A Single Bout of High-Intensity Interval Training Reduces Awareness of Subsequent Hypoglycemia in Patients with Type 1 Diabetes.

High-intensity interval training (HIIT) gains increasing popularity in patients with diabetes. HIIT acutely increases plasma lactate levels. This may be important, since administration of lactate during hypoglycemia suppresses symptoms and counterregulation, whilst preserving cognitive function. We tested the hypothesis that HIIT acutely reduces awareness of hypoglycemia and attenuates hypoglycemia-induced cognitive dysfunction. In a randomized crossover trial, patients with type 1 diabetes and normal awareness of hypoglycemia (NAH), patients with impaired awareness of hypoglycemia (IAH), and healthy participants (n=10 per group) underwent a hyperinsulinemic-hypoglycemic (2.6 mmol/L) clamp, either after a HIIT session or after seated rest. Compared to rest, HIIT reduced symptoms of hypoglycemia in patients with NAH, but not in healthy participants or patients with IAH. HIIT attenuated hypoglycemia-induced cognitive dysfunction, which was mainly driven by changes in the NAH subgroup. HIIT suppressed cortisol and growth hormone responses, but not catecholamine responses to hypoglycemia. The present findings demonstrate that a single HIIT session rapidly reduces awareness of subsequent hypoglycemia in patients with type 1 diabetes and NAH, but not in patients with IAH, and attenuates hypoglycemia-induced cognitive dysfunction. The role of exercise-induced lactate in mediating these effects, potentially serving as an alternative fuel for the brain, should be further explored

Accelerated forgetting? An evaluation on the use of long-term forgetting rates in patients with memory problems

The main focus of this review was to evaluate whether long-term forgetting rates (delayed tests days to weeks after initial learning) are a more sensitive measure to detect memory problems in various patient groups than standard delayed recall measures. It has been suggested that accelerated forgetting might be characteristic for epilepsy patients, but little research has been performed within other populations. Here, we identified ten studies in a wide range of brain injured patient groups, whose long-term forgetting patterns were compared to that of healthy controls. Signs of accelerated forgetting were found within two studies. The results of seven studies showed normal forgetting over time for the patient groups. However, most of the studies used only a recognition procedure, after optimizing initial learning. Based on the results, we discuss recommendations for assessing long-term forgetting and the need for future research to truly evaluate the usefulness for clinical practice

“Make no mistake”: Errorless learning and its application in rehabilitation

When errorless (EL) learning was first conceived and applied in brain injury rehabilitation, it was in the context of trying to improve the lives of people who suffered from the most severe form of memory impairment: amnesia. The severity of the memory impairment in these patients is profound, and its extent global in affecting capacity to remember any novel information seen or heard. But there was a silver lining. Despite the major deficiency in recollection, these patients were able to demonstrate newly acquired knowledge unconsciously, or implicitly, on indirect tests of memory (e.g., as shown in mirror reading, word fragment completion tasks), and sometimes were able to do so at a level that was equivalent to that of people without memory impairment. For Baddeley and Wilson, this revealed a vital strength that they could capitalize on to help reduce the impact of the profound learning deficits these patients experienced (Baddeley, 1992; Baddeley & Wilson, 1994). The reasoning here is that if implicit memory is preserved, then new learning in these patients would be best supported under conditions that facilitate this kind of memory processing. The question this poses though is what form of learning can achieve this goal?

The Box Task: A tool to design experiments for assessing visuospatial working memory

The present paper describes the Box Task, a paradigm for the computerized assessment of visuospatial working memory. In this task, hidden objects have to be searched by opening closed boxes that are shown at different locations on the computer screen. The set size (i.e., number of boxes that must be searched) can be varied and different error scores can be computed that measure specific working memory processes (i.e., the number of within-search and between-search errors). The Box Task also has a developer’s mode in which new stimulus displays can be designed for use in tailored experiments. The Box Task comes with a standard set of stimulus displays (including practice trials, as well as stimulus displays with 4, 6, and 8 boxes). The raw data can be analyzed easily and the results of individual participants can be aggregated into one spreadsheet for further statistical analyses

Working with error in rehabilitation practice: Making the most of errorless and error-based approaches

