Subjective body vertical: a promising diagnostic tool in idiopathic normal pressure hydrocephalus?

Rehabilitation effects in idiopathic normal pressure hydrocephalus: a randomized controlled trial

BACKGROUND

Gait-balance disturbances are core symptoms of idiopathic normal pressure hydrocephalus (iNPH). However, the rehabilitation effects of cerebrospinal fluid (CSF) shunting along with other treatment or no further treatment (natural course [NC]) for iNPH are unknown.

OBJECTIVES

This study evaluated whether dynamic equilibrium gait training (DEGT) can improve gait-balance functions after CSF shunting of patients with iNPH compared to standard exercise (SE) and NC. Furthermore, it investigated the incidence of falls.

METHODS

A total of 70 patients with iNPH who underwent CSF shunting were randomly assigned to 6 weeks of DEGT (n = 23), 6 weeks of SE (n = 23), or NC (n = 24). Evaluation was performed at baseline (preoperatively) and at 1 week, 7 weeks (postintervention), and 6 months postoperatively (follow-up). Outcomes were measured using the functional gait assessment (FGA), 10-m walk test, timed up-and-go test, life-space assessment (LSA), and fall incidence.

RESULTS

A total of 65 participants completed the study. During the intention-to-treat analysis, the DEGT group demonstrated significant recovery of gait-balance functions according to only the FGA at postintervention and follow-up compared to the SE and NC groups; however, recovery of the SE group did not differ from that of the NC group. The DEGT group had a significantly lower fall incidence than the other groups at follow-up. Significantly better LSA results were observed for all groups at follow-up compared to baseline; however, no difference in LSA results were observed between groups.

CONCLUSIONS

DEGT in addtion to CSF shunting can facilitate the recovery of gait-balance function and reduce the fall incidence of iNPH patients.

Perceived and actual changes in gait balance after CSF shunting in idiopathic normal pressure hydrocephalus

OBJECTIVES

We evaluated the perceived and actual changes in gait and balance function immediately after cerebrospinal fluid (CSF) shunting in patients with idiopathic normal pressure hydrocephalus (iNPH), including those with mild cases.

MATERIALS AND METHODS

Ninety-nine iNPH patients were assessed using the timed Up and Go (TUG) and Functional Gait Assessment (FGA) before and 1-week after CSF shunting and their perceived changes were assessed on a Global Rate of Change (GRC) scale. Minimal clinically important differences (MCIDs) were calculated using a receiver operating characteristic (ROC) curve method using GRC scores.

RESULTS

In all patients (n = 99), the TUG value postoperatively was significantly faster than the preoperative value (difference; 3.1 ± 4.6 s, p < 0.001), and the postoperative FGA score was significantly better than the preoperative score (difference; 3.8 ± 3.3 points, p < 0.001). In the TUG <15 s group (n = 51), the postoperative FGA score was significantly improved (difference; 3.3 ± 2.9 points, p < 0.001), whereas the TUG value was only slightly improved (difference; 0.6 ± 1.6 s, p = 0.008). The ROC curve MCIDs of GRC ≥2 points, which is the recommended level of improvement, were 1.7 s (16.5%) for the TUG and 4 points (20.0%) for the FGA in all patients (n = 99) and the TUG <15 s group (n = 51).

CONCLUSIONS

FGA can be used to confirm treatment effects, including perceived and actual changes after CSF shunting, in patients with mild iNPH. Our results can help clinicians to determine the clinical significance of improvements in gait and balance function immediately after CSF shunting in individual patients with iNPH.

The Scale for Retropulsion: Internal consistency, reliability and construct validity

BACKGROUND

Retropulsion is an impairment of body orientation against gravity in the sagittal plane. In a Delphi study, the Scale for Retropulsion (SRP) was developed with a high level of expert agreement.

OBJECTIVE

To assess the clinimetric properties of the German SRP in patients with neurological disorders.

METHODS

The SRP was applied to 70 hospitalized patients with neurological disorders (stroke, critical illness neuropathy and/or myopathy, Parkinson syndromes). Internal consistency was determined with the Cronbach ɑ. Test-retest and interrater reliabilities were evaluated with the weighted kappa, intraclass correlation coefficient (ICC), and Bland-Altman plots. The construct validity was evaluated with Spearman correlation.

