Purpose To model tension asymmetry caused by superior laryngeal nerve paralysis (SLNP) in excised larynges and apply perturbation, nonlinear dynamic, and aerodynamic analyses. Method SLNP was modeled in 8 excised larynges using sutures and weights to mimic cricothyroid (CT) muscle function. Weights were removed from one side to create tension asymmetry, mimicking unilateral SLNP. Two sets of weights were used, 1 light and 1 heavy. Five conditions were evaluated: (a) no tension, (b) symmetrical light tension, (c) asymmetrical light tension, (d) symmetrical heavy tension, and (e) asymmetrical heavy tension. Results Perturbation parameters were not significantly different across conditions: percent jitter, χ 2 (4) = 3.70, p = .451; percent shimmer, F (4) = 0.95, p = .321. In addition, many measurements were invalid (error values >10). Second-order entropy was significantly different across conditions, F (4) = 5.432, p = .002, whereas correlation dimension was not, F (4) = 0.99, p = .428. Validity of these nonlinear dynamic parameters was demonstrated by low standard deviations. Phonation threshold pressure, χ 2 (4) = 22.50, p < .001, and power, χ 2 (4) = 9.50, p = .05, differed significantly across conditions, whereas phonation threshold flow did not, χ 2 (4) = 4.08, p = .396. Conclusions Nonlinear dynamic analysis differentiated between symmetrical and asymmetrical tension conditions, whereas traditional perturbation analysis was less useful in characterizing type 2 or 3 vocal signals. Supplementing acoustic with aerodynamic parameters may help distinguish among laryngeal disorders of neuromuscular origin.
Abstract Background Parkinson's disease ( PD ) can cause severe dysphagia, especially later in disease progression. Early identification of swallowing dysfunction may lead to earlier intervention. Pharyngeal high‐resolution manometry ( HRM ) provides complementary information to videofluoroscopy, with advantages of being quantitative and objective. Artificial neural network ( ANN ) classification can examine non‐linear relationships among multiple variables with relatively low bias. We evaluated if ANN techniques could differentiate between patients with PD and healthy controls. Methods Simultaneous videofluoroscopy and pharyngeal HRM were performed on 31 patients with early to mid‐stage PD and 31 age‐ and sex‐matched controls during thin‐liquid swallows of 2 cc, 10 cc and comfortable sip volume. We performed multilayer‐perceptron analyses on only videofluoroscopic data, only HRM data or a combination of the two. We also evaluated variability‐based parameters, representing variability in manometric parameters across multiple swallows. We hypothesized that patients with PD and controls would be classified with at least 80% accuracy, and that combined videofluoroscopic and HRM data would classify participants better than either alone. Key Results Classification rates were highest with all parameters considered. Maximum classification rate was 82.3 ± 5.2%, recorded for 2 cc swallows. Inclusion of variability‐based parameters improved classification rates. Classification rates using only manometric parameters were similar to those using all parameters, and rates were substantially lower for the comfortable sip volumes. Conclusions & Inferences Results from these classifications highlight the differences between swallowing function in patients with early and mid‐stage PD and healthy controls. Early identification of swallowing dysfunction is key to developing preventative swallowing treatments for those with PD .
Abstract Age-related decline in functional reserve has been described in tongue strength: tongue pressure during swallowing does not change with age, but maximal-effort isometric tongue pressure decreases with age. Healthy persons show a slight increase in pharyngeal swallowing pressure with age, but it is unknown if there is a similar decline in functional reserve. Fifty-six healthy adults (n=38 60 years) underwent pharyngeal high-resolution manometry during effortful and normal-effort thin liquid swallows. Repeated measures ANOVAs were performed on maximum pressures, pharyngeal contractile integral (PCI), pharyngeal pressure gradients, and upper esophageal sphincter minimum pressures. We hypothesized that older individuals would generate a less-robust pressure increase with effortful swallowing than younger individuals. Maximum pressures, PCI, and gradients increase during effortful swallowing (p<0.001), but there was no interaction effect with age, suggesting a lack of age-related functional reserve decline. Older individuals had greater UES minimum pressures than younger individuals in the effortful swallowing task (p=0.03), which may stem from reduced muscular compliance in this area. These findings do not align with those reported in tongue pressures, suggesting that muscle properties and pressure generation may be fundamentally different between the pharynx and the oral tongue. Alternatively, the effortful swallowing task may not elicit maximum contractility of the pharyngeal musculature. The preserved ability to increase pharyngeal pressure during effortful swallowing may support the use of the effortful swallow exercise in older adults with swallowing disorders.
The swallowing muscles that influence upper esophageal sphincter (UES) opening are centrally controlled and modulated by sensory information. Activation and deactivation of neural inputs to these muscles, including the intrinsic cricopharyngeus (CP) and extrinsic submental (SM) muscles, results in their mechanical activation or deactivation, which changes the diameter of the lumen, alters the intraluminal pressure, and ultimately reduces or promotes flow of content. By measuring the changes in diameter, using intraluminal impedance, and the concurrent changes in intraluminal pressure, it is possible to determine when the muscles are passively or actively relaxing or contracting. From these "mechanical states" of the muscle, the neural inputs driving the specific motor behaviors of the UES can be inferred. In this study we compared predictions of UES mechanical states directly with the activity measured by electromyography (EMG). In eight subjects, pharyngeal pressure and impedance were recorded in parallel with CP- and SM-EMG activity. UES pressure and impedance swallow profiles correlated with the CP-EMG and SM-EMG recordings, respectively. Eight UES muscle states were determined by using the gradient of pressure and impedance with respect to time. Guided by the level and gradient change of EMG activity, mechanical states successfully predicted the activity of the CP muscle and SM muscle independently. Mechanical state predictions revealed patterns consistent with the known neural inputs activating the different muscles during swallowing. Derivation of "activation state" maps may allow better physiological and pathophysiological interpretations of UES function.
