Changes in cognition and health-related quality of life with unilateral thalamotomy for Parkinsonian tremor

Motor and non-motor outcome in tremor dominant Parkinson's disease after MR-guided focused ultrasound thalamotomy

BACKGROUND AND OBJECTIVES

Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is an emerging technique for the treatment of severe, medication-refractory tremor syndromes. We here report motor and non-motor outcomes 6 and 12 months after unilateral MRgFUS thalamotomy in tremor-dominant Parkinson's disease (tdPD).

METHODS

25 patients with tdPD underwent neuropsychological evaluation including standardized questionnaires of disability, quality of life (QoL), mood, anxiety, apathy, sleep disturbances, and cognition at baseline, 6 and 12 months after MRgFUS. Motor outcome was evaluated using the Clinical Rating Scale for Tremor (CRST) and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). In addition, side effects and QoL of family caregivers were assessed.

RESULTS

12 months after MRgFUS significant improvements were evident in the tremor subscores. Patients with concomitant rest and postural tremor showed better tremor outcomes compared to patients with predominant rest tremor. There were no differences in the non-motor assessments. No cognitive decline was observed. Side effects were mostly transient (54%) and classified as mild (62%). No changes in the caregivers' QoL could be observed.

CONCLUSION

We found no changes in mood, anxiety, apathy, sleep, cognition or persistent worsening of gait disturbances after unilateral MRgFUS thalamotomy in tdPD. Concomitant postural tremors responded better to treatment than predominant rest tremors.

Cognitive safety of focused ultrasound thalamotomy for tremor: 1-year follow-up results of the COGNIFUS part 2 study

Introduction

In the COGNitive in Focused UltraSound (COGNIFUS) study, we examined the 6-month cognitive outcomes of patients undergoing MRgFUS thalamotomy. This study endorsed the safety profile of the procedure in terms of cognitive functions that cannot be evaluated in real-time during the procedure unlike other aspects. The aim of the COGNIFUS Part 2 study was to investigate the cognitive trajectory of MRgFUS patients over a 1-year period, in order to confirm long-term safety and satisfaction.

Methods

We prospectively evaluated the cognitive and neurobehavioral profile of patients with essential tremor (ET) or Parkinson's Disease (PD) related tremor undergoing MRgFUS thalamotomy at 1 year-follow-up following the treatment.

Results

The sample consists of 50 patients (male 76%; mean age ± SD 69.0 ± 8.56; mean disease duration ± SD 12.13 ± 12.59; ET 28, PD 22 patients). A significant improvement was detected at the 1 year-follow-up assessment in anxiety and mood feelings (Hamilton Anxiety rating scale 5.66 ± 5.02 vs. 2.69 ± 3.76, p ≤ <0.001; Beck depression Inventory II score 3.74 ± 3.80 vs. 1.80 ± 2.78, p = 0.001), memory domains (Rey Auditory Verbal Learning Test, immediate recall 31.76 ± 7.60 vs. 35.38 ± 7.72, p = 0.001 and delayed recall scores 5.57 ± 2 0.75 vs. 6.41 ± 2.48), frontal functions (Frontal Assessment Battery score 14.24 ± 3.04 vs. 15.16 ± 2.74) and in quality of life (Quality of life in Essential Tremor Questionnaire 35.00 ± 12.08 vs. 9.03 ± 10.64, p ≤ 0.001 and PD Questionnaire -8 7.86 ± 3.10 vs. 3.09 ± 2.29, p ≤ 0.001).

Conclusion

Our study supports the long-term efficacy and cognitive safety of MRgFUS treatment for ET and PD.

Differential Cognitive Effects of Unilateral Subthalamic Nucleus Deep Brain Stimulation for Parkinson's Disease

OBJECTIVE

The aim of this study was to investigate the cognitive effects of unilateral directional versus ring subthalamic nucleus deep brain stimulation (STN DBS) in patients with advanced Parkinson's disease.

METHODS

We examined 31 participants who underwent unilateral STN DBS (left n = 17; right n = 14) as part of an National Institutes of Health (NIH)-sponsored randomized, double-blind, crossover study contrasting directional versus ring stimulation. All participants received unilateral DBS implants in the hemisphere more severely affected by motor parkinsonism. Measures of cognition included verbal fluency, auditory-verbal memory, and response inhibition. We used mixed linear models to contrast the effects of directional versus ring stimulation and implant hemisphere on longitudinal cognitive function.

