Natasha Hulse

Cognitive predictors of cognitive change following bilateral subthalamic nucleus deep brain stimulation in Parkinson’s disease

The beneficial effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for the motor symptoms in advanced Parkinsons disease (PD) are well established. Early in PD, mild cognitive impairment is present in a proportion of patients. Hence, it can also be present in PD patients considered for DBS. The potential impact of even a modest decline post-surgically is a concern because it could result in impaired cognitive function. Therefore, attempts to determine which pre-operative cognitive measures predict post-operative cognitive change warrant further attention. We report our findings in a cohort of 30 routinely operated non-demented patients who underwent detailed neuropsychological assessments on average 7.1 months before and 9.4 months after STN DBS. We report the individual and group differences pre- and post-DBS. Stepwise regression analysis was used to analyse the best cognitive predictors of post-operative cognitive changes. We describe our data in relation to published normative data. Post-STN DBS, the immediate story recall component of verbal memory was the most affected cognitive function showing a significant decline in its group mean with a large effect size. The best predictors for this change were pre-surgical list learning and Full Scale Intelligence Quotient. These results suggest that non-demented patients, with even mild impairments in both general intellectual functions and list learning, may be at greater risk of decline in other aspects of verbal memory after STN DBS. Pre-existing mild executive dysfunction was not influenced post-operatively. These findings may help selection and consent for STN DBS.

Subcortical Structure Volumes and Correlation to Clinical Variables in Parkinson's Disease

MRI studies in Parkinsons Disease have shown volumetric reductions of subcortical structures such as the thalamus, putamen, globus pallidus, and caudate nucleus. However, there are no studies which look at the relationship between subcortical structure volumes and clinical variables, such as age and motor severity scores.

Shielded Battery Syndrome: A New Hardware Complication of Deep Brain Stimulation

Background: Deep brain stimulation hardware is constantly advancing. The last few years have seen the introduction of rechargeable cell technology into the implanted pulse generator design, allowing for longer battery life and fewer replacement operations. The Medtronic® system requires an additional pocket adaptor when revising a non-rechargeable battery such as their Kinetra® to their rechargeable Activa® RC. This additional hardware item can, if it migrates superficially, become an impediment to the recharging of the battery and negate the intended technological advance. Aim: To report the emergence of the ‘shielded battery syndrome’, which has not been previously described. Methods: We reviewed our deep brain stimulation database to identify cases of recharging difficulties reported by patients with Activa RC implanted pulse generators. Results: Two cases of shielded battery syndrome were identified. The first required surgery to reposition the adaptor to the deep aspect of the subcutaneous pocket. In the second case, it was possible to perform external manual manipulation to restore the adaptor to its original position deep to the battery. Conclusions: We describe strategies to minimise the occurrence of the shielded battery syndrome and advise vigilance in all patients who experience difficulty with recharging after replacement surgery of this type for the implanted pulse generator.

Pathological crying after subthalamic nucleus stimulation

Department of Clinical Neuroscience, Institute of Psychiatry, King’s College London, United Kingdom Department of Psychological Medicine, King’s College Hospital, South London and Maudsley National Health Service Foundation Trust, London, United Kingdom Department of Psychiatry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand Department of Neurology, King’s College Hospital National Health Service Foundation Trust, London, United Kingdom Department of Cognitive Neuropsychiatry, Institute of Psychiatry, London, United Kingdom Department of Neurosurgery, King’s College Hospital National Health Service Foundation Trust, London, United Kingdom Department of Neuropsychology, King’s College Hospital National Health Service Foundation Trust, London, United Kingdom

Long-Term Efficacy of Constant Current Deep Brain Stimulation in Essential Tremor: CONSTANT CURRENT DBS IN ESSENTIAL TREMOR

Ventralis intermedius deep brain stimulation is an established intervention for medication‐refractory essential tremor. Newer constant current stimulation technology offers theoretical advantage over the traditional constant voltage systems in terms of delivering a more biologically stable therapy. There are no previous reports on the outcomes of constant current deep brain stimulation in the treatment of essential tremor. This study aimed to evaluate the long‐term efficacy of ventralis intermedius constant current deep brain stimulation in patients diagnosed with essential tremor.

Verbal Memory Decline following DBS for Parkinson’s Disease: Structural Volumetric MRI Relationships

Background Parkinson’s disease is a chronic degenerative movement disorder. The mainstay of treatment is medical. In certain patients Deep Brain Stimulation (DBS) may be offered. However, DBS has been associated with post-operative neuropsychology changes, especially in verbal memory. Objectives Firstly, to determine if pre-surgical thalamic and hippocampal volumes were related to verbal memory changes following DBS. Secondly, to determine if clinical factors such as age, duration of symptoms or motor severity (UPDRS Part III score) were related to verbal memory changes. Methods A consecutive group of 40 patients undergoing bilateral Subthalamic Nucleus (STN)-DBS for PD were selected. Brain MRI data was acquired, pre-processed and structural volumetric data was extracted using FSL. Verbal memory test scores for pre- and post-STN-DBS surgery were recorded. Linear regression was used to investigate the relationship between score change and structural volumetric data. Results A significant relationship was demonstrated between change in List Learning test score and thalamic (left, p = 0.02) and hippocampal (left, p = 0.02 and right p = 0.03) volumes. Duration of symptoms was also associated with List Learning score change (p = 0.02 to 0.03). Conclusion Verbal memory score changes appear to have a relationship to pre-surgical MRI structural volumetric data. The findings of this study provide a basis for further research into the use of pre-surgical MRI to counsel PD patients regarding post-surgical verbal memory changes.

Letter to the editor: Automated night-time deep brain stimulation battery checks can induce symptoms: Identification and management of a new hardware complication

• Deep brain stimulation systems have automated IPG check times which can lead to transient rebound of disabling symptoms like tremor at time-locked intervals and present hereby a new hardware related complication.

GPi deep brain stimulation for palliation of hemidystonia and hemibody jerking in a patient with suspected adult onset neuronal ceroid lipofuscinosis

Neuronal ceroid lipofuscinoses (NCL) are inherited neurometabolic disorders which present in infants, adolescents or adults. The adult forms, which present with seizures, spasticity, visual symptoms and movement disorders, are genetically heterogeneous and can be clinically and histologically challenging to diagnose and manage [1]. Here we present one such clinical scenario. A 48 year old previously healthy woman presented with a 6 month history of progressive stiffness of the right leg. An unclassified neuropathy was reported in her mother. Brain and spinal MRI, CSF analysis