Translate this page into:
Neurovascular Conflicts of the Anterior Inferior Cerebellar Artery: A Case Series from a Psychiatry Outpatient Department
*Corresponding author: Deepti Jigdung, PGT Department of Psychiatry, Gauhati Medical College and Hospital, Bhangagarh, Guwahati, Assam, India. jigdungdeepti22@gmail.com
-
Received: ,
Accepted: ,
How to cite this article: Medhi D, Jigdung D, Hussain SI. Neurovascular Conflicts of the Anterior Inferior Cerebellar Artery: A Case Series from a Psychiatry Outpatient Department. Acad Bull Ment Health. 2026;4:70-2. doi: 10.25259/ABMH_54_2025
Abstract
Neurovascular conflicts (NVCs) involving the anterior inferior cerebellar artery (AICA) are increasingly recognized as contributors to both classical neurological syndromes and atypical psychiatric presentations. This case series describes two patients—a young female with somatoform-like symptoms and an elderly male with affective disturbances—who were referred to psychiatry and later diagnosed with AICA neurovascular loops on magnetic resonance imaging (MRI). These cases highlight the importance of neuroimaging in persistent psychiatric symptoms and underscore the need for interdisciplinary diagnostic strategies.
Keywords
Anterior inferior cerebellar artery loop
Constructive interference in steady state sequencing
High-resolution magnetic resonance imaging
Neurovascular conflict
Somatoform symptoms
INTRODUCTION
Neurovascular conflict (NVC) is defined as the compression of cranial nerves by adjacent vascular structures, typically at the root entry zone, a vulnerable transition zone between central and peripheral myelin.[1,2] The anterior inferior cerebellar artery (AICA), arising from the basilar artery, is frequently implicated in NVCs due to its tortuous course and proximity to cranial nerves VII (facial) and VIII (vestibulocochlear). While traditionally associated with hemifacial spasm, tinnitus, and vertigo, recent studies suggest that AICA loops may also contribute to psychiatric symptoms through chronic sensory irritation and brainstem dysregulation.[3]
Anatomical variations in AICA loops are common. Imaging studies report AICA loop prevalence within the internal auditory canal (IAC) ranging from 14% to 34%, while cadaveric studies suggest a broader range of 13% to 40%. Notably, up to 75% of neurovascular compression syndromes involving cranial nerves are attributed to AICA loops. AICA loops are classified based on their anatomical relationship with the IAC: Type I: Loop remains within the cerebellopontine angle. Prevalence: ~60–70%. Clinical Relevance: May cause indirect compression; associated with tinnitus and vertigo. Type II: Loop enters <50% of the IAC. Prevalence: ~20–30%. Clinical Relevance: Higher risk of direct nerve contact; linked to vestibular symptoms. Type III: Loop extends >50% into the IAC. These loops may cause mechanical irritation, demyelination, and ectopic impulse generation, potentially leading to sensory disturbances, mood dysregulation, and somatoform features. Despite their clinical relevance, AICA-related NVCs remain underdiagnosed, particularly in psychiatric settings. High-resolution magnetic resonance imaging (MRI) with constructive interference in steady state (CISS) sequencing is essential for identifying subtle vascular loops that may be missed on conventional imaging.[4] This case series presents two patients referred to the Psychiatry Outpatient Department (OPD) at Gauhati Medical College and Hospital, whose persistent symptoms were ultimately linked to AICA neurovascular loops. Their presentations challenge traditional diagnostic boundaries and advocate for integrative neuropsychiatric assessment.
CASE SERIES
Case 1
Somatoform-like presentation in a young female. A 20-year-old woman from Kamrup Metro, Assam, presented to the Psychiatry OPD at Gauhati Medical College and Hospital on 24th October 2024. She was referred from the Neurology OPD with complaints of decreased energy, giddiness, a sensation of impending fall while standing in queues, and marked irritability.
On detailed history-taking, it was revealed that her symptoms began approximately five months back following an episode of fever, vomiting, and episodic breathing difficulty that required hospitalization. After discharge, she began experiencing sleep disturbances, primarily in sleep maintenance, waking up repeatedly during the night. In an effort to improve her condition, she enrolled in yoga classes, which initially seemed beneficial. However, within a few days, she started experiencing a crawling sensation over her back, described as a movement from below upward. This sensation caused significant discomfort and persistent worry about her health. Her sleep disturbances worsened, now affecting both initiation and maintenance. She developed generalized weakness, an inability to attend college, and frequently insisted that her family take her to the hospital. Despite multiple consultations with private physicians, her condition did not improve. She began experiencing giddiness while walking, too. These physical symptoms made her very sad and irritable. Later, she started having suicidal ideation.