RESULTS

Crossover analyses showed no evidence for group-level changes in cognitive performance related to directional versus ring stimulation. Implant hemisphere, however, impacted cognition in several ways. Left STN participants had lower baseline verbal fluency than patients with right implants (t [20.66 = -2.50, p = 0.02]). Verbal fluency declined after left (p = 0.013) but increased after right STN DBS (p < 0.001), and response inhibition was faster following right STN DBS (p = 0.031). Regardless of hemisphere, delayed recall declined modestly over time versus baseline (p = 0.001), and immediate recall was unchanged.

INTERPRETATION

Directional versus ring STN DBS did not differentially affect cognition. Similar to prior bilateral DBS studies, unilateral left stimulation worsened verbal fluency performance. In contrast, unilateral right STN surgery increased performance on verbal fluency and response inhibition tasks. Our findings raise the hypothesis that unilateral right STN DBS in selected patients with predominant right brain motor parkinsonism could mitigate declines in verbal fluency associated with the bilateral intervention. ANN NEUROL 2024;95:1205-1219.

Differential cognitive effects of unilateral left and right subthalamic nucleus deep brain stimulation for Parkinson disease

Objective

To investigate hemispheric effects of directional versus ring subthalamic nucleus (STN) deep brain stimulation (DBS) surgery on cognitive function in patients with advanced Parkinson's disease (PD).

Methods

We examined 31 PD patients (Left STN n = 17; Right STN n = 14) who underwent unilateral subthalamic nucleus (STN) DBS as part of a NIH-sponsored randomized, cross-over, double-blind (ring vs directional) clinical trial. Outcome measures were tests of verbal fluency, auditory-verbal memory, and response inhibition. First, all participants were pooled together to study the effects of directional versus ring stimulation. Then, we stratified the groups by surgery hemisphere and studied the longitudinal changes in cognition post-unilateral STN DBS.

Results

Relative to pre-DBS cognitive baseline performances, there were no group changes in cognition following unilateral DBS for either directional or ring stimulation. However, assessment of unilateral DBS by hemisphere revealed a different pattern. The left STN DBS group had lower verbal fluency than the right STN group (t(20.66 = -2.50, p = 0.02). Over a period of eight months post-DBS, verbal fluency declined in the left STN DBS group (p = 0.013) and improved in the right STN DBS group over time (p < .001). Similarly, response inhibition improved following right STN DBS (p = 0.031). Immediate recall did not significantly differ over time, nor was it affected by implant hemisphere, but delayed recall equivalently declined over time for both left and right STN DBS groups (left STN DBS p = 0.001, right STN DBS differ from left STN DBS p = 0.794).

Conclusions

Directional and ring DBS did not differentially or adversely affect cognition over time. Regarding hemisphere effects, verbal fluency decline was observed in those who received left STN DBS, along with the left and right STN DBS declines in delayed memory. The left STN DBS verbal fluency decrement is consistent with prior bilateral DBS research, likely reflecting disruption of the basal-ganglia-thalamocortical network connecting STN and inferior frontal gyrus. Interestingly, we found an improvement in verbal fluency and response inhibition following right STN DBS. It is possible that unilateral STN DBS, particularly in the right hemisphere, may mitigate cognitive decline.

Cognitive outcomes after focused ultrasound thalamotomy for tremor: Results from the COGNIFUS (COGNitive in Focused UltraSound) study

INTRODUCTION

Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an innovative method for the unilateral treatment of essential tremor (ET) and Parkinson's disease (PD) related tremor. Our aim was to assess cognitive changes following MRgFUS thalamotomy to better investigate its safety profile.

METHODS

We prospectively investigated the cognitive and neurobehavioral profile of patients consecutively undergoing MRgFUS within a 2-year period. Patients had a comprehensive clinical and neuropsychological assessment before and six months after MRgFUS thalamotomy.

RESULTS

The final sample consisted of 40 patients (males 38; mean age±SD 67.7 ± 10.7; mean disease duration±SD 9.3 ± 5.6; ET 22, PD 18 patients). For the whole sample, improvements were detected in tremor (Fahn-Tolosa-Marin Clinical Rating Scale for tremor 35.79 ± 14.39 vs 23.03 ± 10.95; p < 0.001), anxiety feelings (Hamilton Anxiety rating scale 5.36 ± 3.80 vs 2.54 ± 3.28, p < 0.001), in the overall cognitive status (MMSE 25.93 ± 3.76 vs 27.54 ± 2.46, p 0.003; MOCA 22.80 ± 4.08 vs 24.48 ± 3.13, p < 0.001), and in quality of life (Quality of life in Essential Tremor Questionnaire 36.14 ± 12.91 vs 5.14 ± 6.90, p < 0.001 and PD Questionnaire-8 5.61 ± 4.65 vs 1.39 ± 2.33, p 0.001). No changes were detected in frontal and executive functions, verbal fluency and memory, abstract reasoning and problem-solving abilities.