Historic methods of classifying temporal bone fractures have been shown to poorly correlate with clinical findings. Due to the mechanisms of injury associated with these fractures, complete examination of patients can be difficult. An effective and simple way of correlating radiological findings in temporal bone fractures with complications like facial nerve weakness and paralysis will better guide physicians in treatment of their patients. We hypothesize that a classification system based on the medial extent of a fracture will best predict facial nerve injuries.
Study Design and Methods
A retrospective chart review identified 109 patients with 131 temporal bone fractures. Temporal bone CT scans and a record of facial nerve evaluation was available in 115 fractures (99 patients). CT scans were reviewed and fractures were classified by our proposed system and by the traditional system (longitudinal, transverse, and mixed). Our proposed system is as follows: Group A is a lateral fracture involving the mastoid, external auditory canal, and/or temporomandibular joint; Group B involves the tympanic cleft; Group C involves the course of the facial nerve; and Group D involves the otic capsule. A final rating of A-D was given based on the medial most extent of the fracture line. Fractures were grouped according to the classification schemes and correlated with clinical reports of facial nerve dysfunction.
Results
In 115 temporal bone fractures, 16 patients with facial nerve weakness or paralysis were identified. Using the new classification scheme, facial nerve injury was present as follows: Group A fractures - 0/20, Group B - 5/55 (9%), Group C - 6/31 (19%), Group D - 5/9 (56%). Using the traditional classification system, facial nerve dysfunction was present as follows: 11/72 (13%) of longitudinal fractures, 4/21 (19%) of transverse fractures, and 3/22 (14%) of mixed fractures.
Conclusion
When compared to the traditional classification system for temporal bone fractures, these results demonstrate that the new system appears to have a higher predictive value with facial nerve function. This simple system can help physicians to triage patients and guide treatment even if a complete examination of the patient is not possible.
Lymph node yield in therapeutic neck dissection is clinically significant and incompletely studied. We quantified node yield based on extent of neck dissection and presence of preoperative radiation. We also evaluated factors affecting incidence of extracapsular spread (ECS).Retrospective review of 499 patients undergoing therapeutic neck dissection; 414 patients met inclusion criteria and were divided into 2 groups: neck dissection alone or before radiation (surgery first: 280 patients; 385 dissections) and primary radiation before surgery (radiation first: 134 patients; 157 dissections). Node yield relative to levels dissected and incidence of ECS were examined.Dissection-specific node yield was greater in the surgery first group for dissection of levels I-V (31.1 ± 16.7 vs 24.0 ± 14.7, P < .001) and levels II-V (26.7 ± 14.4 vs 21.1 ± 10.7). Extracapsular spread incidence was 32.1% (98/305) in the surgery first group and 15.4% (23/149) in the radiation first group ( P < .001).This study clarifies anticipated node yield based on number of levels dissected and presence of preoperative radiation. Node yield and incidence of ECS are lower in patients undergoing preoperative radiation.
Abstract Background Swallowing dysfunction after radiotherapy (RT) for head and neck cancer can be devastating. A randomized control trial compared swallow exercises versus exercise plus neuromuscular electrical stimulation therapy and found no overall difference in outcomes. Methods Quality of life (QOL), diet, and swallowing variables collected at discrete intervals on 117 patients were reanalyzed to test the hypothesis that shorter time between the completion of radiotherapy and beginning of the swallowing therapy program yielded improved outcomes. Results At baseline, subjects < 1 year post radiation had significantly better function than subjects >2 years post RT in several measures. Over the therapy program, the early group showed significant improvement in diet and QOL. Swallowing physiologic variables showed no difference between groups. Conclusion Beginning a swallowing therapy program within 1 year of completion of radiotherapy demonstrates more consistent improvement in QOL and diet performance compared to later periods.
We determined the relationship between human papillomavirus (HPV) infection and the HPV types detected in 44 patients with squamous cell carcinoma, 10 laryngeal leukoplakia patients, and 12 patients evaluated for benign laryngeal conditions (controls). The sources of HPV DNA were from brushings from the upper respiratory tract and lesion (benign or malignant), oral rinses, and biopsies of patient lesions. Polymerase chain reaction (PCR) and DNA sequencing were used to identify and type HPV. We detected HPV in 25.0% (11/44) of patients with laryngeal cancer, in 30.0% (3/10) of patients with laryngeal leukoplakia, and in 16.7% (2/12) of noncancer controls. Patients with cancer were not more likely to be identified with oncogenic HPV types ( 18.2%) than either the leukoplakia group (20%) or the control group (16.7%). An increased risk of disease was associated with current tobacco use and former alcohol drinking in cancer patients versus controls and in leukoplakia patients versus controls (all p < .05). After we controlled for tobacco and alcohol effects on the risk of disease, exposure to oncogenic HPV types was associated with an increased risk of laryngeal cancer (odds ratio = 3.0) and of laryngeal leukoplakia (odds ratio = 6.0) compared to controls, although the results were not statistically significant. This study suggests that although HPV infection and HPV oncogenic types are not found at a higher frequency in laryngeal cancer or laryngeal leukoplakia as compared to controls, infection is associated with an increased risk of disease after controlling for the effects of alcohol and tobacco use.
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