Effect of acupuncture on unilateral spatial neglect after stroke: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To systematically evaluate the effects of acupuncture in patients with unilateral spatial neglect (USN) after stroke. DATA SOURCES: Relevant English- and Chinese- language studies published until 12th February 2022, were retrieved from China National Knowledge Infrastructure (CNKI), Wanfang, China Scientific Journals Database (VIP), SinoMed, PubMed, Cochrane Library, Embase, Web of Science and OVID. REVIEW METHODS: Randomized controlled trials (RCTs) assessing the effects of acupuncture in patients with USN after stroke were included. Two researchers independently identified eligible studies and extracted the data. The methodological quality of the studies was evaluated using the Cochrane Handbook for Systematic Reviews of Interventions v5.1.0. RESULTS: Twelve studies (731 participants) were included. The meta-analysis found that compared with the control group, acupuncture increased MMSE, BI, MBI, and FMA scores and reduced the USN scores (all P < 0.05). These results indicated that acupuncture improved cognitive function, activities of daily living (ADLs), and motor function and relieved the degree of USN in patients with USN after stroke. CONCLUSION: Acupuncture could promote the rehabilitation of cognitive function, ADLs, and motor function and relieve the symptoms of USN in patients with USN after stroke. It may be a good complementary treatment to rehabilitation therapy for USN.

Effects of prism adaptation on auditory spatial attention in patients with left unilateral spatial neglect: a non-randomized pilot trial.

A short period of adaptation to a prismatic shift of the visual field to the right briefly but significantly improves left unilateral spatial neglect. Additionally, prism adaptation affects multiple modalities, including processes of vision, auditory spatial attention, and sound localization. This non-randomized, single-center, controlled trial aimed to examine the immediate effects of prism adaptation on the sound-localization abilities of patients with left unilateral spatial neglect using a simple source localization test. Subjects were divided by self-allocation into a prism-adaptation group (n = 11) and a control group (n = 12). At baseline, patients with left unilateral spatial neglect showed a rightward deviation tendency in the left space. This tendency to right-sided bias in the left space was attenuated after prism adaptation. However, no changes were observed in the right space of patients with left unilateral spatial neglect after prism adaptation, or in the control group. Our results suggest that prism adaptation improves not only vision and proprioception but also auditory attention in the left space of patients with left unilateral spatial neglect. Our findings demonstrate that a single session of prism adaptation can significantly improve sound localization in patients with left unilateral spatial neglect. However, in this study, it was not possible to accurately determine whether the mechanism was a chronic change in head orientation or a readjustment of the spatial representation of the brain; thus, further studies need to be considered.

An Active Inference Approach to Interoceptive Psychopathology.

Interoception refers to the process by which the nervous system senses and integrates signals originating from within the body, providing a momentary mapping of the body's internal landscape and its relationship to the outside world. Active inference is based on the premise that afferent sensory input to the brain is constantly shaped and modified by prior expectations. In this review we propose that interoceptive psychopathology results from two primary interoceptive dysfunctions: First, individuals have abnormally strong expectations of the situations that elicit bodily change (i.e., hyperprecise priors), and second, they have great difficulty adjusting these expectations when the environment changes (i.e., context rigidity). Here we discuss how these dysfunctions potentially manifest in mental illness and how interventions aimed at altering interoceptive processing can help the brain create a more realistic model of its internal state.

Increased Alpha-Rhythm Dynamic Range Promotes Recovery from Visuospatial Neglect: A Neurofeedback Study.

Despite recent attempts to use electroencephalogram (EEG) neurofeedback (NFB) as a tool for rehabilitation of motor stroke, its potential for improving neurological impairments of attention-such as visuospatial neglect-remains underexplored. It is also unclear to what extent changes in cortical oscillations contribute to the pathophysiology of neglect, or its recovery. Utilizing EEG-NFB, we sought to causally manipulate alpha oscillations in 5 right-hemisphere stroke patients in order to explore their role in visuospatial neglect. Patients trained to reduce alpha oscillations from their right posterior parietal cortex (rPPC) for 20 minutes daily, over 6 days. Patients demonstrated successful NFB learning between training sessions, denoted by improved regulation of alpha oscillations from rPPC. We observed a significant negative correlation between visuospatial search deficits (i.e., cancellation test) and reestablishment of spontaneous alpha-rhythm dynamic range (i.e., its amplitude variability). Our findings support the use of NFB as a tool for investigating neuroplastic recovery after stroke and suggest reinstatement of intact parietal alpha oscillations as a promising target for reversing attentional deficits. Specifically, we demonstrate for the first time the feasibility of EEG-NFB in neglect patients and provide evidence that targeting alpha amplitude variability might constitute a valuable marker for clinical symptoms and self-regulation.

