Deep brain stimulation improves cerebellar tremor symptoms in paraneoplastic cerebellar degeneration: a case report.

Paraneoplastic cerebellar degeneration (PCD) is a rare neurological syndrome caused by a remote effect or immune response involving the cerebellum due to tumor. Here, we report a rare case of PCD secondary to ovarian cancer, presenting clinically with cerebellar tremor. The patient presented with involuntary movements affecting the head, neck, and limbs, along with ataxia and horizontal nystagmus. After conventional medical treatments proved ineffective, the patient underwent a multidisciplinary assessment and received approval from the Institutional Review Board at Affiliated Nanjing Brain Hospital, Nanjing Medical University, to consent to deep brain stimulation (DBS) targeting the ventral intermediate nucleus (VIM) of the thalamus. During the 18-month follow-up, the frequency and amplitude of the tremor significantly improved, with the TRS (1-9) total score decreasing to 23, a 64.06% improvement compared to preoperative levels. The ADL scale score increased from 10 preoperatively to 35, indicating a significant improvement in quality of life. Additionally, the patient's cognitive and ataxic symptoms did not worsen. These results suggest significant improvement in symptoms compared to baseline, with enhanced daily life activities and improved quality of life.