RESULTS

The median (interquartile range) SRP score was 5 (3-8) and ranged from 0 to 22 (total scale range: 0 to 24). The SRP had excellent internal consistency (Cronbach ɑ = 0.875) and good to excellent test-retest reliability (weighted kappa = 0.957, ICC = 0.957) and interrater reliability (weighted kappa = 0.837, ICC = 0.837). Analysis of construct validity resulted in good correlations with other clinical balance scales (rSp > 0.80), and fair to moderate correlations with posturographic measures (rSp = 0.27-0.56) and the subjective postural vertical error in the sagittal plane (rSp = -0.325, p = 0.012) as well as the range in the frontal plane (rSp = 0.359, p=0.007). The SRP discriminated between patients classified with and without retropulsion by an independent clinical expert (p<0.001).

CONCLUSION

The SRP provides a valid and reliable bedside test to quantify retropulsion in individuals with neurological disorders.

New Mobile Device to Measure Verticality Perception: Results in Young Subjects with Headaches

The subjective visual vertical (SVV) test has been frequently used to measure vestibular contribution to the perception of verticality. Recently, mobile devices have been used to efficiently perform this measurement. The aim of this study was to analyze the perception of verticality in subjects with migraines and headaches. A cross-sectional study was conducted that included 28 patients with migraine, 74 with tension-type headache (TTH), and 93 healthy subjects. The SVV test was used through a new virtual reality system. The mean absolute error (MAE) of degrees deviation was also measured to qualify subjects as positive when it was greater than 2.5°. No differences in the prevalence of misperception in verticality was found among healthy subjects (31.18%), migraineurs (21.43%), or those with TTH (33.78%) (p = 0.480). The MAE was not significantly different between the three groups (migraine = 1.36°, TTH = 1.61°, and healthy = 1.68°) (F = 1.097, p = 0.336, and η2 = 0.011). The perception of verticality could not be explained by any variable usually related to headaches. No significant differences exist in the vestibular contribution to the perception of verticality between patients with headaches and healthy subjects. New tests measuring visual and somatosensory contribution should be used to analyze the link between the perception of verticality and headaches.

Misperception of Visual Verticality in Patients with Primary Headache Disorders: A Systematic Review with Meta-Analysis

Migraine and tension-type headache (TTH) are the two most prevalent primary headache disorders (PHDs) that may involve visual and vestibular impairments, neck pain, and postural unsteadiness. The perception of visual verticality (VV) has been studied in patients diagnosed with PHD to assess balance disorders showing varying findings. Our study aimed to assess the VV perception in patients diagnosed with PHD in comparison to healthy controls. A systematic review with meta-analysis was carried out in PubMed MEDLINE, Scopus, WOS, CINAHL, and SciELO. The Cohen standardized mean difference (SMD) was used to estimate the differences between exposed and healthy controls. Seven studies with 816 participants were included. The quality of included studies, according to the Newcastle–Ottawa Scale (NOS), was moderate (mean score of 5.2). Patients diagnosed with PHD showed a moderate misperception of VV as assessed with the subjective visual vertical (SVV) test (SMD = 0.530; 95% CI = 0.225, 0.836; p < 0.001). Specifically, a misperception of the SVV was found in patients with migraine (SMD = 0.369; 95% CI = 0.1, 0.638; p = 0.007) and with TTH (SMD = 1.122; 95% CI = 0.540, 1.704; p < 0.001). This review shows a misperception of VV in patients with migraine and TTH when assessed with the SVV test, being higher in patients with TTH, although the THH sample size was low.

Associations among falls, gait variability, and balance function in idiopathic normal pressure hydrocephalus

OBJECTIVES

The factors influencing falls in idiopathic normal pressure hydrocephalus (iNPH) remain unclear, although iNPH-associated gait and balance disturbances can lead to an increased risk of falls. This study aimed to investigate the associations among fall status, gait variability, balance function in iNPH, and to identify fall-related factors in iNPH.

PATIENTS AND METHODS

Sixty-three patients with iNPH with a positive cerebrospinal fluid tap test result according to the iNPH diagnosis criteria participated in this prospective cross-sectional study. Patients were assessed using the 10-meter walk test (10MWT), the Functional Gait Assessment (FGA), the Berg Balance Scale (BBS), and the isometric quadriceps strength (QS). We also investigated each patient's history of falls in the past 6 months. Gait variability was measured using a triaxial accelerometer attached to the patient's torso at the L3 vertebra level during the 10MWT.

