Combined accelerometer and genetic analysis to differentiate essential tremor from Parkinson's disease.

Essential tremor (ET) and Parkinson's disease (PD) are among the most common adult-onset tremor disorders. Clinical and pathological studies suggest that misdiagnosis of PD for ET, and vice versa, occur in anywhere from 15% to 35% of cases. Complex diagnostic procedures, such as dopamine transporter imaging, can be powerful diagnostic aids but are lengthy and expensive procedures that are not widely available. Preliminary studies suggest that monitoring of tremor characteristics with consumer grade accelerometer devices could be a more accessible approach to the discrimination of PD from ET, but these studies have been performed in well-controlled clinical settings requiring multiple maneuvers and oversight from clinical or research staff, and thus may not be representative of at-home monitoring in the community setting. Therefore, we set out to determine whether discrimination of PD vs. ET diagnosis could be achieved by monitoring research subject movements at home using consumer grade devices, and whether discrimination could be improved with the addition of genetic profiling of the type that is readily available through direct-to-consumer genetic testing services. Forty subjects with PD and 27 patients with ET were genetically profiled and had their movements characterized three-times a day for two weeks through a simple procedure meant to induce rest tremors. We found that tremor characteristics could be used to predict diagnosis status (sensitivity = 76%, specificity = 65%, area under the curve (AUC) = 0.75), but that the addition of genetic risk information, via a PD polygenic risk score, did not improve discriminatory power (sensitivity = 80%, specificity = 65%, AUC = 0.73).

Person-Centered Care in the Home Setting for Parkinson's Disease: Operation House Call Quality of Care Pilot Study.

Objective. (1) To evaluate the feasibility of implementing and evaluating a home visit program for persons with Parkinson's disease (PD) in a rural setting. (2) To have movement disorders fellows coordinate and manage health care delivery. Background. The University of Florida, Center for Movement Disorders and Neurorestoration established Operation House Call to serve patients with PD who could not otherwise afford to travel to an expert center or to pay for medical care. PD is known to lead to significant disability, frequent hospitalization, early nursing home placement, and morbidity. Methods. This was designed as a quality improvement project. Movement disorders fellows travelled to the home(s) of underserved PD patients and coordinated their clinical care. The diagnosis of Parkinson's disease was confirmed using standardized criteria, and the Unified Parkinson's Disease Rating Scale was performed and best treatment practices were delivered. Results. All seven patients have been followed up longitudinally every 3 to 6 months in the home setting, and they remain functional and independent. None of the patients have been hospitalized for PD related complications. Each patient has a new updatable electronic medical record. All Operation House Call cases are presented during video rounds for the interdisciplinary PD team to make recommendations for care (neurology, neurosurgery, neuropsychology, psychiatry, physical therapy, occupational therapy, speech therapy, and social work). One Operation House Call patient has successfully received deep brain stimulation (DBS). Conclusion. This program is a pilot program that has demonstrated that it is possible to provide person-centered care in the home setting for PD patients. This program could provide a proof of concept for the construction of a larger visiting physician or nurse program.

A genome sequencing program for novel undiagnosed diseases.

PURPOSE: The Scripps Idiopathic Diseases of Man (IDIOM) study aims to discover novel gene-disease relationships and provide molecular genetic diagnosis and treatment guidance for individuals with novel diseases using genome sequencing integrated with clinical assessment and multidisciplinary case review. Here we describe the operational protocol and initial results of the IDIOM study. METHODS: A total of 121 cases underwent first-tier review by the principal investigators to determine whether the primary inclusion criteria were satisfied, 59 (48.8%) underwent second-tier review by our clinician-scientist review panel, and 17 patients (14.0%) and their family members were enrolled. RESULTS: 60% of cases resulted in a plausible molecular diagnosis, and 18% of cases resulted in a confirmed molecular diagnosis. Two of three confirmed cases led to the identification of novel gene-disease relationships. In the third confirmed case a previously described but unrecognized disease was revealed. In all three confirmed cases a new clinical management strategy was initiated based on the genetic findings. CONCLUSION: Genome sequencing provides tangible clinical benefit for individuals with idiopathic genetic disease, not only in the context of molecular genetic diagnosis of known rare conditions but also in cases where prior clinical information regarding a new genetic disorder is lacking.

