Altered Processing of Complex Visual Stimuli in Patients with Postconcussive Visual Motion Sensitivity

BACKGROUND AND PURPOSE

Vestibular symptoms are common after concussion. Vestibular Ocular Motor Screening identifies vestibular impairment, including postconcussive visual motion sensitivity, though the underlying functional brain alterations are not defined. We hypothesized that alterations in multisensory processing are responsible for postconcussive visual motion sensitivity, are detectable on fMRI, and correlate with symptom severity.

MATERIALS AND METHODS

Twelve patients with subacute postconcussive visual motion sensitivity and 10 healthy control subjects underwent vestibular testing and a novel fMRI visual-vestibular paradigm including 30-second "neutral" or "provocative" videos. The presence of symptoms/intensity was rated immediately after each video. fMRI group-level analysis was performed for a "provocative-neutral" condition. Z-statistic images were nonparametrically thresholded using clusters determined by Z > 2.3 and a corrected cluster significance threshold of P = .05. Symptoms assessed on Vestibular Ocular Motor Screening were correlated with fMRI mean parameter estimates using Pearson correlation coefficients.

RESULTS

Subjects with postconcussive visual motion sensitivity had significantly more Vestibular Ocular Motor Screening abnormalities and increased symptoms while viewing provocative videos. While robust mean activation in the primary and secondary visual areas, the parietal lobe, parietoinsular vestibular cortex, and cingulate gyrus was seen in both groups, selective increased activation was seen in subjects with postconcussive visual motion sensitivity in the primary vestibular/adjacent cortex and inferior frontal gyrus, which are putative multisensory visual-vestibular processing centers. Moderate-to-strong correlations were found between Vestibular Ocular Motor Screening scores and fMRI activation in the left frontal eye field, left middle temporal visual area, and right posterior hippocampus.

CONCLUSIONS

Increased fMRI brain activation in visual-vestibular multisensory processing regions is selectively seen in patients with postconcussive visual motion sensitivity and is correlated with Vestibular Ocular Motor Screening symptom severity, suggesting that increased visual input weighting into the vestibular network may underlie postconcussive visual motion sensitivity.

Postural control strategy after incomplete spinal cord injury: effect of sensory inputs on trunk-leg movement coordination

BACKGROUND

Postural control is affected after incomplete spinal cord injury (iSCI) due to sensory and motor impairments. Any alteration in the availability of sensory information can challenge postural stability in this population and may lead to a variety of adaptive movement coordination patterns. Hence, identifying the underlying impairments and changes to movement coordination patterns is necessary for effective rehabilitation post-iSCI. This study aims to compare the postural control strategy between iSCI and able-bodied populations by quantifying the trunk-leg movement coordination under conditions that affects sensory information.

METHODS

13 individuals with iSCI and 14 aged-matched able-bodied individuals performed quiet standing on hard and foam surfaces with eyes open and closed. We used mean Magnitude-Squared Coherence between trunk-leg accelerations measured by accelerometers placed over the sacrum and tibia.

RESULTS

We observed a similar ankle strategy at lower frequencies (f ≤ 1.0 Hz) between populations. However, we observed a decreased ability post-iSCI in adapting inter-segment coordination changing from ankle strategy to ankle-hip strategy at higher frequencies (f > 1.0 Hz). Moreover, utilizing the ankle-hip strategy at higher frequencies was challenged when somatosensory input was distorted, whereas depriving visual information did not affect balance strategy.

CONCLUSION

Trunk-leg movement coordination assessment showed sensitivity, discriminatory ability, and excellent test-retest reliability to identify changes in balance control strategy post-iSCI and due to altered sensory inputs. Trunk-leg movement coordination assessment using wearable sensors can be used for objective outcome evaluation of rehabilitative interventions on postural control post-iSCI.

Periventricular White Matter Abnormalities on Diffusion Tensor Imaging of Postural Instability Gait Disorder Parkinsonism

BACKGROUND AND PURPOSE

Postural instability gait disorder is a motor subtype of Parkinson disease associated with predominant gait dysfunction. We investigated the periventricular white matter comprising longitudinal, thalamic, and callosal fibers using diffusion tensor MR Imaging and examined clinical correlates in a cohort of patients with Parkinson disease and postural instability gait disorder and healthy controls.

MATERIALS AND METHODS

All subjects underwent the Tinetti Gait and Balance Assessment and brain MR imaging. The DTI indices (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity) from ROIs dropped over the superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, anterior thalamic radiation, anterior and posterior limbs of the internal capsule, and the genu and body of corpus callosum were evaluated.