Adding transcutaneous electrical nerve stimulation to visual scanning training does not enhance treatment effect on hemispatial neglect: a randomized, controlled, double-blind study.

BACKGROUND: Left-sided transcutaneous electrical nerve stimulation (TENS) increases right hemispheric activity, which may improve the rehabilitative outcome of hemispatial neglect. OBJECTIVE: To examine the behavioral effect of electrical stimulation of the nerve afferents of the left hand during early neuropsychological rehabilitation of post-stroke patients with hemispatial neglect. METHODS: This randomized, controlled, double-blind study included 29 patients (enrolled in the experimental or control group) with left hemispatial neglect after right hemispheric stroke. For 3 weeks, patients received 15 therapeutic sessions involving TENS (active or sham) with a mesh glove applied on the entire left hand during the first 30 minutes of a 45-minute conventional visual scanning training (VST). Signs of hemispatial neglect were assessed using a psychometric test before and after treatment. RESULTS: Univariate analysis of covariance revealed that differences between the control and experimental groups were not significant after treatment (F(1, 22) = 0.294, P = 0.593) when adjusted for pre-treatment scores and time since stroke onset. This suggested that electrical stimulation failed to mitigate the severity of hemispatial neglect symptoms. CONCLUSION: Our study did not provide evidence of the effectiveness of TENS when added to VST during early rehabilitation for patients with post-stroke hemispatial neglect. Other techniques (applied alone or together) should be sought to improve recovery in this population.

Mirror therapy in unilateral neglect after stroke (MUST trial): a randomized controlled trial.

OBJECTIVE: We explored the effectiveness of mirror therapy (MT) in the treatment of unilateral neglect in stroke patients. METHODS: This is an open, blinded endpoint, randomized controlled trial carried out from January 2011 to August 2013. We included stroke patients with thalamic and parietal lobe lesions with unilateral neglect 48 hours after stroke. Patients were randomized to the MT group or the control group (sham MT), and both the groups received limb activation. Patients received treatment for 1-2 hours a day 5 days a week for 4 weeks. The primary outcome was unilateral neglect assessed by a blinded assessor using the star cancellation test, the line bisection test, and a picture identification task at 1, 3, and 6 months. This study was registered at http://clinicaltrials.gov (NCT 01735877). RESULTS: Forty-eight patients were randomized to MT (n = 27) or the control group (n = 21). Improvement in scores on the star cancellation test over 6 months was greater in the MT group (mean difference 23, 95% confidence interval [CI] 19-28; p < 0.0001). Similarly, improvement in the MT group was observed in the scores on the picture identification task (mean difference 3.2, 95% CI 2.4-4.0; p < 0.0001) and line bisection test (mean difference 8.6, 95% CI 2.7-14.6; p = 0.006). CONCLUSIONS: In patients with stroke, MT is a simple treatment that improves unilateral neglect. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with neglect from thalamic and parietal lobe strokes, MT improves neglect.

A Chinese patient with pusher syndrome and unilateral spatial neglect syndrome.

OBJECTIVE: To observe clinical manifestations, behavioral characteristics, and effects of rehabilitation on a patient with pusher syndrome and unilateral spatial neglect caused by right thalamic hemorrhage. METHODS: Assessment of pusher syndrome was made by the Scale for Contraversive pushing (SCP), and unilateral spatial neglect syndrome was diagnosed using line cancellation, letter and star cancellation, line bisection tests and copy and continuation of graphic sequence test. Behavioral therapy, occupational therapy, reading training and traditional Chinese medicine methods were adopted for treatment of pusher syndrome and unilateral spatial neglect. RESULTS: The patient showed typical pusher syndrome and unilateral spatial neglect symptoms. The pusher syndrome and unilateral spatial neglect symptoms were significantly improved following rehabilitation treatments. CONCLUSIONS: Pusher syndrome and unilateral spatial neglect syndrome occurred simultaneously after right thalamic hemorrhage. Early rehabilitation therapy can reduce the symptoms of pusher syndrome and unilateral spatial neglect syndrome and improve motor function.