Low-frequency versus high-frequency subthalamic nucleus deep brain stimulation on postural control and gait in Parkinson's disease: a quantitative study.

BACKGROUND: High frequency stimulation (HFS) of the subthalamic nucleus (STN-DBS) has been shown to have little impact on postural control and gait improvements in Parkinson's disease (PD). There is a lack of consensus and quantitative evidence to suggest that stimulating STN at a lower frequency (LFS) as compared to HFS will be superior in improving symptoms. OBJECTIVE/HYPOTHESIS: To determine if postural control and gait characteristics of persons with PD improve at an LFS (60 Hz) compared to HFS (>100 Hz). We hypothesized that persons with PD would perform better on postural control and gait measures at LFS. METHODS: Nineteen participants with bilateral STN-DBS underwent UPDRS, static and dynamic postural control using gait initiation, and gait evaluations in three stimulation conditions (baseline voltage stable across conditions: OFF, LFS of 60 Hz, and HFS of >100 Hz). Additionally 10/19 participants were also stimulated at 30 Hz and 60 Hz and at higher voltages. A one-way ANOVA was performed to compare the conditions. RESULTS: Total UPDRS-III score, step length and velocity during gait initiation, and gait speed significantly improved during 60 Hz and >100 Hz conditions when compared to the OFF condition (P < 0.05). There were no significant differences between 60 Hz and >100 Hz conditions. Using LFS at higher voltage showed no improvement over >100 Hz condition. CONCLUSIONS: The positive effects of both LFS and HFS on postural control and gait were similar and clinical changes were relatively small. LFS may not help improve postural control, and gait particularly for persons with PD who do not develop gait-related disorders after HFS.

Selective use of low frequency stimulation in Parkinson's disease based on absence of tremor.

BACKGROUND: High frequency stimulation (HFS) of the subthalamic nucleus is one of the most effective treatments for advanced Parkinson's disease (PD). HFS has provided beneficial improvements in the cardinal features of PD, but has not been proven as effective for addressing the axial predominant levodopa resistant symptoms, such as speech disturbances, gait disturbances, and postural instability. Recent studies have suggested that changes in stimulation parameters may influence differing PD symptoms. OBJECTIVE: The purpose of this study was to compare the effects of low frequency stimulation (LFS) versus HFS on the Unified Parkinson's Disease Rating Scale (UPDRS), gait, balance, and verbal fluency. METHODS: Eight tremor dominant and nine non-tremor dominant participants with bilateral deep brain stimulation of the subthalamic nucleus were tested off stimulation, during LFS, and during HFS. RESULTS: Results revealed that HFS significantly reduced UPDRS tremor score in the tremor dominant group; however no differences emerged within the non-tremor dominant group. No differences between groups or stimulation conditions were found for gait, balance, and verbal fluency measures. CONCLUSION: These results may suggest that HFS is better than LFS for reducing tremor in tremor dominant patients. However, patients with mild or no tremor show no acute differences in benefit from LFS as compared to HFS.

Taking a better history for behavioral issues pre- and post-deep brain stimulation: issues missed by standardized scales.

