Gerd Fabian Volk

Modern concepts in facial nerve reconstruction

BackgroundReconstructive surgery of the facial nerve is not daily routine for most head and neck surgeons. The published experience on strategies to ensure optimal functional results for the patients are based on small case series with a large variety of surgical techniques. On this background it is worthwhile to develop a standardized approach for diagnosis and treatment of patients asking for facial rehabilitation.ConclusionA standardized approach is feasible: Patients with chronic facial palsy first need an exact classification of the palsys aetiology. A step-by-step clinical examination, if necessary MRI imaging and electromyographic examination allow a classification of the palsys aetiology as well as the determination of the severity of the palsy and the functional deficits. Considering the patients desire, age and life expectancy, an individual surgical concept is applicable using three main approaches: a) early extratemporal reconstruction, b) early reconstruction of proximal lesions if extratemporal reconstruction is not possible, c) late reconstruction or in cases of congenital palsy. Twelve to 24 months after the last step of surgical reconstruction a standardized evaluation of the therapeutic results is recommended to evaluate the necessity for adjuvant surgical procedures or other adjuvant procedures, e.g. botulinum toxin application. Up to now controlled trials on the value of physiotherapy and other adjuvant measures are missing to give recommendation for optimal application of adjuvant therapies.

Decreased Olfactory Bulb Volume in Idiopathic Parkinson's Disease Detected by 3.0-Tesla Magnetic Resonance Imaging

A number of neuropathological studies have demonstrated that the olfactory system is among the first brain regions affected in Parkinsons disease (PD). These findings correlate with pathophysiological and pathological data that show a loss in olfactory bulb (OB) volume in patients with PD. However, to date, MRI has not been a reliable method for the in vivo detection of this volumetric loss in PD. Using a 3.0‐Tesla MRI constructive interference in the steady‐state sequence, OB volume was evaluated in patients with PD (n = 16) and healthy control subjects (n = 16). A significant loss of OB volume was observed in patients with PD, compared to the healthy control group (91.2 ± 15.72 versus 131.4 ± 24.56 mm3, respectively). Specifically, decreased height of the left OB appears to be a reliable parameter that is adaptable to clinical practice and significantly correlates with OB volume loss in patients with idiopathic PD. Measuring both the volume and height of the OB by MRI may be a valuable method for the clinical investigation of PD.

Cortical reorganization in Bell's palsy

PURPOSE Bells palsy, a unilateral, idiopathic facial nerve palsy, is a common disorder that is generally followed by a good recovery of function. The aim of this study was to investigate the impact of such a transiently decreased motor control (without deafferentation) on the functional reorganization of the brain. METHODS To address this issue, functional MRI was applied to 10 patients in the acute state of Bells palsy and after their complete clinical recovery. The functional paradigm consisted of unilateral facial movements with the affected as well as the non-affected side. RESULTS We found an overactivity of several brain areas contralateral to the palsy that are related to error detection and sensory-motor integration in the acute stage and motor integration and control in the follow-up. Functional connectivity was disrupted in the affected cortical motor system during the acute stage of Bells palsy compared to the follow-up. This altered connectivity was found mostly between motor areas in the hemisphere contralateral to the paretic side, whereas the interhemispherical connectivity remained largely stable. CONCLUSION Our results indicate that a transient peripheral deefferentation causes functional reorganization in the brain that partly persists even after an apparently complete clinical recovery.

Prognostication of recovery time after acute peripheral facial palsy: a prospective cohort study

Objective Owing to a lack of prospective studies, our aim was to evaluate diagnostic factors, in particular, motor and non-motor function tests, for prognostication of recovery time in patients with acute facial palsy (AFP). Design Prospective cohort study. Setting University hospital. Participants 259 patients with AFP. Measurements Clinical data, facial grading, electrophysiological motor function tests and other non-motor function tests were assessed for their contribution to recovery time. Results The predominant origin of AFP was idiopathic (59%) and traumatic (21%). At baseline, the House-Brackmann scale (HB) was >III in 46% of patients. Follow-up time was 5.6±9.8 months with a complete recovery rate of 49%. The median recovery time was 3.5 months (95% CI 2.2 to 4.7 months). The following variables were associated with faster recovery: Interval between onset of AFP and treatment <6 days versus ≥6 days (median recovery time in months 2.1 vs 6.5; p<0.0001); HB ≤III vs >III (2.2 vs 4.6; p=0.001); no versus presence of pathological spontaneous activity in first electromyography (EMG; 2.8 vs probability of recovery <50%; p<0.0001); no versus voluntary activity in EMG (probability of recovery <50% vs 3.1; p<0.0001); normal versus pathological ipsilateral electroneurography (1.9 vs 6.5; p=0.008), normal versus pathological stapedius reflexes (1.6 vs 3.3; p=0.003). Conclusions Start of treatment and grading, but most importantly EMG evaluated for pathological spontaneous activity and the stapedius reflex test are powerful prognosticators for estimating the recovery time from AFP. These results need confirmation in larger datasets.

