Does Catastrophizing Predict Response to Treatment in Patients With Vestibular Disorders? A Prospective Cohort Study

OBJECTIVE

Determine levels of catastrophizing in patients with vestibular disorders and prospectively evaluate their relationship with patient-reported outcome measures.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary care neurotology vestibular disorders clinic.

PATIENTS

Adult patients with various vestibular disorders.

INTERVENTIONS

Patients were given the Dizziness Handicap Inventory (DHI) and the Dizziness Catastrophizing Scale (DCS) at a baseline visit and follow-up visit after treatment.

MAIN OUTCOME MEASURES

Correlation studies were used to determine the relationships between DHI and DCS. Multivariable linear regression was performed to determine the relationship between DCS and DHI change with treatment, accounting for demographic variables.

RESULTS

Forty-six subjects completed both the DHI and the DCS before and after treatment. Patients with higher baseline DCS scores had higher baseline DHI scores ( p < 0.001). There was a significant improvement in both DHI score ( p < 0.001) and DCS ( p < 0.001) at follow-up. Patients who had reduction in DCS scores during were more likely to show reduction in DHI scores ( p < 0.001). A subset of patients had a mindfulness-based stress reduction program included in their treatment. These patients had a greater reduction in both DCS and DHI scores at follow-up compared with those who received other treatments.

CONCLUSIONS

Catastrophizing is associated with higher pretreatment DHI scores and worse treatment outcomes. Addressing dizziness catastrophizing may help improve vestibular outcomes.

Recent Developments in Vestibular Migraine: A Narrative Review

PURPOSE

The aim of this study was to review current literature regarding the epidemiology of vestibular migraine (VM), patient presentation, pathogenesis, and treatment.

RECENT FINDINGS

VM is becoming an increasingly recognized condition in the United States, currently affecting 2.7% of people. Patients may experience vestibular symptoms, such as vertigo and imbalance, with or without other migrainous symptoms. Recent evidence has also shown that patients with VM are at higher risk for cochlear dysfunction, such as sudden deafness, sensorineural hearing loss, and tinnitus. The heritability and genetics are not well understood, and the pathogenesis may involve calcitonin gene-related peptide, which is also implicated in migraine headaches. A disease-specific patient reported outcome measure, the Vestibular Migraine Patient Assessment Tool and Handicap Inventory, was recently developed and validated. A limited number of controlled trials have assessed various therapies for VM, including triptans and beta-blockers. More data are needed to understand whether or not currently available migraine treatments are effective for VM.

SUMMARY

VM is a common etiology of vertigo and dizziness, presenting with a characteristic spectrum of symptoms. Early data suggest that migraine treatments may be helpful in some cases.

VM-PATHI Correlates With Cognitive Function Improvement After Successful Treatment in Patients With Vestibular Migraine

OBJECTIVE

To assess changes in cognitive function in vestibular migraine patients undergoing treatment.

STUDY DESIGN

Prospective cohort.

SETTING

Single-institution tertiary-care center.

PATIENTS

Thirty-four patients with vestibular migraine were included in the study. Average age at diagnosis was 47.9 years. A majority of patients (91.2%) were female.

INTERVENTIONS

Vestibular therapies included pharmacologic treatment (67.6%), mindfulness-based stress reduction (58.8%), vestibular physical therapy (20.6%), and lifestyle changes only (2.9%).

MAIN OUTCOME MEASURES

Pretreatment and posttreatment questionnaires were collected including the Cognitive Failures Questionnaire (CFQ), Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI), and Dizziness Handicap Inventory.

RESULTS

Median time between pretreatment and posttreatment questionnaire was 4.4 months (range, 2.8-15.6. mo). CFQ scores decreased in subjects who responded to treatment, as defined by those with a positive change in VM-PATHI score (average decrease, 6.5; p = 0.03). CFQ scores did not improve in subjects who had no improvement in their vestibular condition, as defined by no change or an increase in VM-PATHI score (average increase, 2.0; p = 0.53). Univariate linear regression showed that VM-PATHI score change was highly predictive of CFQ change ( p < 0.01, r2 = 0.36). Multivariate regression demonstrated that the VM-PATHI ( p = 0.03) and not the Dizziness Handicap Inventory ( p = 0.10) predicted changes in CFQ score.