OBJECTIVES: To screen for potentially underreported behavioral changes in patients with idiopathic Parkinson's disease (PD) pre- and post-deep brain stimulation (DBS), a retrospective data base review was performed. METHODS: In total, 113 patients who underwent unilateral or bilateral DBS at the University of Florida in either subthalamic nucleus or globus pallidus internus for PD were screened for behavioral issues by asking about the presence or absence of seven neuropsychiatric symptoms (panic, fear, paranoia, anger, suicidal flashes, crying, and laughing). RESULTS: There was a high prevalence of fear (16.3%), panic (14.0%), and anger (11.6%) at baseline in this cohort. In the first six months following DBS implantation, anger (32.6%), fear (26.7%), and uncontrollable crying (26.7%) were the most frequent symptoms reported. Those symptoms also were present following six months of DBS surgery (30.2%, 29.1%, and 19.8%, respectively). New uncontrollable crying occurred more in the acute postoperative stage (less than or equal to six months) (p = 0.033), while new anger occurred more in the chronic postoperative stage (greater than six months) (p = 0.017). The frequency of uncontrollable laughing significantly increased with bilateral DBS (p = 0.033). CONCLUSIONS: Many of the neuropsychiatric issues were identified at preoperative baseline and their overall occurrence was more than expected. There was a potential for worsening of these issues post-DBS. There were subtle differences in time course, and in unilateral vs. bilateral implantations. Clinicians should be aware of these potential behavioral issues that may emerge following DBS therapy, and should consider including screening questions in preoperative and postoperative interviews. Standardized scales may miss the presence or absence of these clinically relevant issues.

Improvement of both dystonia and tics with 60 Hz pallidal deep brain stimulation.

Deep brain stimulation has been utilized in both dystonia and in medication refractory Tourette syndrome. We present an interesting case of a patient with a mixture of disabling dystonia and Tourette syndrome whose coexistent dystonia and tics were successfully treated with 60 Hz-stimulation of the globus pallidus region.

Low-Frequency Deep Brain Stimulation for Dystonia: Lower is Not Always Better.

BACKGROUND: It has been observed that low-frequency stimulation (LFS) may be effective for dystonia, and the use of LFS may alleviate the need for frequent battery changes in a subset of patients. The aim of this study was to analyze LFS as a strategy to treat deep brain stimulation (DBS) patients with various dystonias. METHODS: Subjects had to receive a minimum of 6 months of clinical follow-up at the University of Florida, and were required to have a minimum of 3 months on a LFS trial. Twenty-seven dystonia DBS patients were retrospectively analyzed from the UF-INFORM database. RESULTS: Thirteen subjects met inclusion criteria. Of the 13 subjects, all had bilateral internal pallidum (GPi) DBS, and five (38.5%) remained with at least one side on LFS settings at their last follow up (average follow up 24 months, range 6-46 months). Within the first 6 months, six (46%) subjects remained on LFS and seven (54%) were changed to high-frequency stimulation (HFS). Those who remained on LFS settings at 6 months were characterized by shorter disease durations than those on HFS settings. There were no significant differences in dystonia severity (Unified Dystonia Rating Scale and Burke-Fahn-Marsden Dystonia Rating Scale) at baseline between the two settings. The estimated battery life for LFS (79.9±30.5) was significantly longer than for HFS settings (32.2±13.1, p<0.001). DISCUSSION: LFS was ultimately chosen for 38.5% of all subjects. Although this study failed to yield solid predictive features, subjects on LFS tended to have shorter disease durations.

Unilateral GPi-DBS as a treatment for levodopa-induced respiratory dyskinesia in Parkinson disease.

BACKGROUND: Respiratory dyskinesia is a rare but disabling complication of levodopa therapy for Parkinson disease; however, its treatment has been limited to medication optimization. CASE REPORT: A 72-year-old woman with a 6-year history of Parkinson disease presented with severe and debilitating levodopa-induced respiratory dyskinesia, which manifested with a short and shallow breathing pattern and panting. These symptoms were observed coincident with limb and truncal dyskinesias. Both respiratory and limb/trunk dyskinesias were addressed by the implantation of a unilateral globus pallidus interna deep brain stimulator (GPi-DBS). CONCLUSIONS: Although the mechanism of involvement of the respiratory system in dyskinesia is unknown, GPi-DBS seems to be a potentially viable treatment option for these patients.

The Frequency of Nonmotor Symptoms among Advanced Parkinson Patients May Depend on Instrument Used for Assessment.