Time Course of Cortical Plasticity After Facial Nerve Palsy A Single-Case Study

Background. Functional connectivity is defined as the temporal correlation between spatially remote neurophysiological events. This method has become particularly useful for studying neuroplasticity to detect changes in the collaboration of brain areas during cortical reorganization. Methods. In this article, the authors longitudinally studied voxel-based morphometry and resting state functional magnetic resonance imaging 10 times in 1 patient during the course of Bell palsy (idiopathic facial nerve palsy) up to complete clinical recovery. Results. Morphometric analysis revealed a significant alteration in the face area of the primary motor cortex (M1) contralateral to the paretic face, with an initial increase in gray matter concentration. Functional connectivity analysis between the M1 and other parts of the facial motor network revealed acutely disrupted intrahemispheric connectivity but unaltered interhemispheric connectivity. The disrupted functional connectivity was most pronounced on the day of the onset of symptoms, with a subsequent return toward normal during the course of recovery. This time course was found to differ between the selected parts of the facial motor network. However, the increase in functional connectivity strength preceded clinical recovery in all areas and reached a stable level before the patient fully recovered. Conclusion. These results demonstrate that recovery from facial nerve palsy is complemented by cortical reorganization, with pronounced changes of functional connectivity that precede clinical recovery.

Quantitative ultrasonography of facial muscles in patients with chronic facial palsy

Introduction: In this study we introduce quantitative facial muscle ultrasound as a diagnostic tool for patients with chronic unilateral facial palsy. Methods: Muscle area, thickness, and echo intensity of 6 facial muscles (frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis) and of 2 chewing muscles (temporalis and masseter, as controls) were measured in 20 patients with chronic facial palsy. Results: Aside from 1, all facial muscles were significantly smaller on the paralyzed side. With exception of frontalis and orbicularis oculi muscles, all other facial muscles showed significantly higher echo intensity on the affected side. Muscle size and echo intensity of the chewing muscles showed no side‐to‐side asymmetry. Conclusions: Quantitative ultrasound of facial muscles helps to better characterize their status in patients with chronic facial palsy in the phase of denervation and during regeneration. Muscle Nerve 50: 358–365, 2014

Quantitative ultrasonography of facial muscles

Introduction: There is no standardized method for examination of facial muscles with ultrasound. The purpose of this study was to identify those facial muscles accessible for reliable identification and to provide reference data. Methods: In healthy subjects all facial muscles were screened for visibility, separation from adjacent muscles, and reliability of landmarks. Bilateral scans of reliable muscles were performed in 40 adult volunteers. Results: Six facial muscles were clearly demarcated with ultrasound. These were: frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis muscles. Cross‐sectional area and muscle thickness showed gender differences and were independently related to age for some muscles. A significant left–right side difference was only seen for the orbicularis oculi muscle in women. Conclusions: These data demonstrate the usefulness of ultrasonography to assess facial muscles and provide reference values that can be applied in the clinical setting. Muscle Nerve 47: 878–883, 2013

Facial Disability Index und Facial Clinimetric Evaluation Skala: Validierung der deutschen Versionen

BACKGROUND A validated instrument to measure patient-related outcome and quality of life in facial palsy is not available in German language. METHODS 2 appropriate questionnaires, the Facial Clinimetric Evaluation (FaCE) scale and the Facial Disability Index (FDI) were translated and validated according to international guidelines. The internal consistency of both German versions was assessed. The results of FaCE and FDI were correlated with results of the SF-36, the House-Brackmann scale and the Stennert index. RESULTS 122 facial palsy patients with a median duration of 4.7 months were included. FaCE and FDI showed good to very good psychometric characteristics with Cronbachs alpha values between 0.667 and 0.907. Both questionnaires were able to distinguish different degrees of facial palsy. The comparison to the SF-36 shows the highest correlation with the subscale social function. DISCUSSION The German versions of the FDI and FaCE are valid and should now be applied more frequently to assess the disease-specific quality of life in patients with facial palsy.

Components of vestibular cortical function.

It is known that the functional response (e.g., nystagmus) to caloric vestibular stimulation is delayed and prolonged compared with the stimulus-response timing of other sensory systems. Imaging studies have used different models to predict cortical responses and to determine the areas of the brain that are involved. These studies have revealed a widespread network of vestibular brain regions. However, there is some disagreement regarding the brain areas involved, which may partly be caused by differences in the models used. This disagreement indicates the possible existence of multiple cortical components with different temporal characteristics that underlie cortical vestibular processing. However, data-driven methods have yet to be used to analyze the underlying hemodynamic components during and after vestibular stimulation. We performed functional magnetic resonance imaging (fMRI) on 12 healthy subjects during caloric stimulation and analyzed these data using a model-free analysis method (ICA). We found seven independent stimulus-induced components that outline a robust pattern of cortical activation and deactivation. These independent components demonstrated significant differences in their time courses. No single-modeled response function was able to cover the entire range of these independent components. The response functions determined in the present study should improve model-based studies investigating vestibular cortical processing.

Reference values for dynamic facial muscle ultrasonography in adults

Introduction: Ultrasonography can detect structural muscle changes caused by neuromuscular disease, but it has not yet been applied to facial nerve diseases. Quantitative analysis would be the preferred method to determine whether ultrasound findings are within normal limits, but there are no normative data for mimic muscles. The purpose of this study was to provide gender‐specific normative ultrasonography data for muscle area, diameter, and contractility for mimic and masticatory muscles in adults. Methods: Bilateral scans of multiple mimic and masticatory muscles were performed at rest and during contraction in 140 volunteers, aged 21–93 years. Results: Almost all mimic muscles, but not the temporalis muscles, had symmetric size. The muscle sizes showed gender differences and a muscle‐specific correlation with body weight, but not with age. Conclusions: These data provide normative values that can be used in clinical practice. Muscle Nerve 50: 348–357, 2014