Effects of dual transcranial direct current stimulation on post-stroke unilateral visuospatial neglect.

Based on the interhemispheric inhibition model of unilateral visuospatial neglect (USN) after stroke, the effects of dual-mode transcranial direct current stimulation (tDCS) over the parietal cortices were assessed in a double-blind random-order cross-over experiment. Ten chronic right hemispheric stroke patients (4 men; mean age: 62.6 years) with USN were recruited. All participants underwent three randomly arranged tDCS sessions: (1) dual-mode, anodal tDCS over the right posterior parietal cortex (PPC) and cathodal tDCS over the left PPC; (2) single-mode, anodal tDCS over the right PPC; and (3) sham mode. Each session lasted 20min. Before and immediately after the stimulation, a line bisection test and star cancelation test were carried out. In the line bisection test, significant improvements were observed after both the dual- and the single-mode tDCS (p<0.05), but not after sham stimulation. Statistical analysis showed a significant interaction between time and tDCS mode, where the dual tDCS had a stronger effect than the single or sham stimulation modes (p<0.05). The star cancelation test did not show any significant change. These results suggest that dual tDCS over the bilateral PPC is an effective method for the treatment of USN in stroke patients.

Don't neglect 'neglect'- an update on post stroke neglect.

OBJECTIVES: Post-stroke neglect is common and an independent predictor of functional outcome. Assessment of neglect is very demanding, the treatment extremely difficult and the literature vast; we performed a literature search for all aspects of this difficult subject. METHODS: We searched the PubMed, EMBASE databases and historical manuals for authoritative studies on post stroke neglect between 1951 and 2011. FINDINGS: There is a great dearth of randomised controlled data on neglect because standardised assessment does not occur frequently. Eighty-eight manuscripts were identified in the literature, which were quite heterogeneous in their content and addressing diverse aspects of this clinical entity. INTERPRETATION AND IMPLICATIONS: The most important historical papers were selected along with the most widely accepted and proven strategies for assessment and treatment. Standardised assessment of neglect does not always occur, but several useful strategies are available and are described in the following sections.

Anosognosia and neglect respond differently to the same treatments.

Different techniques, such as optokinetic stimulation, adaptation to prismatic shift of the visual field to the right, or transcutaneous electrical nerve stimulation (TENS), have been shown to alleviate neglect, at least temporarily. We assessed the effect of these techniques on anosognosia and whether their therapeutic effect, if any, matches that on neglect. The effect of the three types of treatment on anosognosia and neglect was investigated in five patients presenting with both severe anosognosia and neglect. Patient 1 was treatment responsive to anosognosia but not to neglect, whereas patients 4 and 5 showed the reverse pattern, i.e., they were treatment responsive to neglect but not to anosognosia. This "treatment response bias" proved to be a valid means to investigate different effects of treatments in the same patient.

Noninvasive transorbital alternating current stimulation improves subjective visual functioning and vision-related quality of life in optic neuropathy.

BACKGROUND: Noninvasive repetitive transorbital alternating current stimulation (rtACS) can improve visual field size in patients with optic nerve damage, but it is not known if this is of subjective relevance. We now assessed patient reported outcomes to determine the association between visual field changes and vision-related quality of life (QoL). METHODS: Patients having visual field impairments long after optic nerve damage (mean lesion age 5.5 years) were randomly assigned to a rtACS (n = 24) or sham stimulation group (n = 18). Visual fields and patient reported outcome measures (vision-related QoL: National Eye Institute Visual Function Questionnaire, NEI-VFQ and health-related QoL: Short Form Health Survey, SF-36) were collected before and after a 10-day treatment course with daily sessions of 20 to 40 minutes. The primary outcome measure was the percent change from baseline of detection ability (DA) in defective visual field sectors as defined by computer-based high resolution perimetry (HRP). Secondary outcome parameters included further HRP parameters as well as static and kinetic perimetry results. Changes in QoL measures were correlated with changes in primary and secondary outcome measures in both groups. RESULTS: DA increase in the defective visual field was significantly larger after rtACS (41.1 ± 78.9%, M ± SD) than after sham stimulation (13.6 ± 26.3%), P < 0.05. While there was a significant increase of DA in the whole tested HRP visual field after rtACS (26.8 ± 76.7%, P < 0.05), DA in sham-stimulation patients remained largely unchanged (2.7 ± 20.2%, ns). Results of secondary outcome measures (static and kinetic perimetry) provided further evidence of rtACS efficacy. Improvements in NEI-VFQ subscale "general vision" were observed in both groups but were larger in the rtACS group (11.3 ± 13.5, Z = -3.21, P < 0.001) than in the sham group (4.2 ± 9.4, Z = -1.73, P < 0.05) with a significant difference between groups (Z = -1.71, P < 0.05). DA change and some NEI-VFQ domains were correlated (r = 0.29, P < 0.05), but no significant correlations were observed between DA and SF-36 results. CONCLUSIONS: rtACS facilitates vision restoration after unilateral, long-term optic nerve lesion as assessed both by objective DA changes and improvements in some NEI-VFQ subscales. Both were positively but low correlated, which suggests that factors other than visual field size also contribute to improved vision-related QoL.