Background. Nonmotor symptoms (NMS) of Parkinson's disease (PD) may be more debilitating than motor symptoms. The purpose of this study was to determine the frequency and corecognition of NMS among our advanced PD cohort (patients considered for deep brain stimulation (DBS)) and caregivers. Methods. NMS-Questionnaire (NMS-Q), a self-administered screening questionnaire, and NMS Assessment-Scale (NMS-S), a clinician-administered scale, were administered to PD patients and caregivers. Results. We enrolled 33 PD patients (23 males, 10 females) and caregivers. The most frequent NMS among patients using NMS-Q were gastrointestinal (87.9%), sleep (84.9%), and urinary (72.7%), while the most frequent symptoms using NMS-S were sleep (90.9%), gastrointestinal (75.8%), and mood (75.8%). Patient/caregiver scoring correlations for NMS-Q and NMS-S were 0.670 (P < 0.0001) and 0.527 (P = 0.0016), respectively. Conclusion The frequency of NMS among advanced PD patients and correlation between patients and caregivers varied with the instrument used. The overall correlation between patient and caregiver was greater with NMS-Q than NMS-S.

Mixed results for GPi-DBS in the treatment of cranio-facial and cranio-cervical dystonia symptoms.

The aim of the study is to determine clinical outcomes in patients undergoing Globus Pallidus Internus Deep Brain Stimulation (GPi-DBS) for cranio-facial and cranio-cervical dystonia (Meige) symptoms. A total of 6 patients seen between 2002 and 2010 with cranio-facial and cranio-cervical dystonia symptoms were identified from the University of Florida Institutional Review Board approved database. Patients were videotaped using a standardized protocol, and tapes were randomized and blindly reviewed by a movement disorders neurologist. The Unified Dystonia Rating Scale improved 31.6 ± 23.2% (range: 3.4-63.2%) at 6 months and 63.7 ± 35.3% (range: 6.3-100%) at 12 months. The Burke-Fahn-Marsden Dystonia Rating Scale improved 45.3 ± 29.5% (range: 4.7-75.0%) at 6 months and 61.8 ± 30.9% (range: 16.6-100%) at 12 months. One patient significantly had a very large improvement with little evidence of residual dystonia. Blepharospasm improved in all patients, whereas speech and swallowing did not improve in this cohort. Two patients improved with unilateral GPi-DBS, although one required a contralateral DBS later in the disease course. Two patients were managed with low frequency stimulation (<100 Hz). Two patients had less than 20% benefit. GPi-DBS for cranio-facial and cranio-cervical symptoms is an effective strategy to manage a subset of patients who remain unresponsive to optimized medical management. Unilateral stimulation may be an option for some patients, but it remains unclear whether response to single-sided stimulation will be sustainable. The mixed results of this GPi-DBS case series highlight the need for a careful re-examination of selection criteria, alternative brain targets, and possibly rescue leads for patients who are non-responders to the GPi target.

Rescue leads: a salvage technique for selected patients with a suboptimal response to standard DBS therapy.

OBJECT: We present four cases where supplementary "rescue" deep brain stimulation (DBS) leads were added for patients who failed to obtain anticipated clinical benefits. METHODS: Nine patients out of 295 patients who underwent DBS between 2002 and 2009, were identified as rescue lead recipients. Of these nine cases, four cases were evaluated. Two had medication refractory tremor which was incompletely suppressed by Vim (nucleus ventralis intermedius) thalamic DBS, and supplemental rescue leads were implanted in either the VO (ventral oralis) thalamic nucleus or the STN (subthalamic nucleus). The remaining two cases were patients with severe dystonia who were initially treated with bilateral GPi (globus pallidus internus)-DBS, and following suboptimal clinical benefits, a second GPi rescue lead was added in a case, and bilateral STN rescue leads were added in the other case. Outcomes of scores collected included Fahn-Tolosa-Marin Tremor Rating Scale (TRS) for tremor cases and the Unified Dystonia Rating Scale (UDRS) for dystonia cases and the symptom specific patient global impression scales (PGIS; 7 point scale). RESULTS: In the tremor cases, the TRS scale improved by 34.1 ± 7.4% and the PGIS following rescue lead was "minimally improved" to "very much improved" (range 1-2). In dystonia cases, the UDRS improved by 50.0 ± 23.6% and the PGIS was "minimally improved" to "very much improved" (range 1-2) after rescue lead surgery. CONCLUSION: This small retrospective case series demonstrated that, in appropriately selected patients with suboptimal results of standard DBS therapy, the addition of rescue lead(s) may provide meaningful clinical benefit.

