scholarly journals The role of hippocampal theta oscillations in working memory impairment in multiple sclerosis

2020 ◽  
Author(s):  
Lars Costers ◽  
Jeroen Van Schependom ◽  
Jorne Laton ◽  
Johan Baijot ◽  
Martin Sjøgård ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Working Memory ◽  
Healthy Subjects ◽  
Neuronal Damage ◽  
Hippocampal Damage ◽  
Theta Power ◽  
Power Increase ◽  
Neurophysiological Mechanisms ◽  
The Right ◽  
Hippocampal Theta

AbstractWorking memory (WM) problems are frequent in persons with multiple sclerosis (MS). Even though hippocampal damage has been repeatedly shown to play an important role, the underlying neurophysiological mechanisms remain unclear. This study aimed to investigate the neurophysiological underpinnings of WM impairment in MS using magnetoencephalography (MEG) data from a verbal n-back task. We analysed MEG recordings of 79 MS patients and 38 healthy subjects through event-related fields (ERFs) and theta (4-8 Hz) and alpha (8-13 Hz) oscillatory processes. Data was source reconstructed and parcellated based on previous findings in the healthy subject sample. MS patients showed a smaller maximum theta power increase in the right hippocampus between 0 and 400 ms than healthy subjects (p = 0.014). This theta power increase value correlated strongly and negatively with reaction time on the task in MS (r = −0.32, p = 0.029). Evidence was provided that this relationship could not be explained by a confounding relationship with MS-related neuronal damage. This study provides the first neurophysiological evidence of the influence of hippocampal dysfunction on WM performance in MS.

scholarly journals The role of hippocampal theta oscillations in working memory impairment in multiple sclerosis

2020 ◽  
Author(s):  
Lars Costers ◽  
Jeroen Van Schependom ◽  
Jorne Laton ◽  
Johan Baijot ◽  
Martin Sjøgård ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Working Memory ◽  
Memory Impairment ◽  
Theta Oscillations ◽  
Hippocampal Theta

Electromyographic activity to keep a lower limb in a raised position in healthy subjects and subjects with multiple sclerosis

2008 ◽  
Vol 14 (5) ◽  
pp. 691-693
Author(s):  
R Gatti ◽  
M Corti ◽  
S Govetto ◽  
K Bonzani ◽  
S Boccardi
Keyword(s):  
Multiple Sclerosis ◽  
Supine Position ◽  
Lower Limb ◽  
Healthy Subjects ◽  
Biceps Femoris ◽  
Abdominal Muscles ◽  
Electromyographic Activity ◽  
Hip Kinematics ◽  
The Difference ◽  
The Right

The objective of this work was to assess the activation of the stabilization muscles used to keep one lower limb raised from a supine position, in healthy subjects and in subjects with multiple sclerosis (MS) in two different conditions. The test required subjects to keep the right lower limb at 45° from the supine position on a horizontal bed plane, with the knee extended. The position was reached in two ways: by raising the right limb (A), and by resting the left lower limb on the bed after both limbs had been raised (B). During the test, pelvis and hip kinematics and the surface electromyographic (sEMG) activity were acquired. Fourteen healthy subjects and 14 subjects with multiple sclerosis were included in the study. Results showed that in the A condition, healthy subjects had a greater activation of the biceps femoris than the abdominal muscles, while in the B condition the difference between the two muscles decreased. In the MS group there was no difference in muscular activation for the two conditions. The data show that in the MS subjects there is an alteration of the stabilization muscles with regard the quality of the activation. Starting from these data new exercises of motor rehabilitation in subjects with multiple sclerosis could be recommended.

