responses to bilateral STN stimulation were more consistent than those evoked by unilateral stimulation. Moreover, comparison between postural changes induced by STN stimulation applied prior to the gait initiation cue and during simple quiet standing revealed more significant responses in the former condition. Effects on the actual gait initiation process included shortening of the imbalance phase, larger backward/lateral displacement of CoP and more physiological expression of the underlying anticipatory muscular synergy. Additional changes were shortening of the unloading phase, shortening of the first-swing phase and increase in the length of the first step. Results demonstrate substantial influence of STN stimulation on functionally basic motor control mechanisms. In particular, the evidence of more significant responses upon attention-demanding conditions and the remarkable effects on postural programmes sub-serving feed-forward regulation of the onset of complex multijoint movements, suggests a consistent action on postural sub-systems relying on cognitive data processing and internal models of body mechanics.

Circling, deafness, and yellow coat displayed by yellow submarine (ysb) and light coat and circling (lcc) mice with mutations on chromosome 3

We describe here two mouse mutants, yellow submarine (Ysb) and light coat and circling (Lcc). Ysb arose as the result of insertions of a transgene, pAA2, into the genome. Lcc is an independent, radiation-induced mutation. Both mutants are characterized by recessive circling behavior and deafness, associated with a non-segregating, semi-dominant yellow coat color. Complementation tests showed that Ysb and Lcc are allelic. We attribute the yellow coat in Ysb and Lcc mice to the absence of black awl overhairs, increased agouti zigzag underhairs, and the presence of agouti awls with long subapical yellow pigment. Chromosomal mapping and genomic characterization showed the Ysb and Lcc mutations involve complex chromosomal rearrangements in overlapping regions of mouse chromosome 3, A2/A3-B/C and B-E1, respectively. Ysb and Lcc show for the first time, to our knowledge, the presence of genes in the B-C region of chromosome 3 important for balance and hearing and the pigmentation and specification of coat hair.

A comparison of rheumatoid arthritis and fibromyalgia patients and healthy controls exposed to a pulsed (200 microT) magnetic field: effects on normal standing balance

Specific weak time varying pulsed magnetic fields (MF) have been shown to alter animal and human behaviors, including pain perception and postural sway. Here we demonstrate an objective assessment of exposure to pulsed MF's on Rheumatoid Arthritis (RA) and Fibromyalgia (FM) patients and healthy controls using standing balance. 15 RA and 15 FM patients were recruited from a university hospital outpatient Rheumatology Clinic and 15 healthy controls from university students and personnel. Each subject stood on the center of a 3-D forceplate to record postural sway within three square orthogonal coil pairs (2 m, 1.75 m, 1.5 m) which generated a spatially uniform MF centered at head level. Four 2-min exposure conditions (eyes open/eyes closed, sham/MF) were applied in a random order. With eyes open and during sham exposure, FM patients and controls appeared to have similar standing balance, with RA patients worse. With eyes closed, postural sway worsened for all three groups, but more for RA and FM patients than controls. The Romberg Quotient (eyes closed/eyes open) was highest among FM patients. Mixed design analysis of variance on the center of pressure (COP) movements showed a significant interaction of eyes open/closed and sham/MF conditions [F=8.78(1,42), P<0.006]. Romberg Quotients of COP movements improved significantly with MF exposure [F=9.5(1,42), P<0.005] and COP path length showed an interaction approaching significance with clinical diagnosis [F=3.2(1,28), P<0.09]. Therefore RA and FM patients, and healthy controls, have significantly different postural sway in response to a specific pulsed MF.

Human standing balance is affected by exposure to pulsed ELF magnetic fields: light intensity-dependent effects

There is evidence in animals that behavioral and physiological responses to static and extremely low frequency magnetic fields (ELFMF) is affected by the presence of light during magnetic field exposures. Here we report that the effect of a specific pulsed ELFMF (PEMF) on human standing balance is modulated by light intensity during exposure. Under a low light condition (0.12 W/m2), nine healthy human volunteers stood on a 3D forceplate, throughout four 2 min exposures (eyes open/eyes close, sham/PEMF of 200 +/- 1 microTpk, order randomized). There was a significant increase in standing movement during PEMF exposure during eyes closed. In a second experiment on 26 normal subjects exposed to the identical protocol, but at greater light intensities (0.51 W/m2), a significant but opposite effect was observed.

Effect of cerebellar granule cell depletion on learning of the equilibrium behaviour: study in postnatally X-irradiated rats

To assess the role of the mossy fibre-granule cell pathway in learning, the cerebellum of young DA/HAN strain rats was irradiated to make the cortex completely or partially agranular. The X-rays were delivered according to two different schedules, between 5-14 postnatal days (early group) and between 10-14 postnatal days (late group). Histological controls at 35 days showed a mean loss of granule cells of 96 +/- 1% in the early group and of 61 +/- 3% in the late group. The irradiated animals were subjected, from day 23 to day 35, to daily sensorimotor training on a rotorod. The scores and the strategy used (walking or hanging) by the rats were noted. The results demonstrate that a partial loss of granule cells due to a late X-irradiation schedule induced mild motor disabilities but no learning deficit, the only problem being difficulty in elaborating rapidly an efficient strategy to solve a novel problem. A sub-total loss of the granule cells, due to an early X-irradiation schedule, induced gross motor disabilities and the animals used hanging > 90% of the time. Due to the discrepancy between the learning abilities, which were preserved at least in part, and the gross motor impairments, the animals elaborated a novel strategy (jumping from the beam), allowing them to escape the experimental situation. This avoidance behaviour may be due to a decrease of anxiety, a lack of behavioural inhibition and/or attentional deficits that have been already observed in several other examples of cerebellar abnormalities.