Two McLeod patients with novel mutations in XK.

McLeod syndrome (MLS) is a rare, X-linked, late-onset, disease involving hematological, brain, and neuromuscular systems, caused by mutations in XK that result in either defective XK or complete loss of XK protein. Acanthocytosis of erythrocytes is a typical feature. We report novel mutations in two patients who exhibited typical clinical characteristics of MLS. The coding and flanking intronic regions of XK were amplified by PCR, sequenced, and compared with the normal XK sequence. XK protein, and its complexed partner protein, Kell, were assessed by Western blot analysis. Patient 1 was found to have a single base insertion, 605insA at 175Ile creating a frame shift within the coding sequence of XK. Patient 2 had a single base substitution in the 3' splice sequence of intron 2 (IVS2-2a>g). In both cases mutations resulted in the absence of XK protein.

Steady or not following thalamic deep brain stimulation for essential tremor.

Deep brain stimulation (DBS) has become an important option for medication-refractory essential tremor (ET), but may contribute to worsened gait and falling. This study evaluates impaired gait in a cohort of patients treated with DBS with a retrospective review of ET patients before and after DBS implantation. Factors examined included: age, duration of symptoms, pre-morbid gait difficulties/falls, Fahn-Tolosa-Marin tremorrating scale (TRS) scores at baseline, 6 months post-unilateral DBS implantation, and 6 or 12 months post-bilateral implantation. All implantations targeted the nucleus ventralis intermediate (Vim). Thirty-eight patients (25 males, 13 females) were included. Twenty-five patients (65.8%) underwent unilateral DBS implantation and 13 (34.2%) bilateral. The mean age at surgery was 67.1 years ± 11.4 (range 34-81). The mean disease duration was 31 years ± 18.3 (range 6-67). Fifty-eight percent of patients had worsened gait post-operatively. Seventy percent of patients with unilateral Vim DBS experienced gait worsening while 55% of bilateral DBS patients experienced gait worsening. Patients with worsened gait post-DBS had higher baseline pre-operative TRS scores than those without worsened gait (43.1 points ± 8.4 vs. 33.1 points ± 10.1, p = 0.002) (odds ratio 2.5, p = 0.02). Gait/balance may worsen following DBS for medication refractory ET. Higher baseline TRS score may factor into these issues, although a larger prospective study will be required with a control population. The larger percentage of difficulties observed in unilateral versus bilateral cases likely reflected the bias not to proceed to second-sided surgery if gait/balance problems were encountered.

Botulinum toxin type A for the treatment of gastroparesis in Parkinson's disease patients.

Gastroparesis is a very common non-motor feature in Parkinson's disease (PD) patients. However, treatment options are limited and difficult. We present 2 cases of PD patients with excellent response to botulinum toxin type A as treatment for PD-related gastroparesis.

Effect of Deep Brain Stimulation on Parkinson's Nonmotor Symptoms following Unilateral DBS: A Pilot Study.