At first glance, it may appear a little unusual to focus a volume entirely on the contribution of error to learning. There are clearly many other influences on memory; such as conditioning, cognitive control, emotion, organization, and meaning. Yet few have formed the basis of a volume in their own right. So, why does managing error deserve such attention? One answer is that because errors are so common in a range of learning contexts and throughout our lives, their influence is important to understand. Another answer, and one to which this volume attests, is that errors deserve this attention because of the potential effect that they can have on the independence, motivation, and wider behaviour of those whose memory and learning has become vulnerable. If errors are a common experience for all, then their frequency and impact will be far greater on those whose learning is significantly impaired

Brain Activation during Associative Short-Term Memory Maintenance is Not Predictive for Subsequent Retrieval

Performance on working memory (WM) tasks may partially be supported by long-term memory (LTM) processing. Hence, brain activation recently being implicated in WM may actually have been driven by (incidental) LTM formation. We examined which brain regions actually support successful WM processing, rather than being confounded by LTM processes, during the maintenance and probe phase of a WM task. We administered a four-pair (faces and houses) associative delayed-match-to-sample (WM) task using event-related fMRI and a subsequent associative recognition LTM task, using the same stimuli. This enabled us to analyze subsequent memory effects for both the WM and the LTM test by contrasting correctly recognized pairs with incorrect pairs for either task. Critically, with respect to the subsequent WM effect, we computed this analysis exclusively for trials that were forgotten in the subsequent LTM recognition task. Hence, brain activity associated with successful WM processing was less likely to be confounded by incidental LTM formation. The subsequent LTM effect, in contrast, was analyzed exclusively for pairs that previously had been correctly recognized in the WM task, disclosing brain regions involved in successful LTM formation after successful WM processing. Results for the subsequent WM effect showed no significantly activated brain areas for WM maintenance, possibly due to an insensitivity of fMRI to mechanisms underlying active WM maintenance. In contrast, a correct decision at WM probe was linked to activation in the retrieval success network (anterior and posterior midline brain structures). The subsequent LTM analyses revealed greater activation in left dorsolateral prefrontal cortex and posterior parietal cortex in the early phase of the maintenance stage. No supra-threshold activation was found during the WM probe. Together, we obtained clearer insights in which brain regions support successful WM and LTM without the potential confound of the respective memory system

An exploratory study of the effects of spatial working-memory load on prefrontal activation in low- and high-performing elderly

Older adults show more bilateral prefrontal activation during cognitive performance than younger adults, who typically show unilateral activation. This over-recruitment has been interpreted as compensation for declining structure and function of the brain. Here we examined how the relationship between behavioral performance and prefrontal activation is modulated by different levels of working-memory load. Eighteen healthy older adults (70.8 ± 5.0 years; MMSE 29.3 ± 0.9) performed a spatial working-memory task (n-back). Oxygenated ([O2Hb]) and deoxygenated ([HHb]) hemoglobin concentration changes were registered by two functional Near-Infrared Spectroscopy (fNIRS) channels located over the left and right prefrontal cortex. Increased working-memory load resulted in worse performance compared to the control condition. [O2Hb] increased with rising working-memory load in both fNIRS channels. Based on the performance in the high working-memory load condition, the group was divided into low and high performers. A significant interaction effect of performance level and hemisphere on [O2Hb] increase was found, indicating that high performers were better able to keep the right prefrontal cortex engaged under high cognitive demand. Furthermore, in the low performers group, individuals with a larger decline in task performance from the control to the high working-memory load condition had a larger bilateral increase of [O2Hb]. The high performers did not show a correlation between performance decline and working-memory load related prefrontal activation changes. Thus, additional bilateral prefrontal activation in low performers did not necessarily result in better cognitive performance. Our study showed that bilateral prefrontal activation may not always be successfully compensatory. Individual behavioral performance should be taken into account to be able to distinguish successful and unsuccessful compensation or declined neural efficiency

Neuropsychiatric symptoms in Korsakoff's syndrome

We aim to study the manifestation and management of neuropsychiatric symptoms (NPS) such as agitation and apathy in Korsakoff's syndrome. First, we will investigate the prevalence and course of NPS in institutionalized patients with Korsakoff's syndrome. Second, we will examine clinical and demographic predictors of NPS by studying the relationship with cognitive deficits, illness-insight, and demographic characteristics. Finally, we will evaluate an existing training for clinicians to improve the early recognition and management of NPS in Korsakoff's syndrome