RESULTS

Our findings showed that the superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, anterior thalamic radiation, genu of the corpus callosum, and body of the corpus callosum are more affected in postural instability gait disorder than in those with Parkinson disease or healthy controls, with more group differences among the longitudinal fibers. Only the callosal fibers differentiated the postural instability gait disorder and Parkinson disease groups. DTI measures in the superior longitudinal fasciculus, frontostriatal fibers (anterior thalamic radiation, anterior limb of the internal capsule), and genu of the corpus callosum fibers correlated with clinical gait severity.

CONCLUSIONS

Findings from this case-control cohort lend further evidence to the role of extranigral pathology and, specifically, the periventricular fibers in the pathophysiology of postural instability gait disorder.

Cheiro-Oral syndrome caused by thalamus hemorrhage: A case report

RATIONALE

Cheiro-Oral syndrome (COS) is a pure sensory deficit confined to the perioral area and ipsilateral distal fingers or hand. Owing to relatively minor clinical findings and various presentations in different cases, the insidious and severe illness it implies may be overlooked at acute settings.

PATIENT CONCERNS

A 70-year-old man with history of hypertension and type II diabetes mellitus under regular medication control came to our emergency department with chief complaint of sudden onset of right perioral region and right upper limb numbness. General physical and neurological examinations were normal except for subtle hypoesthesia to light touch, and pinprick in the right corner of mouth and right forearm to distal fingers.

DIAGNOSES

Routine blood analysis was all in normal range including white blood cell count, hemocrit platelet, renal and liver function, and electrolytes such as sodium and potassium. Noncontrast brain computed tomography showed abnormal high-attenuation collection in the left thalamus.

INTERVENTION

Follow-up computed tomography showed absorption of the hemorrhage after strict control of his blood pressure.

OUTCOMES

The patient was discharged 7 days later from our hospital with stable condition.

LESSONS

We demonstrated type I COS associated with thalamic hemorrhage to highlight the neurological implication of COS. It is crucial for emergency clinicians to recognize the symptoms and promptly order a neuroimaging study to exclude large infarction/hemorrhage, which would deeply affect the disposition and following treatment of the patient.

Salience Network Connectivity in Autism Is Related to Brain and Behavioral Markers of Sensory Overresponsivity

OBJECTIVE

The salience network, an intrinsic brain network thought to modulate attention to internal versus external stimuli, has been consistently found to be atypical in autism spectrum disorders (ASD). However, little is known about how this altered resting-state connectivity relates to brain activity during information processing, which has important implications for understanding sensory overresponsivity (SOR), a common and impairing condition in ASD related to difficulty downregulating brain responses to sensory stimuli. This study examined how SOR in youth with ASD relates to atypical salience network connectivity and whether these atypicalities are associated with abnormal brain response to basic sensory information.

METHOD

Functional magnetic resonance imaging was used to examine how parent-rated SOR symptoms related to salience network connectivity in 61 youth (aged 8-17 years; 28 with ASD and 33 IQ-matched typically developing youth). Correlations between resting-state salience network connectivity and brain response to mildly aversive tactile and auditory stimuli were examined.

RESULTS

SOR in youth with ASD was related to increased resting-state functional connectivity between salience network nodes and brain regions implicated in primary sensory processing and attention. Furthermore, the strength of this connectivity at rest was related to the extent of brain activity in response to auditory and tactile stimuli.

CONCLUSION

Results support an association between intrinsic brain connectivity and specific atypical brain responses during information processing. In addition, findings suggest that basic sensory information is overly salient to individuals with SOR, leading to overattribution of attention to this information. Implications for intervention include incorporating sensory coping strategies into social interventions for individuals with SOR.

Use of panoramic radiography to predict postsurgical sensory impairment following extraction of impacted mandibular third molars

BACKGROUND

The purpose of this study was to use panoramic radiographic findings to predict postsurgical sensory impairment following the extraction of impacted mandibular third molars.

METHODS

There were 120 patients enrolled in this study (55 male and 65 female). A total of 120 impacted mandibular third molars were included due to the proximity between the inferior alveolar nerve (IAN) canal and the roots of the impacted third molar on the panoramic radiograph. Seven radiographic signs were the predictor variables: (1) darkening of the root(s); (2) interruption of the radiopaque line of the inferior alveolar canal; (3) diversion of the inferior alveolar canal; (4) dark and bifid apex; (5) deflection of the root(s); (6) narrowing of the inferior alveolar canal; and (7) narrowing of the root(s). The outcome variable was the postoperative IAN sensory impairment. The retrospective cohort study model was used, and univariable and bivariable statistics was computed with the statistically significant level at p ≤ 0.05.

RESULTS

Three of the radiographic signs were statistically associated with IAN sensory impairment (p<0.05). They include: (1) interruption of the radiopaque line [sensitivity = 0.92, specificity = 0.45, positive predictive value (PPV) = 0.17, negative predictive value (NPV) = 0.02]; (2) diversion of the IAN canal (sensitivity = 0.77, specificity = 0.84, PPV = 0.37, NPV = 0.03); and (3) narrowing of the IAN canal (sensitivity = 0.69, specificity = 0.65, PPV = 0.19, NPV = 0.05). However, the other four radiographic signs, namely darkening of the root(s), dark and bifid apex, deflection of the root(s), and narrowing of the root(s), were not statistically associated with IAN sensory impairment (p>0.05).

