[Image Diagnosis for Hemifacial Spasm].

Cisternography using heavy T2-weighted images from 3-Tesla magnetic resonance imaging(MRI)and three-dimensional time-of-flight MR angiography(3D TOF MRA)is useful for identifying conflicting vessels in primary hemifacial spasm(HFS). Cisternography provides high-signal images of the cerebrospinal fluid and low-signal images of the cranial nerves and cerebral blood vessels, whereas 3D TOF MRA provides high-signal images with only vascular information. The combination of these two methods increases the identification rate of conflicting vessels. The neurovascular conflict(NVC)site in HFS is where the facial nerve exits the brainstem. However, on MRI, the true NVC site is often more proximal than the facial nerve attachment to the brainstem. On preoperative MRI, it is important to not miss the blood vessels surrounding the proximal portion of the facial nerve. If multiple compression vessels or deep vessels are located in the supraolivary fossette, they may be missed. Coronal section imaging and multiplanar reconstruction(MPR)minimize the chances of missing a compression vessel. Preoperative MRI and CT can also provide various other information, such as volume of the cerebellum, presence of emissary veins, shape of the petrosal bone, and size of the flocculus.

Preoperative findings in relation to the usefulness of endoscopic assistance for microvascular decompression.

PURPOSE: Endoscopy is known to be a useful adjunct for microvascular decompression (MVD) surgery, assisting observation in blind spots such as Meckel's cave in cases of trigeminal neuralgia (TN) and the root exit zone (REZ) in hemifacial spasm (HFS). However, few reports have discussed the usefulness of endoscopy in relation to individual patient characteristics or preoperative magnetic resonance imaging (MRI). METHODS: We retrospectively reviewed the medical records of 109 patients (98 with HFS and 11 with TN, 85 women, median age 55 years) who had undergone endoscopically assisted MVD at our institution between 2017 and 2021. The usefulness of endoscopy in individual cases was scored by three neurosurgeons using a grading scale: 2, essential and indispensable; 1, useful and helpful; 0, not necessary. The mean value of the assigned scores was taken as an indicator of "usefulness," and endoscopy was considered to have been "useful" in cases with a score of > 1.0. RESULTS: Endoscopic assistance was judged to have been useful in 69% of the patients. The proportion of patients evaluated as useful was significantly lower for TN (18.2%) than for HFS (74.5%). Patients with superior cerebellar artery compression had significantly lower scores than patients with other vessels. Endoscopy was considered useful in a significantly higher proportion of patients with anatomically complicated offending vessels (bifurcation or strong meandering) in the REZ detected by preoperative MRI (P < 0.005). CONCLUSION: Endoscopy for MVD is useful for patients with HFS, especially when preoperative MRI shows bifurcation or strongly meandering vessels in the REZ.

Intracranial Neurofeedback Modulating Neural Activity in the Mesial Temporal Lobe During Memory Encoding: A Pilot Study.

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.

[Technique of Microvascular Decompression for Hemifacial Spasm Based on Surgical Anatomy].

This article describes the anatomical approach and operative points of microvascular decompression for hemifacial spasm based on the author's personal experience with 1,000 cases. As vascular compression of the facial nerve is often quite caudal, it is necessary to ensure that the compressing arteries in this area are moved. Neither the vessels nor the prosthesis used to move them should not touch the root exit zone of the nerve(vascular transposition nerve isolation technique). It should also be emphasized that every effort should be made to avoid complications such as hearing impairment and postoperative subcutaneous spinal fluid accumulation.

Musical Auditory Alpha Wave Neurofeedback: Validation and Cognitive Perspectives.

Neurofeedback through visual, auditory, or tactile sensations improves cognitive functions and alters the activities of daily living. However, some people, such as children and the elderly, have difficulty concentrating on neurofeedback for a long time. Constant stressless neurofeedback for a long time may be achieved with auditory neurofeedback using music. The primary purpose of this study was to clarify whether music-based auditory neurofeedback increases the power of the alpha wave in healthy subjects. During neurofeedback, white noise was superimposed on classical music, with the noise level inversely correlating with normalized alpha wave power. This was a single-blind, randomized control crossover trial in which 10 healthy subjects underwent, in an assigned order, normal and random feedback (NF and RF), either of which was at least 4 weeks long. Cognitive functions were evaluated before, between, and after each neurofeedback period. The secondary purpose was to assess neurofeedback-induced changes in cognitive functions. A crossover analysis showed that normalized alpha-power was significantly higher in NF than in RF; therefore, music-based auditory neurofeedback facilitated alpha wave induction. A composite category-based analysis of cognitive functions revealed greater improvements in short-term memory in subjects whose alpha-power increased in response to NF. The present study employed a long period of auditory alpha neurofeedback and achieved successful alpha wave induction and subsequent improvements in cognitive functions. Although this was a pilot study that validated a music-based alpha neurofeedback system for healthy subjects, the results obtained are encouraging for those with difficulty in concentrating on conventional alpha neurofeedback.Trial registration: 2018077NI, date of registration: 2018/11/27.