Parkinson's disease (PD) management has traditionally focused largely on motor symptoms. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus internus (GPi) are effective treatments for motor symptoms. Nonmotor symptoms (NMSs) may also profoundly affect the quality of life. The purpose of this pilot study was to evaluate NMS changes pre- and post-DBS utilizing two recently developed questionnaires. Methods. NMS-Q (questionnaire) and NMS-S (scale) were administered to PD patients before/after unilateral DBS (STN/GPi targets). Results. Ten PD patients (9 STN implants, 1 GPi implant) were included. The three most frequent NMS symptoms identified utilizing NMS-Q in pre-surgical patients were gastrointestinal (100%), sleep (100%), and urinary (90%). NMS sleep subscore significantly decreased (-1.6 points ± 1.8, P = 0.03). The three most frequent NMS symptoms identified in pre-surgical patients using NMS-S were gastrointestinal (90%), mood (80%), and cardiovascular (80%). The largest mean decrease of NMS scores was seen in miscellaneous symptoms (pain, anosmia, weight change, and sweating) (-7 points ± 8.7), and cardiovascular/falls (-1.9, P = 0.02). Conclusion. Non-motor symptoms improved on two separate questionnaires following unilateral DBS for PD. Future studies are needed to confirm these findings and determine their clinical significance as well as to examine the strengths/weaknesses of each questionnaire/scale.

Tests of dorsolateral frontal function correlate with objective tests of postural stability in early to moderate stage Parkinson's disease.

A substantial number of individuals with Parkinson's disease who display impaired postural stability experience accelerated cognitive decline and an increased prevalence of dementia. To date, studies suggest that this relationship, believed to be due to involvement of nondopaminergic circuitry, occurs later in the disease process. Research has yet to adequately investigate this cognitive-posturomotor relationship especially when examining earlier disease states. To gain greater understanding of the relationship between postural stability and cognitive function/dysfunction we evaluated a more stringent, objective measure of postural stability (center of pressure displacement), and also more specific measures of cognition in twenty-two patients with early to moderate stage Parkinson's disease. The magnitude of the center of pressure displacement in this cohort was negatively correlated with performance on tests known to activate dorsolateral frontal regions. Additionally, the postural stability item of the UPDRS exhibited poor correlation with the more objective measure of center of pressure displacement and all specific measures of cognition. These results may serve as rationale for a more thorough evaluation of postural stability and cognition especially in individuals with mild Parkinson's disease. Greater understanding of the relationship between motor and cognitive processes in Parkinson's disease will be critical for understanding the disease process and its potential therapeutic possibilities.

Differential response of dystonia and parkinsonism following globus pallidus internus deep brain stimulation in X-linked dystonia-parkinsonism (Lubag).

BACKGROUND: X-linked dystonia-parkinsonism (XDP; DYT3; Lubag) is an adult-onset hereditary progressive dystonia/parkinsonism which is typically minimally responsive to pharmacological treatment. CASE REPORT: We report a 63- year-old man with a diagnosis of XDP who underwent bilateral globus pallidus internus deep brain stimulator (GPi-DBS) placement. His course initially began with right hand tremor and dystonia at age 57 and progressed to also include bradykinesia and rigidity. The patient tolerated the procedure without significant complications. GPi-DBS improved his right hand dystonia, but did not significantly improve his parkinsonism. CONCLUSION: DBS may be a therapeutic option for select cases of XDP, but its specific indications must be carefully discussed, as the available cases have had mixed responses. Whether other targets may be more effective is not known.

Update on deep brain stimulation for neuropsychiatric disorders.

Deep brain stimulation (DBS) has proven a powerful treatment for medication refractory movement disorders. Success in this group of patients has allowed preliminary studies of DBS to proceed in severe and medication resistant cases of depression, obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS). Pathophysiological and imaging studies along with attempts at lesioning the basal ganglia, have offered clues as to nodes in the circuitry that may be amenable to neuromodulation. DBS in neuropsychiatric illness has offered hope, but at this time rigorous screening by interdisciplinary and ethical teams should be employed when establishing treatment candidacy. A cautious approach to these disorders utilizing institutional review board approved research protocols will hopefully shed light onto patient selection and brain target(s) for each disorder. We need to keep an open mind as we move forward and especially that rational therapy may need to be patient and symptom specific. This review will summarize each disorder (depression, OCD and TS), review pathophysiology (both known and speculated), and update the current observations on DBS in each neuropsychiatric condition.