RESULTS

Fall status correlated significantly with gait variability (measured as the coefficient of variation; CV) in step time and movement trajectory amplitude (i.e., center of mass movement) in the medial/lateral (ML) and vertical (VT) directions, with balance function as assessed by FGA and BBS scores. In contrast, QS was not correlated with fall status. The independent variables associated with the risk of falling were step time CV, FGA score, and age.

CONCLUSION

The factors associated with the risk of falling in iNPH were aging and gait-balance instability, particularly temporal gait variability and dynamic balance dysfunction. Our results may enable physicians to identify the patients with iNPH who are at risk of falling and implement suitable prevention strategies.

Perception of Verticality and Vestibular Disorders of Balance and Falls

Objective: To review current knowledge of the perception of verticality, its normal function and disorders. This is based on an integrative graviceptive input from the vertical semicircular canals and the otolith organs.

Methods: The special focus is on human psychophysics, neurophysiological and imaging data on the adjustments of subjective visual vertical (SVV) and the subjective postural vertical. Furthermore, examples of mathematical modeling of specific vestibular cell functions for orientation in space in rodents and in patients are briefly presented.

Results: Pathological tilts of the SVV in the roll plane are most sensitive and frequent clinical vestibular signs of unilateral lesions extending from the labyrinths via the brainstem and thalamus to the parieto-insular vestibular cortex. Due to crossings of ascending graviceptive fibers, peripheral vestibular and pontomedullary lesions cause ipsilateral tilts of the SVV; ponto-mesencephalic lesions cause contralateral tilts. In contrast, SVV tilts, which are measured in unilateral vestibular lesions at thalamic and cortical levels, have two different characteristic features: (i) they may be ipsi- or contralateral, and (ii) they are smaller than those found in lower brainstem or peripheral lesions. Motor signs such as head tilt and body lateropulsion, components of ocular tilt reaction, are typical for vestibular lesions of the peripheral vestibular organ and the pontomedullary brainstem (vestibular nucleus). They are less frequent in midbrain lesions (interstitial nucleus of Cajal) and rare in cortical lesions. Isolated body lateropulsion is chiefly found in caudal lateral medullary brainstem lesions. Vestibular function in the roll plane and its disorders can be mathematically modeled by an attractor model of angular head velocity cell and head direction cell function. Disorders manifesting with misperception of the body vertical are the pusher syndrome, the progressive supranuclear palsy, or the normal pressure hydrocephalus; they may affect roll and/or pitch plane.

Conclusion: Clinical determinations of the SVV are easy and reliable. They indicate acute unilateral vestibular dysfunctions, the causative lesion of which extends from labyrinth to cortex. They allow precise topographical diagnosis of side and level in unilateral brainstem or peripheral vestibular disorders. SVV tilts may coincide with or differ from the perception of body vertical, e.g., in isolated body lateropulsion.

The effect of CSF drainage on ambulatory center of mass movement in idiopathic normal pressure hydrocephalus

BACKGROUND

Although gait and balance disturbances are core symptoms of idiopathic normal pressure hydrocephalus (iNPH), the ambulatory center of mass (COM) movements in patients with iNPH remain unclear. We aimed to clarify the ambulatory COM movements using an accelerometer on the patients' lower torsos and to investigate the changes in COM movement after cerebrospinal fluid tap tests (TT) and shunt surgeries (SS).

METHODS

Twenty-three patients with iNPH and 18 age-matched healthy controls (HCs) were recruited. A triaxial accelerometer was fixed with a belt onto each participant's torso at the L3 vertebra level. We assessed each patient's 10-m gait before TT, 3 days after TT, and 1 week after SS.

RESULTS

Compared to the HCs, the patients exhibited decreased gait velocities, increased step numbers, and increased step times. Their movement trajectory amplitudes (i.e., the COM movements) were increased in the medial/lateral direction and decreased in the vertical direction. They also exhibited greater variability (measured as coefficients of variation) in step time and movement trajectory amplitude in both the medial/lateral and vertical directions. The patients' gait parameters were significantly improved after TT and SS.

SIGNIFICANCE

Our results suggest that iNPH-associated gait disturbances could cause abnormal ambulatory COM movements and that these disturbances are mitigated by TT and SS.