Deep Brain Stimulation Leads to Long-term Improvement of Neuropathic Tremor due to Chronic Inflammatory Demyelinating Polyneuropathy: A Case Report.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a peripheral neuropathy caused by immune-mediated demyelination, causing tremors in 3.9%-58% of affected patients. This neuropathic tremor may persist after treatment and is known to be refractory to conventional medication. We present two cases of neuropathic tremor due to CIDP in which deep brain stimulation (DBS) over a long-term period led to marked improvement. Case 1: A 66-year-old woman presented with severe 2-3-Hz resting, postural, and kinetic tremors of both hands. The tremor was refractory to medication but improved well after bilateral VIM-DBS. However, 2 months after the procedure, the tremor worsened and was accompanied by sensory disturbance in the extremities. A diagnosis of CIDP was made, and treatment with corticosteroids and intravenous immunoglobulin achieved remission 6 months later. Although there was residual tremor after CIDP remission, it has been well controlled by DBS for the last 10 years. Case 2: A 56-year-old man presented with a 6-year history of CIDP after developing sensory dullness and tremors in the extremities. The CIDP had gone into remission 1 year previously and the sensory deficits had improved, but the tremors had gradually worsened: severe 8-12-Hz postural, kinetic, and resting tremors were present in both upper extremities. Right VIM-DBS was performed and the tremors on the left side showed marked improvement. Over the next 8 years, the tremors were well controlled and there were no relapses of CIDP. DBS may achieve long-term improvement of neuropathic tremor caused by CIDP if the CIDP is in remission.

A Case of Unilateral Facial Spasm With Vulnerable Hearing Function Due to a History of Cisplatin Treatment, Resulting in Intraoperative Hearing Loss.

A 51-year-old man with a history of cisplatin treatment for a right testicular tumor underwent microvascular decompression for hemifacial spasm. At an early stage in the surgical procedure, the intraoperative auditory brainstem response (ABR) was diminished despite a relatively minimally invasive approach, resulting in irreversible hearing loss. Cisplatin is known to cause dose-dependent hearing impairment primarily affecting the cochlea, but it can also induce neurotoxicity. In the present case, prior cisplatin administration may have caused fragility of the cochlear nerve as well. Patients with a history of ototoxic and neurotoxic drugs such as cisplatin require more careful manipulation and thorough intraoperative auditory monitoring during neurosurgical procedures that may affect hearing, such as those for hemifacial spasms.

Is Common Trunk Anomaly Frequent in Hemifacial Spasm? Comparison with Normal Subjects Using Magnetic Resonance Imaging.

OBJECTIVE: Hemifacial spasm (HFS) results from vascular compression at the root exit of the facial nerve. Although the underlying etiology has yet to be identified, it has been suggested that congenital vascular anomalies are involved. We have hypothesized common trunk anomaly of the anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) which may play a role in HFS. However, no previous studies have directly compared the incidence of this anomaly between HFS patients and normal subjects. The present study was designed to address this gap in the literature. METHODS: This case-control study compared magnetic resonance angiography data from 65 HFS patients and 65 normal subjects. Dominant AICA/PICA is defined as the absence of PICA/AICA, with the remaining AICA/PICA supplying both vascular territories. The term "common trunk" encompasses both dominant AICA and dominant PICA. The frequency of common trunk and dominant AICA/PICA was compared between the 2 groups. RESULTS: There were no significant differences in the incidence of a common trunk (68.5% and 64.6%), dominant AICA (30.8% and 32.3%) and dominant PICA (37.7% and 32.3%) between the 2 groups. Additionally, no differences were found in the frequency of atherosclerosis risk factors. CONCLUSIONS: There was no apparent association between common trunk anomaly and HFS. It is suspected that some vascular anomalies other than a common trunk are involved in HFS.

Bilateral Low-Frequency Hearing Impairment After Microvascular Decompression Surgery.