CONCLUSION

Our study moves a step forward in establishing the cognitive sequelae of MRgFUS thalamotomy and in endorsing effectiveness and safety.

Cognitive effects of unilateral thalamotomy for tremor: a meta-analysis

Tremor is a debilitating symptom that can lead to functional impairment. Pharmacotherapy is often successful, but up to 50% of patients are resistant to medications or cannot tolerate side effects. Thalamotomy to the ventral intermediate nucleus of the thalamus is a surgical intervention for refractory tremor. Thalamotomy surgeries include radiofrequency and incisionless procedures, such as Gamma Knife radiosurgery and magnetic resonance-guided focused ultrasound. Cognitive changes following thalamotomy have been inconsistently reported across studies. We performed a meta-analysis to summarize the impact of unilateral thalamotomy to the ventral intermediate nucleus of the thalamus across multiple cognitive domains. We searched MEDLINE, Embase Classic, Embase and EBM Reviews for relevant studies. Neuropsychological tests were categorized into seven cognitive domains: global cognition, verbal memory, non-verbal memory, executive function, phonemic fluency, semantic fluency and visuospatial processing. We calculated standardized mean differences as Hedges' g and 95% confidence intervals of the change between pre- and postoperative cognitive scores. Pooling of standardized mean differences across studies was performed using random-effects models. Risk of bias across studies and quality of evidence for each cognitive domain were assessed with the National Institute of Health quality assessment tool and the GRADEpro Guideline Development Tool, respectively. Of the 1251 records reviewed, eight studies met inclusion criteria. We included 193 patients with essential tremor, Parkinson's disease, or multiple sclerosis in the meta-analysis. There was a small significant decline in phonemic fluency [standardized mean difference = -0.29, 95% confidence interval: (-0.52, -0.05), P = 0.017] and a trend towards a decline in semantic fluency [standardized mean difference = -0.19, 95% confidence interval: (-0.40, 0.01), P = 0.056]. No postoperative changes were observed in the other cognitive domains (P values >0.14). In secondary analyses, we restricted the analyses to studies using magnetic resonance-guided focused ultrasound given its growing popularity and more precise targeting. In those analyses, there was no evidence of cognitive decline across any domain (P values >0.37). In terms of risk of bias, five studies were rated as 'good' and three studies were rated as 'fair'. According to GRADEpro guidelines, the certainty of the effect for all cognitive domains was low. This study provides evidence that unilateral thalamotomy to the ventral intermediate nucleus of the thalamus is relatively safe from a cognitive standpoint, however, there may be a small decline in verbal fluency. Magnetic resonance-guided focused ultrasound might have a more favourable postoperative cognitive profile compared with other thalamotomy techniques.

Surgical Management of Parkinson’s Disease: The Role of Lesioning Procedures in Developing Countries in the Modern Era