[Physiological characteristics of posture maintenance by dogs during immediate reaction to irradiation]

The ability of dogs to maintain a vertical posture during the first hours after irradiation at a dose of 10 or 80 Gy was investigated. Two experiments were performed. In the first experiment, during 5 hours after irradiation the vector stabilogram area, peak muscle efforts and sensorimotor coordination were measured 10 times every 30 min. In the second experiment, postural responses to perturbations were measured before and after irradiation at a dose of 10 Gy. During exposure to 10 Gy maximum values of the vector stabilogram area reflected initial excitation and motor unrest, that preceded vomiting, while minimum values of the parameter were related to hypodynamia during 3-5 hours after exposure. During exposure to 80 Gy minimum values of the vector stabilogram area reflected the hypodynamic phase while maximum values were related to the phase of distinct cerebral lesions. A reliable indicator of the quality of vertical posture maintenance, that correlates with the post-irradiation quality of purposeful actions, including intermittent physical acts, or actions, requiring highly precise coordination, is the rate of posture recovery after instantaneous platform displacement. This parameter declined after irradiation, the maximum decrease being during the 4-5th hour.

Dorsal light response and changes of its responses under varying acceleration conditions

In order to improve our understanding about functions of the gravity sensors, we have conducted four experiments in goldfish: 1) To define the effect of visual information influx on the static labyrinthine response, the dorsal light response (DLR) which had been proposed by von Holst as a model for postural adjustment in fish was reexamined with a newly designed, rotatory illumination device. The fish responded to illumination from the upper half of the visual field and a narrow range around 180 degrees of the lower half visual field. The maximal tilting angle of normal fish was about 40 degrees under horizontal illumination. 2) Under the changes of the gravito-inertial force level produced by a linear sled, the threshold of the gravity sensors was determined from postural adjustment responses. 3) Under hypogravic conditions during the parabolic flight of an airplane, the light-dependent behavior was investigated in intact and labyrinthectomized goldfish. 4) As one of the most likely candidates of the neural centers for the DLR, the valvula cerebelli, which receives its visual information not through the optic tectum but through the pretectal areas, is confirmed by the brain lesion experiments.

Uranium and thorium isotopes and their state of equilibria in lungs from uranium miners

Radiochemical analysis of seven lungs obtained at autopsy show that concentrations ranged between 6 and 63 pCi/kg for 238U and 6-66 pCi/kg, for 234U. Similarly, 230Th ranged from 17 to 54 pCi/kg, two orders of magnitude higher than 230Th observed in the lungs of the general population from the Western mining region. For individual lungs, 238U and 234U were close to equilibrium with an average ratio of 238U/234U of 0.94 and a range of 0.80-1.02. Surprisingly, 230Th was close to equilibrium with 234U with a 230Th/234U ratio of 1.1 and a range from 0.54 to 2.6. Equilibrium between U and Th isotopes is in contrast to the disequilibrium reported in beagles which chronically inhaled carnotite, where the 230Th/234U ratio was observed to range from 5.4 to 7.4 with an average of 6.3. The average radiation dose rate to lung from each of the three radionuclides was calculated as follows: D = 18.7 CE where D = dose rate in mrad/year, C = activity concentration in tissue in pCi/g and E = energy absorbed per disintegration in MeV. The combined radiation dose rate (at death) due to three long-lived radionuclides 238U, 234U and 230Th varied from 2.5 to 14.2 mrad/yr with a mean of 9.6 mrad/yr. The concentration of 226Ra and daughters in the lung was not determined. An upper limit to the dose rate from the whole chain, calculated assuming 226Ra through 210Po are in equilibrium with 238U, 234U and 230Th, would be 30 mrad/yr.

The influence of ultrasound and temperature on the cochlear microphonic response following a round window irradiation

Impairment of cochlear function was investigated following ultrasonic irradiation of the vestibule and the cochlea through the round window in cats and guinea pigs. Selective destruction of the vestibular balance mechanism with negligible impairment of cochlear microphonic response was achieved, provided that the ultrasound beam was directed away from the cochlea and towards the ampulla of the superior semicircular canal. Directing ultrasound into the cochlea produced a depression in C.M. which was greatest in the higher frequency responsive area corresponding to the region of the first two cochlear turns. The degree of cochlear microphonic depression increased as the duration of irradiation was extended. The occurrence of a significant temperature increase accompanying the application of ultrasound implicated the involvement of a thermal mechanism in addition to the mechanical disruptive effect of ultrasound.