The N3 potential compared to sound and galvanic vestibular evoked myogenic potential in healthy subjects and in multiple sclerosis patients

2007 ◽  
Vol 17 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Maurizio Versino ◽  
Laura Ranza ◽  
Silvia Colnaghi ◽  
Roberto Alloni ◽  
Roberto Callieco ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Healthy Subjects ◽  
Reference Range ◽  
Evoked Response ◽  
Vestibular Evoked Myogenic Potential ◽  
Auditory Evoked Response ◽  
Myogenic Potential ◽  
The Mean ◽  
The Right ◽  
Multiple Sclerosis Patients

Both sound (s-) and galvanic (g-) vestibular-evoked myogenic potential (VEMP) enable us to study the saccular pathways. However, the VEMP can be abnormal for non-vestibular factors, such as insufficient activation of the sterno-cleido-mastoid (SCM) muscle or a lesion that involves the accessory nucleus and/or nerve or the SCM muscle. These drawbacks do not affect another technique that evaluates the saccular function: the N3 potential. We recorded both the s- and the g-VEMP and the N3 potential in a group of 31 healthy subjects to establish a reference range. The N3 potential and the s-VEMP were recordable bilaterally from all the subjects, whereas the g-VEMP was undetectable uni- or bilaterally in 7 subjects. The latency and amplitude values of the s-VEMP did not differ from those of the g-VEMP. For all three techniques, the latency and amplitude values from the right and from the left recording and/or stimulation side were the same. We suggest using normative latency and amplitude values based on the mean and ratio of the right- and left-side values. The s-VEMP, the N3 potential and the auditory evoked response (ABR) were compared in 15 subjects suffering from multiple sclerosis. The three techniques detected a similar number of abnormalities, but these abnormalities were not correlated. This suggests that these different techniques should be regarded as complementary in evaluating saccular function.

Human Cerebral Potentials During Motor Training Under Different Forms of Sensory Feedback

1999 ◽  
Vol 13 (4) ◽  
pp. 234-244
Author(s):  
Uwe Niederberger ◽  
Wolf-Dieter Gerber
Keyword(s):  
Healthy Subjects ◽  
Sensory Feedback ◽  
Motor Task ◽  
Tactile Feedback ◽  
Proprioceptive Feedback ◽  
Motor Training ◽  
Feedback Group ◽  
Emg Feedback ◽  
The Right ◽  
Training Success

Abstract In two experiments with four and two groups of healthy subjects, a novel motor task, the voluntary abduction of the right big toe, was trained. This task cannot usually be performed without training and is therefore ideal for the study of elementary motor learning. A systematic variation of proprioceptive, tactile, visual, and EMG feedback was used. In addition to peripheral measurements such as the voluntary range of motion and EMG output during training, a three-channel EEG was recorded over Cz, C3, and C4. The movement-related brain potential during distinct periods of the training was analyzed as a central nervous parameter of the ongoing learning process. In experiment I, we randomized four groups of 12 subjects each (group P: proprioceptive feedback; group PT: proprioceptive and tactile feedback; group PTV: proprioceptive, tactile, and visual feedback; group PTEMG: proprioceptive, tactile, and EMG feedback). Best training results were reported from the PTEMG and PTV groups. The movement-preceding cortical activity, in the form of the amplitude of the readiness potential at the time of EMG onset, was greatest in these two groups. Results of experiment II revealed a similar effect, with a greater training success and a higher electrocortical activation under additional EMG feedback compared to proprioceptive feedback alone. Sensory EMG feedback as evaluated by peripheral and central nervous measurements appears to be useful in motor training and neuromuscular re-education.

Comparison of the Aditus ad Antrum Diameter on CT between Patients with Chronic Otitis Media and Healthy Individuals

2019 ◽  
Vol 15 (10) ◽  
pp. 990-993 ◽  
Author(s):  
Elif Gündoğdu ◽  
Uğur Toprak
Keyword(s):  
Computed Tomography ◽  
Otitis Media ◽  
Middle Ear ◽  
Healthy Subjects ◽  
Normal Values ◽  
Chronic Otitis Media ◽  
Healthy Individuals ◽  
Inner Diameter ◽  
Male Patients ◽  
The Right

Background: The middle ear cavity is ventilated through the aditus ad antrum. Aditus blockage contributes to the pathology of otitis media. Objective: To determine the normal values of the aditus ad antrum diameter on computed tomography and to investigate its relationship with chronic otitis media and related pathologies (tympanosclerosis and myringosclerosis). Methods: The temporal CT images of 162 individuals were evaluated retrospectively. In the axial sections, the inner diameter of the aditus was measured at the narrowest point at the cortex. The differences in diameter were compared between diseased and healthy ears. Results: In healthy individuals, the diameter was narrower in women. There was no difference between the right and left ears in healthy subjects. No correlation was found between age and diameter. In male patients with myringosclerosis, the diameter was slightly narrower on both sides but more marked on the left. In female patients with myringosclerosis, the diameter in both ears was slightly narrower. In cases of otitis media and tympanosclerosis, the diameter was less than that of healthy individuals, despite the lack of statistically significant result in all cases. Conclusion: The aditus ad antrum was narrower in diseased ears, indicating that a blocked aditus may contribute to the development of otitis media, as well as mucosal diseases.