Cortical changes in complex regional pain syndrome (CRPS).

Recent research suggests that changes in cortical structures can contribute to the pathophysiology of Complex Regional Pain Syndrome (CRPS). This review provides an overview of studies showing cortical involvement in CRPS, including mislocalizations of tactile stimuli, changes in size and organization of the somatosensory map, changes in motor cortex representation and body perception disturbances. In addition, we review experimental treatment approaches, such as mirror therapy and motor imagery programs, aimed at restoring the integrity of neural processing in the sensory-motor cortex in individuals with CRPS. The intervention effects are promising and can be theoretically motivated on the basis of established principles of neural organization, although important questions concerning the precise neural mechanisms of action remain unanswered.

Functional electrical stimulation (FES) of the upper limb alleviates unilateral neglect: a case series analysis.

We report the results of a new form of therapy for unilateral spatial neglect. Functional electrical stimulation (FES) applied to the left forearm extensor muscles reduced the symptoms of severe left unilateral visual neglect in three patients, with the benefits being measurable at 6 months post-treatment. We suggest that FES activates a proprioceptive map within the right parietal lobe whose level of activation is otherwise diminished by the lesion. This both increases awareness of the contralesional side and stimulates functional interactions with the environment.

Improvement of visual scanning after DC brain polarization of parietal cortex in stroke patients with spatial neglect.

Previous studies have demonstrated that transcranial direct current (DC) brain polarization can modulate cortical excitability in the human brain. We investigated the effect of anodal DC brain polarization of right parietal cortex on visuospatial scanning in subacute stroke patients with spatial neglect. The patients underwent two neglect tests - figure cancellation and line bisection - before and immediately after anodal DC or sham in a double-blind protocol. Anodal DC was applied to the scalp over the right posterior parietal cortex (PPC) with an intensity of 2.0 mA for 20 min. Anodal DC brain polarization, but not sham, led to significant improvement in the both neglect tests. These results document a beneficial effect of DC brain polarization on neglect.

Impaired motor imagery in patients with essential tremor: a case control study.

Motor imagery (MI), which refers to the process of mental representation of movements, has not been studied in patients with essential tremor (ET). We investigated the presence of impaired MI in ET patients compared with healthy controls. A group of drug-naive and nondemented ET patients and age-matched controls were studied using transcranial magnetic stimulation, while they were specifically instructed to try and imagine themselves performing two motor tasks. The various clinical and electrophysiological variables were evaluated and compared. Repeated measures ANOVA demonstrated a significant difference between ET patients and controls with respect to mean motor-evoked potential (MEP) amplitudes (F(1,38) = 31.92, P < 0.005) during MI. The process of MI effectively facilitated MEP amplitude in controls but not in ET patients, regardless of side of stimulation or motor tasks. We provide evidence to demonstrate impairment of MI in a group of ET patients compared with healthy controls. The basis for this novel finding is unclear, and further studies are warranted to determine whether it is related to cerebellar or motor cortical dysfunction.

High-frequency rTMS improves time perception in Parkinson disease.

Patients with Parkinson disease (PD) are impaired in time processing. The authors investigated the effects of high-frequency (5 Hz) repetitive transcranial magnetic stimulation (rTMS) in patients with PD performing a time reproduction task. The authors found significant improvement in time processing induced by rTMS when trains were applied over the right dorsolateral prefrontal cortex (DLPFC) but not over the supplementary motor area, suggesting that the circuit involving the basal ganglia and the DLPFC might constitute the neural network subserving time perception.