CONCLUSION

There are three radiographic signs: (1) interruption of the radiopaque line; (2) diversion of the IAN canal; and (3) narrowing of the IAN canal. These signs are valuable in presurgical evaluation of the risk of postoperative sensory impairment after surgical removal of impacted mandibular third molar.

Partial Sensory and Motor Deficit of Ipsilateral Lower Limb After Continuous Interscalene Brachial Plexus Block

We describe a partial sensory and motor block of the ipsilateral lower limb after interscalene infusion. After and injection of 20 mL of ropivacaine through the needle, the catheter was advanced 5 cm, and an infusion of ropivacaine 0.2% 5 mL/h commenced. Six hours later, the patient reported a left sensory and motor hemisyndrome, which resolved after the infusion was discontinued. Cervical computed tomography showed the tip of the catheter close to the intervertebral foramen at the C7-T1 level and several intravertebral paramedullar air bubbles. We conclude that the neurological symptoms were caused by an injection of local anesthetic via an interscalene catheter placed in proximity to the epidural space. To avoid this complication, we recommend advancing the catheter no more than 2-3 cm and performing frequent neurological evaluation of patients.

Technical difficulties and perioperative complications of retrogasserian glycerol rhizotomy for trigeminal neuralgia

In 139 patients, 260 consecutive retrogasserian glycerol rhizotomies for trigeminal neuralgia were retrospectively analyzed regarding technical surgical difficulties and immediate and early complications. Technical obstacles occurred in 47.3%. In 21 cases (8.1%), the surgical procedure had to be interrupted due to circumstances such as vasovagal reactions, cardiac arrest, or difficulties to find the trigeminal cistern. Complications or side effects, being either transient or persistent, occurred in 67.3%. In the vast majority, those unwanted effects were related to mild sensory deficits. However, in 28.1% the complications were other than mild affection of facial sensibility. These slightly graver complications included labial herpes (3.8%), anesthesia dolorosa (0.8%), moderate or severe affection of sensibility (18.8%), dysesthesia (22.7%), chemical meningitis (1.5%) and infectious meningitis (1.5%). In 5 patients (1.9%) hearing was affected. In one of them, this condition was also brought about by tinnitus, and in another patient a preexisting tinnitus deteriorated. Although the frequency of surgical difficulties was high, the success of the glycerol injection was hampered only in a minor number of procedures. The frequency of complications and side effects was high, but they were mostly mild due to their nature and non-disabling for the patient. However, long-lasting disabling side effects occurred, and this should not be neglected when informing patients preoperatively. The surgical training needed to perform the procedure is stressed, and the use of prophylactic antibiotics when accidentally penetrating the oral bucca is recommended. We consider retrogasserian glycerol rhizotomy to be a good surgical option for patients with trigeminal neuralgia not suitable for microvascular decompression and when pharmacological therapy is not sufficient or is not tolerated.

Clinical-radiologic correlations in pure sensory stroke

Clinical-radiologic correlations in 27 patients with pure sensory strokes (PSS) were retrospectively studied. Dysesthesias from pontine lesions were more severe than those from thalamic lesions. Pontine PSS but not thalamic PSS selectively affected vibration and position sense, leaving pinprick and temperature perceptions intact. Thalamic lesions but not pontine tended to spare the trunk.

Is olfactory reference syndrome an obsessive-compulsive spectrum disorder?: two cases and a discussion

A number of disorders characterized by intrusive repetitive symptoms and varying degrees of insight may overlap phenomenologically and neurobiologically with obsessive-compulsive disorder (OCD). There is a question as to whether olfactory reference syndrome, a disorder characterized by persistent preoccupations about body odor accompanied by shame and embarrassment, is also an OCD spectrum disorder. Two cases of olfactory reference syndrome, with accompanying phenomenological and neurobiological data, are presented in order to discuss the possible overlap with OCD. A number of phenomenological and neurobiological features in these patients were at least partially reminiscent of OCD. In particular, despite having poor insight, both patients demonstrated significant improvement upon treatment with a serotonin reuptake inhibitor.

[The value of computed tomography in persistent balance disorders following the use of stapes prostheses]

10 of 150 patients had persistent vertigo after implantation of stapes prostheses. These patients were evaluated by high-resolution CT in the axial and coronal plane. Scans showed in all cases findings which related to the symptoms. The CT findings were proved intraoperatively in 9 cases. A new indirect sign of a perilymphatic fistula is described in form of an air bulla at the end of the prosthesis. Retympanotomy could be planned better with the help of HR-CT.