scholarly journals Association between Hippocampal Volume and Working Memory in 10,000+ 9–10-Year-Old Children: Sex Differences

Children ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 411
Author(s):  
Shervin Assari ◽  
Shanika Boyce ◽  
Tanja Jovanovic
Keyword(s):  
Working Memory ◽  
Sex Differences ◽  
Parental Education ◽  
Predictor Variable ◽  
National Sample ◽  
Hippocampal Volume ◽  
Study Data ◽  
Cross Sectional ◽  
The Right

Aim: This study tested sex differences in the association between hippocampal volume and working memory of a national sample of 9–10-year-old children in the US. As the hippocampus is functionally lateralized (especially in task-related activities), we explored the results for the right and the left hippocampus. Methods: This is a cross-sectional study using the Adolescent Brain Cognitive Development (ABCD) Study data. This analysis included baseline ABCD data (n = 10,093) of children between ages 9 and 10 years. The predictor variable was right and left hippocampal volume measured by structural magnetic resonance imaging (sMRI). The primary outcome, list sorting working memory, was measured using the NIH toolbox measure. Sex was the moderator. Age, race, ethnicity, household income, parental education, and family structure were the covariates. Results: In the overall sample, larger right (b = 0.0013; p < 0.001) and left (b = 0.0013; p < 0.001) hippocampal volumes were associated with higher children’s working memory. Sex had statistically significant interactions with the right (b = −0.0018; p = 0.001) and left (b = −0.0012; p = 0.022) hippocampal volumes on children’s working memory. These interactions indicated stronger positive associations between right and left hippocampal volume and working memory for females compared to males. Conclusion: While right and left hippocampal volumes are determinants of children’s list sorting working memory, these effects seem to be more salient for female than male children. Research is needed on the role of socialization, sex hormones, and brain functional connectivity as potential mechanisms that may explain the observed sex differences in the role of hippocampal volume as a correlate of working memory.

scholarly journals Are visual working memory and episodic memory distinct processes? Insight from stroke patients by lesion-symptom mapping

2021 ◽  
Author(s):  
Selma Lugtmeijer ◽  
◽  
Linda Geerligs ◽  
Frank Erik de Leeuw ◽  
Edward H. F. de Haan ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Visual Working Memory ◽  
Visual Memory ◽  
Right Hemisphere ◽  
Memory Task ◽  
Stroke Patients ◽  
Lesion Symptom Mapping ◽  
Criterion Setting ◽  
The Right

AbstractWorking memory and episodic memory are two different processes, although the nature of their interrelationship is debated. As these processes are predominantly studied in isolation, it is unclear whether they crucially rely on different neural substrates. To obtain more insight in this, 81 adults with sub-acute ischemic stroke and 29 elderly controls were assessed on a visual working memory task, followed by a surprise subsequent memory test for the same stimuli. Multivariate, atlas- and track-based lesion-symptom mapping (LSM) analyses were performed to identify anatomical correlates of visual memory. Behavioral results gave moderate evidence for independence between discriminability in working memory and subsequent memory, and strong evidence for a correlation in response bias on the two tasks in stroke patients. LSM analyses suggested there might be independent regions associated with working memory and episodic memory. Lesions in the right arcuate fasciculus were more strongly associated with discriminability in working memory than in subsequent memory, while lesions in the frontal operculum in the right hemisphere were more strongly associated with criterion setting in subsequent memory. These findings support the view that some processes involved in working memory and episodic memory rely on separate mechanisms, while acknowledging that there might also be shared processes.

scholarly journals The Brief International Cognitive Assessment in Multiple Sclerosis (BICAMS): Validation in Arabic and Lebanese Normative Values