CONCLUSIONS

Self-reported cognitive dysfunction improves with successful treatment of vestibular migraine.

Visually enhanced vestibulo-ocular reflex gain in patients with vestibular disease

Objective

Vestibular migraine (VM) is a diagnostic challenge. Visually enhanced vestibulo-ocular reflex (VVOR) gain, a measure of the visual-vestibular interaction, has been proposed as a tool for diagnosing VM. This study seeks to evaluate VVOR gain's diagnostic capability to predict VM and to compare the phenotypes of vestibular patients with elevated versus normal/low VVOR gain.

Methods

A retrospective review of consecutive adult patients at a dizziness clinic from October 2016 and December 2020 was conducted. VVOR gain's diagnostic performance was assessed with the area under the receiver operating characteristic (AUROC) analysis. Demographic factors and clinical presentations were compared between vestibular patients with elevated versus normal/low VVOR gain.

Results

One hundred forty patients (70 with VM) were analyzed. VVOR gain was elevated in 68.6% of patients with VM, compared to 52.9% of patients without VM (p = .057). The AUROC of VVOR gain was 0.5902 (95% confidence interval: 0.4958-0.6846). Vestibular patients with elevated VVOR gain were younger than those with normal/low VVOR gain (mean age 50 vs. 62, p < .0001). A higher proportion of subjects with elevated VVOR gain had symptoms triggered by certain foods (17.6% vs. 5.5%, p = .040) and experienced sound sensitivity (34.1% vs. 18.2%, p = .040) and motion sensitivity (23.5% vs. 9.1%, p = .041). A greater proportion of VM patients with elevated VVOR gain were triggered by certain foods (27.1% vs. 0%, p = .006).

Conclusion

VVOR gain alone has limited ability to discriminate VM from other vestibular conditions and must be interpreted carefully. VVOR gain elevation may be associated with food triggers and motion and sound sensitivity.

Level of Evidence

IV.

Evaluation of motor cortical excitability using evoked torque responses: A new tool with high reliability

BACKGROUND

Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) are typically recorded via surface electromyography (EMG). However, another suitable alternative may be recording torque output associated with MEPs, especially when studying multiheaded muscles (e.g. quadriceps) for which EMG may not be ideal.

METHODS

We recorded the motor evoked torque elicited by TMS along with conventional EMG-based MEPs (MEP_EMG) over a range of TMS intensities (100-140 % of active motor threshold [AMT]) from twenty healthy young adults on two different days. MEPs were normalized using different normalization procedures (raw, normalized to maximum voluntary isometric contraction [MVIC], and peak MEP). Additionally, motor evoked torque was normalized to TMS-evoked peripheral resting twitch torque. Intraclass correlation coefficients (ICCs) were determined for each of these variables to compute reliability.

RESULTS

Motor evoked torque showed good to excellent reliability (ICC: 0.65-0.90) at TMS intensities ≥ 110 % AMT, except when normalized by peak MEP. The reliability of raw MEP_EMG and MVIC normalized MEP_EMG was fair to excellent only at ≥ 130 % AMT (ICC: 0.42-0.82) and at ≥ 120 % AMT (ICC: 0.41-0.83), respectively. The reliability of both MEP_EMG and motor evoked torque generally increased with increasing TMS intensities, with motor evoked torque normalized to the resting twitch torque yielding the best ICC scores.

COMPARISON WITH EXISTING METHODS

When compared with conventional MEP_EMG, motor evoked torque offers superior and reliable estimates of corticospinal excitability, particularly when normalized to resting twitch torque.

CONCLUSIONS

TMS-induced motor evoked torque can reliably be used to measure corticospinal excitability in the quadriceps muscles.