BACKGROUND: Hearing impairment is an important complication of microvascular decompression (MVD). In patients after MVD, we have occasionally noted slight to moderate hearing deterioration at low frequencies that is difficult to detect using pure tone average. OBJECTIVE: To assess the incidence and features of low-frequency hearing impairment (LF-HI) after MVD and evaluate its associated factors. METHODS: This single-center, retrospective observational study assessed the audiometric outcome of 270 patients who underwent MVD between January 2015 and December 2020. Preoperative and postoperative hearing levels were compared for each frequency. LF-HI was defined as a hearing deterioration of ≥15 dB at 125, 250, or 500 Hz. The incidence, symptoms, and associated factors of LF-HI were analyzed. RESULTS: Statistical analysis of the patients overall demonstrated slight but significant decreases in the hearing level after MVD at lower frequencies on both the operative and contralateral sides. Eighty-one patients (30.0%) had LF-HI: 49 on the operative side, 24 on the contralateral side, and 8 on both sides, while pure tone average was worsened in 5 patients (1.8%). Subjective symptoms, including hearing deterioration, ear fullness, tinnitus, and dizziness, developed in 10.4% of the patients with LF-HI but improved subsequently within several weeks. "Older age" and "operative side" were associated with LF-HI. CONCLUSION: Decreases in lower-frequency hearing levels in both the ipsilateral and contralateral (nonoperative) ears were observed after trigeminal neuralgia and hemifacial spasm surgery. LF-HI does not cause permanent symptoms but may be a noteworthy phenomenon, possibly involved in the contralateral hearing loss encountered occasionally after other types of posterior cranial fossa surgery.

Chronic Osteomyelitis of the Cranial Vault in an Adolescent Female: A Case Report.

We report an 18-year-old female patient who developed left temporal headache and fever one month after administration of isotretinoin for acne. Imaging studies demonstrated osteolytic change in the left frontal bone, and the lesion showed gadolinium contrast enhancement. Biopsy confirmed the diagnosis of osteomyelitis, and the symptoms improved after 8 months of medication with antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs). However, the pain recurred when isotretinoin was resumed. Isotretinoin sometimes causes excessive inflammation, which may have been the reason for the osteomyelitis in this case. Although osteomyelitis is usually caused by bacterial infection, a non-bacterial mechanism should also be suspected if the condition is resistant to antibiotics.

Aspiration Surgery with Appropriate Antibiotic Treatment Yields Favorable Outcomes for Bacterial Brain Abscess.

BACKGROUND: Even in the era of advanced medical treatment, brain abscess still has a high mortality rate. At our institution, brain abscess has been treated mainly using stereotactic or echo-guided aspiration followed by relatively long-term antibiotic treatment, achieving favorable outcomes. To evaluate the efficacy of our strategy involving less-invasive aspiration surgery and long-term selective antibiotic administration for brain abscess, a single-institution series of cases was investigated. METHODS: We retrospectively reviewed and analyzed the medical records of 25 cases of brain abscess treated at Saitama Medical University Hospital between 2008 and 2021. The patients comprised 16 men and 9 women aged between 39 and 85 years (median 62 years). Neurosurgical intervention was performed for 23 (92.0%) of the patients and the remaining 2 received antibiotics alone. RESULTS: Among the neurosurgery patients, 22 (95.7%) underwent echo-guided or stereotactic aspiration, and only 1 underwent craniotomy. Anaerobic bacteria were detected in 11 patients. In the surgical and conservative groups, the median duration of antibiotic treatment was 16 weeks and 23 weeks, respectively. Since 2014 when metronidazole first became available, it has replaced meropenem to cover anaerobic bacteria. The overall mortality rate was 4.0% and a favorable outcome (Glasgow Outcome Scale 4 or 5) was achieved in 76% of the patients. There was no surgical mortality or morbidity. CONCLUSIONS: Most patients underwent aspiration surgery and achieved favorable outcomes. Along with antibiotic treatment for a sufficiently long period to cover anaerobes, this approach can be expected to yield good results.

New treatment strategy for chronic low back pain with alpha wave neurofeedback.

The lifetime prevalence of low back pain is 83%. Since there is a lack of evidence for therapeutic effect by cognitive behavioral therapy (CBT) or physical therapy (PT), it is necessary to develop objective physiological indexes and effective treatments. We conducted a prospective longitudinal study to evaluate the treatment effects of CBT, PT, and neurofeedback training (NFT) during alpha wave NFT. The early-chronic cases within 1 year and late-chronic cases over 1 year after the diagnosis of chronic low back pain were classified into six groups: Controls, CBTs, PTs, NFTs, CBT-NFTs, PT-NFTs. We evaluated the difference in EEG, psychosocial factors, scores of low back pain before/after the intervention. Therapeutic effect was clearly more effective in the early-chronic cases. We found that the intensity of alpha waves increased significantly after therapeutic intervention in the NFT groups, but did not have the main effect of reducing low back pain; the interaction between CBT and NFT reduced low back pain. Factors that enhance therapeutic effect are early intervention, increased alpha waves, and self-efficacy due to parallel implementation of CBT/PT and NFT. A treatment protocol in which alpha wave neurofeedback training is subsidiarily used with CBT or PT should be developed in the future.