2021 ◽  
pp. 1-10
Author(s):  
Hala Darwish ◽  
Pia Zeinoun ◽  
Natali Farran ◽  
Husam Ghusn ◽  
Bassem Yamout ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Psychometric Properties ◽  
Cognitive Assessment ◽  
Healthy Subjects ◽  
Good Evidence ◽  
Normative Values ◽  
Arabic Version ◽  
Retest Reliability ◽  
Test Retest Reliability ◽  
Healthy Participants

Abstract Objective: Multiple sclerosis (MS) is often associated with cognitive deficits. Accurate evaluation of the MS patients’ cognitive performance is essential for diagnosis and treatment recommendation. The Brief International Cognitive Assessment in Multiple Sclerosis (BICAMS), widely used cognitive testing battery, examines processing speed, verbal and visuospatial learning, and memory. Our study aims to examine the psychometric properties of an Arabic version of the BICAMS and to provide normative values in a Lebanese sample. Method: The BICAMS, comprised of the Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), and a newly developed verbal learning/memory test, the Verbal Memory Arabic Test (VMAT), were administered on healthy subjects and MS patients. The sample consisted of 180 healthy individuals, of whom 63 were retested after 2–3 weeks. Forty-three MS patients matched with 43 healthy subjects based on age, sex, and years of education were assessed. A sample of 10 MS patients was also examined on two occasions. Test–retest reliability and criterion-related validity were examined, and regression-based norms were derived. Results: The test–retest correlations showed good evidence of reliability with coefficients ranging between 0.64 and 0.73 in the healthy sample, and between 0.43 and 0.92 in the MS sample. The BICAMS was able to discriminate between MS patients and matched healthy participants on the SDMT and BVMT-R. Normative data were comparable to other studies. Conclusions: This new Arabic version of the BICAMS shows initial good psychometric properties. While good evidence of VMAT’s reliability was shown in the healthy participants, less test–retest reliability in this tool was seen in the MS group, and partial criterion-related validity was evident. This renders further examination of the VMAT. We provide regression-based norms for a Lebanese sample and encourage the use of this battery in both research and clinical settings.

scholarly journals Biomechanical analysis of an unpowered hip flexion orthosis on individuals with and without multiple sclerosis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ross M. Neuman ◽  
Staci M. Shearin ◽  
Karen J. McCain ◽  
Nicholas P. Fey
Keyword(s):  
Multiple Sclerosis ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Assistive Technologies ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Foot Drop ◽  
Plantar Flexors ◽  
Hip Flexion

Abstract Background Gait impairment is a common complication of multiple sclerosis (MS). Gait limitations such as limited hip flexion, foot drop, and knee hyperextension often require external devices like crutches, canes, and orthoses. The effects of mobility-assistive technologies (MATs) prescribed to people with MS are not well understood, and current devices do not cater to the specific needs of these individuals. To address this, a passive unilateral hip flexion-assisting orthosis (HFO) was developed that uses resistance bands spanning the hip joint to redirect energy in the gait cycle. The purpose of this study was to investigate the short-term effects of the HFO on gait mechanics and muscle activation for people with and without MS. We hypothesized that (1) hip flexion would increase in the limb wearing the device, and (2) that muscle activity would increase in hip extensors, and decrease in hip flexors and plantar flexors. Methods Five healthy subjects and five subjects with MS walked for minute-long sessions with the device using three different levels of band stiffness. We analyzed peak hip flexion and extension angles, lower limb joint work, and muscle activity in eight muscles on the lower limbs and trunk. Single-subjects analysis was used due to inter-subject variability. Results For subjects with MS, the HFO caused an increase in peak hip flexion angle and a decrease in peak hip extension angle, confirming our first hypothesis. Healthy subjects showed less pronounced kinematic changes when using the device. Power generated at the hip was increased in most subjects while using the HFO. The second hypothesis was not confirmed, as muscle activity showed inconsistent results, however several subjects demonstrated increased hip extensor and trunk muscle activity with the HFO. Conclusions This exploratory study showed that the HFO was well-tolerated by healthy subjects and subjects with MS, and that it promoted more normative kinematics at the hip for those with MS. Future studies with longer exposure to the HFO and personalized assistance parameters are needed to understand the efficacy of the HFO for mobility assistance and rehabilitation for people with MS.

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