She was taken to the Department of Otorhinolaryngology, Gauhati Medical College and Hospital (GMCH), Assam, where Pure Tone Audiometry was performed and found to be normal. Subsequently, she was referred to the Neurology Department of GMCH for further evaluation. A CT Brain and an EEG were conducted, both of which revealed no abnormalities. She was discharged with multivitamins and referred to the Psychiatry OPD with a provisional diagnosis of somatoform disorder. Upon presentation to the Psychiatry OPD, she was admitted and started on Tablet Escitalopram 10 mg, Tablet Clonazepam 0.5 mg, and intravenous fluids. All blood parameters were within normal limits, and systemic examination revealed no significant findings. After 20 days of inpatient care, her symptoms began to improve, except for persistent giddiness. An MRI of the brain was advised prior to discharge. On follow-up, she returned with MRI Brain reports including CISS sequencing, which revealed a Type II AICA loop on the right side, a Type I AICA loop on the left side, no significant neuroparenchymal abnormalities, and no filling defect on MRI Venography. Neurology opinion was sought for vertigo and MRI findings. She has since been maintained on Tablet Escitalopram 10 mg, Tablet Clonazepam 0.5 mg, and Tablet Oxcarbazepine extended release 150 mg once daily. She continues to follow up regularly and remains clinically stable on this regimen.
Case 2
Affective Symptoms in an Elderly Male. A 70-year-old male from Kamrup Rural, Assam, presented to the Psychiatry OPD on 17th June 2025 with complaints of a crawling sensation over the middle of his scalp, leading to a persistent headache of mild intensity occurring throughout the day and night. The headache had no identifiable aggravating or relieving factors. Gradually, he developed a ringing sensation in his left ear, which significantly disturbed his sleep, causing multiple awakenings at night over the past two years. He was previously discharged with medications and advised to attend the ENT OPD GMCH for further evaluation of his tinnitus. Pure Tone Audiometry was performed and found to be normal. He was advised to continue medications as prescribed by the Psychiatry OPD. Approximately 15 days prior to his follow-up visit, his family observed a noticeable decline in his mood. The patient himself reported low mood and frequent crying spells, especially when asked about his health condition. He became restless, expressed significant distress due to his symptoms, and began refusing oral intake of food. He was admitted via the Psychiatry OPD on 22nd July 2025 and started Tablet Escitalopram 10 mg, Tablet Clonazepam 0.5 mg, Tablet Gabapentin 400 mg, and Tablet Nortriptyline 10 mg. A comprehensive evaluation was conducted, including general and systemic examination. All blood parameters were within normal limits. MRI brain revealed a Type I NVCs of AICA with the left facial nerve, an arachnoid cyst along the left inferior temporal lobar convexity, and cerebral atrophic changes. Based on clinical response, the dose of Escitalopram was increased to 15 mg, and Tablet Eslicarbazepine 400 mg was added. The patient demonstrated significant symptom improvement and was discharged on the same medication regimen. He continued to maintain clinical stability on follow-up.
DISCUSSION
These cases illustrate the diagnostic complexity of NVCs presenting with psychiatric symptoms. In both patients, conventional investigations failed to reveal abnormalities, and symptoms were initially attributed to primary psychiatric disorders. However, persistent and atypical features—such as crawling sensations, giddiness, and refractory sleep disturbances —prompted further neuroimaging, which revealed AICA loops suggestive of neurovascular compression.
Compression of cranial nerves or brainstem structures by AICA loops may disrupt afferent sensory signaling and autonomic regulation, contributing to somatoform and affective symptoms. The young female’s presentation mimicked somatoform disorder, while the elderly male’s symptoms aligned with major depressive disorder with somatic features. These findings support the hypothesis that structural anomalies of the brain may underlie certain psychiatric presentations.
Treatment with SSRIs, anticonvulsants, and mood stabilizers proved effective, suggesting a role for neuromodulatory pharmacotherapy in NVC-related psychiatric symptoms. These cases advocate for the use of high-resolution MRI in refractory psychiatric presentations and highlight the importance of interdisciplinary collaboration.
CONCLUSION
NVCs involving the AICA can present with atypical psychiatric symptoms that mimic primary psychiatric disorders. These cases underscore the need for heightened clinical suspicion and advanced neuroimaging in persistent, unexplained presentations. Recognizing the neurovascular basis of certain psychiatric symptoms may lead to more targeted and successful treatment strategies.
Acknowledgment:
The authors thank the Department of Psychiatry, Neurology, ENT, and Radiology teams for their clinical and diagnostic excellence, and the patients and families for their trust and consent, enabling this academic co’ntribution.
Authors’ contributions:
DM: Concepts, design, definition of intellectual content, literature search, clinical studies, experimental studies, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing and review; DJ: Clinical studies, literature search, data acquisition, manuscript preparation; SIH: Clinical studies, data acquisition, manuscript preparation, literature search.
Ethical approval:
Institutional Review Board approval is not required.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for clinical information to be reported in the journal. The patient understand that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil
References
- Unveiling clinicodiagnostic and therapeutic insights of AICA loop of vestibulocochlear nerve. SN Compr Clin Med. 2025;7:90.
- [CrossRef] [Google Scholar]
- The anterior inferior cerebellar artery variability in the context of neurovascular compression syndromes. Biomedicines. 2024;12:452.
- [CrossRef] [PubMed] [Google Scholar]
- Anterior inferior cerebellar artery syndrome: Fact or fiction. Clin Otolaryngol Allied Sci. 2003;28:75-80.
- [CrossRef] [PubMed] [Google Scholar]
- Anterior inferior cerebellar artery–neurovascular conflict causing pulsatile tinnitus. AJNR 2022 Available from: https://share.google/aOpAlwqQ6Vjnm1irp [accessed 2025 May 25]
- [Google Scholar]