Targeted tDCS Mitigates Dual-Task Costs to Gait and Balance in Older Adults.

OBJECTIVE: Among older adults, the ability to stand or walk while performing cognitive tasks (ie, dual-tasking) requires coordinated activation of several brain networks. In this multicenter, double-blinded, randomized, and sham-controlled study, we examined the effects of modulating the excitability of the left dorsolateral prefrontal cortex (L-DLPFC) and the primary sensorimotor cortex (SM1) on dual-task performance "costs" to standing and walking. METHODS: Fifty-seven older adults without overt illness or disease completed 4 separate study visits during which they received 20 minutes of transcranial direct current stimulation (tDCS) optimized to facilitate the excitability of the L-DLPFC and SM1 simultaneously, or each region separately, or neither region (sham). Before and immediately after stimulation, participants completed a dual-task paradigm in which they were asked to stand and walk with and without concurrent performance of a serial-subtraction task. RESULTS: tDCS simultaneously targeting the L-DLPFC and SM1, as well as tDCS targeting the L-DLPFC alone, mitigated dual-task costs to standing and walking to a greater extent than tDCS targeting SM1 alone or sham (p < 0.02). Blinding efficacy was excellent and participant subjective belief in the type of stimulation received (real or sham) did not contribute to the observed functional benefits of tDCS. INTERPRETATION: These results demonstrate that in older adults, dual-task decrements may be amenable to change and implicate L-DPFC excitability as a modifiable component of the control system that enables dual-task standing and walking. tDCS may be used to improve resilience and the ability of older results to walk and stand under challenging conditions, potentially enhancing everyday functioning and reducing fall risks. ANN NEUROL 2021;90:428-439.

Combining transcranial direct current stimulation with a motor-cognitive task: the impact on dual-task walking costs in older adults.

BACKGROUND: The performance of a secondary task while walking increases motor-cognitive interference and exacerbates fall risk in older adults. Previous studies have demonstrated that transcranial direct current stimulation (tDCS) may improve certain types of dual-task performance, and, that tDCS delivered during the performance of a task may augment the benefits of stimulation, potentially reducing motor-cognitive interference. However, it is not yet known if combining multi-target tDCS with the simultaneous performance of a task related to the tDCS targets reduces or increases dual-task walking costs among older adults. The objectives of the present work were (1) To examine whether tDCS applied during the performance of a task that putatively utilizes the brain networks targeted by the neuro-stimulation reduces dual-task costs, and (2) to compare the immediate after-effects of tDCS applied during walking, during seated-rest, and during sham stimulation while walking, on dual-task walking costs in older adults. We also explored the impact on postural sway and other measures of cognitive function. METHODS: A double-blind, 'within-subject' cross-over pilot study evaluated the effects of 20 min of anodal tDCS targeting both the primary motor cortex (M1) and the left dorsolateral prefrontal cortex (lDLPFC) in 25 healthy older adults (73.9 ± 5.2 years). Three stimulation conditions were assessed in three separate sessions: (1) tDCS while walking in a complex environment (tDCS + walking), (2) tDCS while seated (tDCS + seated), and (3) walking in a complex environment with sham tDCS (sham + walking). The complex walking condition utilized virtual reality to tax motor and cognitive abilities. During each session, usual-walking, dual-task walking, quiet standing sway, and cognitive function (e.g., Stroop test) were assessed before and immediately after stimulation. Dual-task costs to gait speed and other measures were computed. RESULTS: The dual-task cost to gait speed was reduced after tDCS + walking (p = 0.004) as compared to baseline values. Neither tDCS + seated (p = 0.173) nor sham + walking (p = 0.826) influenced this outcome. Similar results were seen for other gait measures and for Stroop performance. Sway was not affected by tDCS. CONCLUSIONS: tDCS delivered during the performance of challenging walking decreased the dual-task cost to walking in older adults when they were tested just after stimulation. These results support the existence of a state-dependent impact of neuro-modulation that may set the stage for a more optimal neuro-rehabilitation. TRIAL REGISTRATION: Clinical Trials Gov Registrations Number: NCT02954328.

Anxiolytic treatment but not anxiety itself causes hyponatremia among anxious patients.

The aim of the study was to define whether anxiety itself or only the treatment with anxiolytic medication is risk factor for hyponatremia and overhydration.A case-control study of patients with a diagnosis of anxiety who received a selective serotonin reuptake inhibitor (SSRI). Serum sodium, urea to creatinine ratio, and odds ratio (OR) of hyponatremia and overhydration before initiation of treatment were compared to those of a control group of participants. Laboratory tests were also examined for changes following treatment with an SSRI. All blood tests were conducted from January 1, 2001 until December 31, 2017. Subjects were selected from a large electronic database, insuring 2 million Israelis. A total of 7211 patients with a diagnosis of anxiety who have received a prescription for an SSRI were identified; 3634 were excluded mostly due to other conditions that could cause hyponatremia, and 3520 participants were included in the case group. The control group consisted of 6985 age and gender matched participants who did not have a diagnosis of anxiety or any other exclusion criteria.Mean serum sodium levels were elevated in cases before the initiation of SSRIs; sodium: case 139.3 (137.3-141.3), control 139.2 (137.06-141.26) mmol/L (P = .01). The OR of hyponatremia was 0.89 for the case group (P = .004). Treatment with SSRIs decreased mean serum sodium (139.3-139.1 mmol/L; P = .0001) and increased by 50% the rate of hyponatremia (2.6-3.9% P = .024).It is the use of SSRIs and not anxiety itself that causes hyponatremia among anxious patients.

Correlates of gastroenterology health-services utilization among patients with gastroesophageal reflux disease: a large database analysis.

BACKGROUND: Gastroesophageal reflux disease (GERD) is associated with high utilization of health care services. Diagnostic tests usually are not required to establish GERD diagnosis, but endoscopy is recommended for patients with alarm symptoms such as dysphagia and unintentional weight loss, and those whose symptoms are not relieved by proton pump inhibitors (PPIs) therapy. Evidence on the correlates of utilization of gastroenterology health services among GERD patients is limited. The study aim was to examine associations of patient and physician's characteristics with high utilization of gastroenterology services. METHODS: In a cross-sectional study using the database of the second largest integrated care organization in Israel, data of all adult GERD patients (N = 75,219) in 2012-2015 were analyzed. High utilization of services was assessed using two dependent variables analyzed separately: undergoing two or more gastroscopies or having six or more visits to a gastroenterology consultant during the study-period. RESULTS: Overall, 11,261 (15.0%) patients had two or more gastroscopies and 23,703 (31.5%) had six or more visits to a gastroenterology consultant. The likelihood of high utilization of gastroscopy increased with age; in immigrants from the Former Soviet Union versus patients who were born in Israel; residents of Jerusalem, the south, the north and Haifa districts versus the center district; in patients with high PPI purchases, and in patients who belonged to clinics in which the physician-manger had no board certification. The correlates were similar for visits to a gastroenterology consultant. CONCLUSIONS: Patient and physician's characteristics were related to high utilization of gastroenterology services among GERD patients. The associations with age and country of birth might reflect more severe disease. The regional differences warrant further research and interventions at the district level. Training in gastroenterology of primary care physicians without a board certification is warranted.