Immunoglobulin G subclass distribution in three human intravenous immunoglobulin preparations

In immunodeficiency patients the lack of immunoglobulins (Ig) can be total or partial with a specific IgG subclass imbalance masked by normal values for total IgG. In the latter case therapy with intravenous IgG preparations (IVIG) is generally beneficial, provided the IVIG preparations used originate from large pools of normal blood donors and exhibit a normal IgG subclass distribution. We have analyzed the subclass distribution of three IVIG products: Sandoglobulin (SAGL), GamimuneN (GI), Gammagard (GG), 6-10 lots each, in four different laboratories. The competitive enzyme immunoassays and radial immunodiffusion methods used different monoclonal and polyclonal antibodies specific for IgG1, IgG2, IgG3, and IgG4, respectively. Despite minor interlaboratory differences, the results show that the slightly lower IgG1 content of SAGL versus GI and GG was quantitatively compensated by a higher proportion of IgG2, that no differences existed in IgG3 levels, but that one preparation (SAGL) contained 2-3% of IgG4 compared to 0.5-1.5% in GI and below 0.5% in GG. This difference was significant, the two latter preparations being at or below the lower limit of what are considered to be normal values found in human adults. Such differences may have important clinical consequences.

Differences among available immunoglobulin preparations for intravenous use

Today almost all IgG preparations for intravenous use (IVIG) fulfill the basic requirements for a preparation given intravenously (sterility, pyrogenicity, antibody content but also anticomplementary activity, etc.). However, there are still marked differences among such preparations caused by the method of preparation: (1) Enzymatically treated IVIGs (by pepsin and plasmin) have a shorter biologic half-time and a disturbed IgG subclass composition; (2) in chemically treated IVIGs (beta-propiolactone, reduced or sulfonated IgGs) the IgG3 subclass is lacking and some of the Fc-related functions are altered; and (3) the IVIGs purified by anion exchangers are poor in the IgG4 subclass. The three main preparations sold in the United States (Gamimune N, Gammagard and Sandoglobulin) belong to the nonmodified preparations and, with the exception of the IgG subclass representation, show similar Fab- and Fc-related properties (antibody content, interaction with Fc receptors on monocytes, phagocytosis-promoting activity, etc.) In none of these preparations, an elevated level of undesired contaminants (prekallikrein activator, irregular anti-erythrocyte antibodies) are found.

Opsonic and physicochemical characteristics of intravenous immunoglobulin preparations

The composition and opsonizing activity of five commercially available immunoglobulin preparations for intravenous use (Venoglobulin I, Venilon, Gammagard, Polyglobin, and Sandoglobulin) were studied. The composition of these preparations does not differ very much as far as total protein, immunoglobulin class and IgG subclass concentrations are concerned. The only exceptions were that Veniglobulin I, Gammagard and Sandoglobulin contain IgA, which might cause side effects in patients with anti-IgA antibodies, Gammagard contains very little IgG4, and Venilon and Polyglobin contain no and almost no IgG3, respectively, which might explain their very low opsonic activity. It was found that Venilon and Gammagard activate complement in the ready-for-infusion state. The opsonic activity of Venoglobulin I, Sandoglobulin and Gammagard is about equal to that of inactivated serum: Staphylococcus aureus, Escherichia coli with K antigen, Streptococcus pyogenes and Streptococcus group B are well opsonized and E. coli without K antigen and Streptococcus pneumoniae are poorly opsonized.

Quality control in the production of an immunoglobulin for intravenous use

This paper briefly surveys the control measures and tests which are carried out before, during and after manufacture of an i.v. immunoglobulin in order to assure the quality of the preparation. The quality requirements are determined by both the standards expected by physicians and patients and by the specifications of the registration authorities in the various countries. A great deal of know-how and considerable technical investment is required to match these requirements. Furthermore a comprehensive quality assurance programme is compulsory: It begins with the careful collection and analysis of each single blood donation, continues through all the manufacturing stages and ends with the rigorous testing of every batch of the end product - an examination comprising 23 different tests.