Modulation and rehabilitation of spatial neglect by sensory stimulation.

After unilateral cortical or subcortical, often parieto-temporal lesions, patients exhibit a marked neglect of their contralateral space and/or body side. These patients are severely disabled in all daily activities, have a poor rehabilitation outcome and therefore require professional treatment. Unfortunately, effective treatments for neglect are just in the process of development. The present chapter reviews three aspects related to the rehabilitation of neglect. The first part summarizes findings about spontaneous recovery in patients and experimental animals with neglect. The second part deals with techniques and studies evaluating short-term sensory modulation effects in neglect. In contrast to many other neurological syndromes spatial neglect may be modulated transiently but dramatically in its severity by sensory (optokinetic, neck proprioceptive, vestibular, attentional, somatosensory-magnetic) stimulation. In part three, current treatment approaches are summarized, with a focus on three novel techniques: repetitive optokinetic stimulation, neck vibration training and peripheral somatosensory-magnetic stimulation. Recent studies of repetitive optokinetic as well as neck vibratory treatment both indicate significantly greater as well as multimodal improvements in neglect symptomatology as compared to the standard treatment of neglect. This clear superiority might result from the partial (re)activation of a distributed, multisensory vestibular network in the lesioned hemisphere. Somatosensory-magnetic stimulation of the neglected or extinguishing hand provides another feasible, non-invasive stimulation technique. It may be particularly suited for the rehabilitation of somatosensory extinction and unawareness of the contralesional body side. Finally, pharmacological approaches for the treatment of neglect are shortly addressed. Isolated drug treatment of neglect is currently no successful rehabilitation strategy due to inconsistent results as well as possible side effects. However, combined behavioural and drug treatments might yield better results. This has to be tested empirically in patient studies. In conclusion, the findings obtained in short-term sensory stimulation studies led to the development of effective techniques for the long-term rehabilitation of neglect. Future rehabilitation studies should evaluate effective treatment combinations considering all possible techniques and devices (behavioural, pharmacological, prosthetic or physiological).

Bottom-up transfer of sensory-motor plasticity to recovery of spatial cognition: visuomotor adaptation and spatial neglect.

A large proportion of right-hemisphere stroke patients show hemispatial neglect, a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space, inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment. This spatial cognition disorder affects the orientation of behavior with a shift of proprioceptive representations toward the lesion side. This shift is similar to that produced by psychophysical manipulations as a wedge-prism exposure in normal healthy subjects. In both subjects, one major compensative effect of short-term prism adaptation is a shift of proprioceptive representations, demonstrated by a shift in manual straight-ahead pointing in the dark, in a direction opposite to the visual shift. In neglect patients, prism adaptation involves the shift of proprioceptive representations to the left with a reduction of rightward bias observed in neglect patients in visuo-manual tasks as line-bisection, line-cancellation or copy drawing. Improvement of neglect is also observed in no visuo-manual tasks as mental imagery, auditory extinction or posture. This generalization of prism adaptation effects at different neglect level symptoms suggests that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations. Moreover the positive effects found for both sensorimotor and more cognitive spatial functions lasted for at least two or more hours after prism removal. Unlike reduction of neglect through sensory stimulations, the long-lasting improvement of neglect after prism adaptation suggests the activation of short-term plasticity of brain functions related to coordinate transformations and space representations. Lastly, the duration of these effects could be useful in rehabilitation programs, as suggested by the effects of prism adaptation on disabling neglect symptoms as wheelchair driving, posture or writing.

Modulation of spatial attention in a child with developmental unilateral neglect.

Attentional neglect of left space is one of the most striking acquired neurological disorders of adulthood. Recent evidence indicates a link between left spatial neglect and general right-hemisphere impairments in sustained attention and alertness. Poor sustained attention and alertness is also a central feature of other disorders, particularly childhood attention-deficit-hyperactivity disorder (ADHD). Here we present the case of a 7-year-old male showing that frank neglect can be present in children with sustained attention problems without a clear aetiological event, or obvious structural brain abnormalities as indicated by a normal MRI. Experimental amelioration of the neglect through left-hand movement and externally alerting stimulation by uninformative sounds further suggest close similarities to the adult disorder. We suggest that such distortions of spatial attention may be more common in childhood than previously thought.