BACKGROUND: The known loss of dopaminergic cells in the pars-compacta of the substantia nigra that is the hallmark of PD. The cellular pathophysiology of the motor dysfunction is beginning to be better understood, thereby providing a stronger scientific rationale for surgical interventions. Yet, to date, there are no treatments that prevent, halt, or cure PD. Surgical strategies, offer symptomatic relief or control of motor complications associated with drug treatment. Both pallidotomy and thalamotomy were extensively used in the treatment of PD in the1950’s and 1960’s. With the introduction of levodopa (L-dopa) in the1960’s and the realization of its striking benefits, surgery was almost abandoned and used only for patients with severe tremor. Surgical therapy is now being used earlier and more often. There are currently three brain regions being considered as targets for functional neurosurgery for PD (other than transplantation). Either CNS lesions (thalamotomy, pallidotomy or subthalamic nucleus lesions) or deep brain stimulation [DBS]. These targets are: The ventral intermediate nucleus of the thalamus (Vim), the internal segment of the Globus Pallidus (GPi) and the subthalamic nucleus (STN). OBJECTIVE: To assess the outcome (3 months & 6 months) of lesioning procedures in parkinson’s disease (PD) patients meeting the inclusion criteria. METHODS: A prospective clinical study conducted on 10 IPD patients during the period from October 2018 to March 2021 at Cairo University Hospitals. This study was concerned to improve the motor symptoms of IPD patients by stereotactic radiofrequency ablative procedures. Cases were restricted to 10 patients due to the Covid-19 pandemic and restriction of elective cases for chronic patients at Cairo University hospitals. RESULTS: In our study we operated upon 10 IPD patients who were meeting our selection criteria by ablative procedures contralateral to parkinsonian symptoms. Age of the patients ranged 17 – 70y with mean of 50.5 ± 16.35 y with predominance in males representing 6 patients. Mean duration of Parkinson`s disease according to history ranged from 2 to 12 y with mean of 8 ± 3.1 years. Patients were divided into three groups according to their presentation and the operation done for them. Thalamotomy group: Pre-operatively, the UPDRS III off & on respectively was 24.4/15.2 and post-operatively was 13/7.4 with improvement 47% / 51%. The tremor subscore was 5.4/2.8 pre-operatively and 1.4/0.8 post-operatively with average of 72% improvement. The UPDRS II pre was 17.2/11.6 and post it became 10.6/7 with 39% improvement. Modified H&Y 2.4/1.7 pre & post-operatively (29% improvement). Pallidotomy group: Pre-operatively, the UPDRS III off & on respectively was 38.5/23.5 and post-operatively was 28/16 with improvement 27% / 32%. The rigidity subscore was 5/2.5 pre-operatively and 2/1 post-operatively with average of 60% improvement. The bradykinesia subscore was 9/5.5 pre-operatively and 5.5/2.5 post-operatively with average of 47% improvement. The dyskinesia subscore was 4.5 pre-operatively and 1.2 post-operatively with average of 71% improvement. The UPDRS II pre was 22/12.5 and post it became 16/10 with 25% improvement. Modified H&Y 2.75/2.25 pre & post-operatively (18% improvement). Combined group: Pre-operatively, the UPDRS III off & on respectively was 41.33/28.67 and post-operatively was 15.67/11.33 with improvement 62% /60%. The rigidity subscore was 5/3.33 pre-operatively and 1.67/1 post-operatively with average of 68% improvement. The bradykinesia subscore was 10/6 pre-operatively and 4/1.33 post-operatively with average of 72% improvement. The UPDRS II pre was 28.33/19.33 and post it became 16.33/10.67 with 43% improvement. Modified H&Y 2.83/2 pre & post-operatively (29% improvement). Postoperatively, there was a high significant statistical finding in all clinical score and subscore of parkinsonian symptoms. CONCLUSION: The study concludes that lesioning procedure should be revisited globally using the modern techniques of targeting and controlled thermal lesion protocols guided by capsular somatotopy and intraoperative macroelectrode stimulation, that will improve the outcome dramatically. Ablative procedures proved their efficacy in controlling motor symptoms of IPD and their cost-benefit in low & middle-income nations.

Effects on cognition and quality of life with unilateral magnetic resonance-guided focused ultrasound thalamotomy for essential tremor

OBJECTIVE Although neurosurgical procedures are effective treatments for controlling involuntary tremor in patients with essential tremor (ET), they can cause cognitive decline, which can affect quality of life (QOL). The purpose of this study is to assess the changes in the neuropsychological profile and QOL of patients following MR-guided focused ultrasound (MRgFUS) thalamotomy for ET. METHODS The authors prospectively analyzed 20 patients with ET who underwent unilateral MRgFUS thalamotomy at their institute in the period from March 2012 to September 2014. Patients were regularly evaluated with the Clinical Rating Scale for Tremor (CRST), neuroimaging, and cognition and QOL measures. The Seoul Neuropsychological Screening Battery was used to assess cognitive function, and the Quality of Life in Essential Tremor Questionnaire (QUEST) was used to evaluate the postoperative change in QOL. RESULTS The total CRST score improved by 67.3% (from 44.75 ± 9.57 to 14.65 ± 9.19, p < 0.001) at 1 year following MRgFUS thalamotomy. Mean tremor scores improved by 68% in the hand contralateral to the thalamotomy, but there was no significant improvement in the ipsilateral hand. Although minimal cognitive decline was observed without statistical significance, memory function was much improved (p = 0.031). The total QUEST score also showed the same trend of improving (64.16 ± 17.75 vs 27.38 ± 13.96, p < 0.001). CONCLUSIONS The authors report that MRgFUS thalamotomy had beneficial effects in terms of not only tremor control but also safety for cognitive function and QOL. Acceptable postoperative changes in cognition and much-improved QOL positively support the clinical significance of MRgFUS thalamotomy as a new, favorable surgical treatment in patients with ET.

Focused ultrasound thalamotomy in Parkinson disease: Nonmotor outcomes and quality of life

OBJECTIVE

To examine nonmotor outcomes and correlates of quality of life (QoL) 3 and 12 months after unilateral focused ultrasound thalamotomy in tremor-dominant Parkinson disease (TDPD).

METHODS

Twenty-seven patients with TDPD in a double-blind, sham-controlled, randomized clinical trial underwent comprehensive neuropsychological evaluations. These included assessment of mood, behavior, and QoL at baseline, 3 months, 3 months post crossover in the sham group, and 12 months after active treatment. We used Mann-Whitney U tests to assess differences between the active (n = 20) and sham (n = 7) groups at 3 months and Friedman tests to assess within-group changes after active treatment. We assessed correlations between disease variables and postoperative QoL using Kendall tau-b tests.

RESULTS

There were no differences in cognition, mood, or behavior between the active and sham groups at 3-month blinded assessment. After active treatment, there were no differences in mood or behavior. Only declines in Stroop Color Naming and phonemic fluency were observed. Patients experienced postoperative improvements in QoL and activities of daily living (ADL). Mood and behavioral symptoms, aspects of cognitive functioning, ADL, and overall motor symptom severity, but not tremor severity specifically, were associated with QoL.

CONCLUSIONS

In TDPD, unilateral focused ultrasound thalamotomy appears safe from a cognitive, mood, and behavioral perspective. QoL and ADL significantly improved following surgery. Nonmotor symptoms and ADL were more closely associated with QoL than tremor severity.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for patients with TDPD, unilateral focused ultrasound thalamotomy did not adversely change cognition, mood, or behavior at 3 months.

Early effect of thalamotomy on cognitive function in patients with Parkinson’s disease

Thalamotomy is a neurosurgical procedure used in the treatment of advanced Parkinson’s disease (PD). The aim of our research is to evaluate the early impact of a lesion in the ventrointermedial nucleus (VIM) of the thalamus on cognitive and motor function in people with PD. Sixty patients who qualified for right- or left-sided VIM thalamotomy were involved in the study. The cognitive and motor functions of each patient were assessed both prior to and following the surgical procedure. Twenty-nine PD patients without ablative treatment were qualified for the comparison group, and 57 neurologically healthy individuals were assigned to the control group. The following tests were carried out: Mini Mental State Examination, Benton Visual Retention Test, Stroop Color and Word Test, Trail Making Test A&B, and Rey Auditory Verbal Learning Test. Statistically significant differences were found in reaction time, visual-spatial working memory, auditory-verbal memory, and overall level of cognitive function when comparing the results of tests carried out before and after thalamotomy and when comparing patients who had undergone surgery with untreated or healthy individuals. In patients with right-sided and left-sided thalamotomy differences were also found in the mean number of perseverative errors and recalled words.

Emerging therapies for Parkinson's disease: from bench to bedside

The prevalence of Parkinson's disease (PD) increases with age and is projected to increase in parallel to the rising average age of the population. The disease can have significant health-related, social, and financial implications not only for the patient and the caregiver, but for the health care system as well. While the neuropathology of this neurodegenerative disorder is fairly well understood, its etiology remains a mystery, making it difficult to target therapy. The currently available drugs for treatment provide only symptomatic relief and do not control or prevent disease progression, and as a result patient compliance and satisfaction are low. Several emerging pharmacotherapies for PD are in different stages of clinical development. These therapies include adenosine A2A receptor antagonists, glutamate receptor antagonists, monoamine oxidase inhibitors, anti-apoptotic agents, and antioxidants such as coenzyme Q10, N-acetyl cysteine, and edaravone. Other emerging non-pharmacotherapies include viral vector gene therapy, microRNAs, transglutaminases, RTP801, stem cells and glial derived neurotrophic factor (GDNF). In addition, surgical procedures including deep brain stimulation, pallidotomy, thalamotomy and gamma knife surgery have emerged as alternative interventions for advanced PD patients who have completely utilized standard treatments and still suffer from persistent motor fluctuations. While several of these therapies hold much promise in delaying the onset of the disease and slowing its progression, more pharmacotherapies and surgical interventions need to be investigated in different stages of PD. It is hoped that these emerging therapies and surgical procedures will strengthen our clinical armamentarium for improved treatment of PD.