Kathrin LaFaver

Loss of benefit in VIM thalamic deep brain stimulation (DBS) for essential tremor (ET): how prevalent is it?

Ventralis intermedius (Vim) thalamic deep brain stimulation for medication-refractory essential tremor (ET) has been shown to significantly improve severity of limb tremor in several large case series with significant reduction in objective motor scores. A variable proportion of patients experience decline in benefit over time, however, most studies have not been designed to describe the phenomenon of waning benefit in terms that are helpful for patient counseling. In this retrospective single center study, we define waning benefit as a phenomenon that occurs after patients begin to require reprogramming visits to optimize DBS benefit on tremor. We employed a survival analysis with time to escape (TTE) as a quantitative measure of time elapsed between implantation and the need for subsequent reprogramming. In our cohort of ET patients operated on with Vim DBS from 1994 to 2009, among 45 subjects who met inclusion criteria, 73% reported waning benefit at some point during a mean follow-up period of 56 months (range 12-152 months). The mean TTE from implantation date was 18 months (range 3-75 months). We conclude that loss of benefit over time from Vim DBS for ET is more prevalent than previously published estimates have indicated and should be discussed during patient counseling regarding durability of expected benefit. In addition, this data suggests that a disease-based explanation rather than technical factors are more likely to explain the decline in benefit.

Personality traits in psychogenic nonepileptic seizures (PNES) and psychogenic movement disorder (PMD): Neuroticism and perfectionism

OBJECTIVE Psychogenic movement disorder (PMD) and psychogenic nonepileptic seizures (PNES) are two subtypes of conversion disorder (CD). In this case-control study, we asked whether these subtypes varied as a function of personality and history of childhood abuse. METHODS Fifty-nine patients with PMD from the Human Motor Control Section Clinic at the National Institutes of Health, 43 patients with PNES from the Rhode Island Hospital Neuropsychiatry and Behavioral Neurology Division, and 26 healthy volunteers (HC) received a battery of neurological, psychiatric and psychological assessments, including the NEO Personality Inventory Revised (NEO PI-R), the Childhood Trauma Questionnaire (CTQ), and the Traumatic Life Events Questionnaire (TLEQ). RESULTS One-way ANOVA between the three groups indicated significant differences in overall domains of Neuroticism (p=0.001) and Conscientiousness (p=0.009): Patients with PNES reported significantly greater levels of Neuroticism (p=0.002) and lower levels of Conscientiousness (p=0.023) than patients with PMD. Levels of Neuroticism remained significantly higher in both PMD and PNES than HC following correction for multiple comparisons. Patients with PNES reported greater levels of depressive and anxiety symptoms, overall psychopathology, greater history of sexual abuse, greater levels of alexithymia, higher levels of dissociative symptoms, and an earlier age at which they experienced their most distressing traumatic event than patients with PMD. CONCLUSIONS These findings suggest that personality traits, type of abuse and age of onset of trauma varies as a function of CD subtype. Patients with PNES rated greater Neuroticism and lower Conscientiousness than patients with PMD. These differing psychological profiles may inform differing treatment approaches such as psychological therapies for PNES and physiotherapy (with/without psychotherapy) for PMD.

Functional or psychogenic: what's the better name?

tional’ is that it might imply normal function rather than dysfunction and contradicts the notion that the treating physician wants and should convey to the patient about the ‘cause’ of the psychogenic disorder.” These are some of the reasons why I still prefer the term psychogenic instead of functional. Patients who present with these disorders generally perceive themselves as “dysfunctional” rather than “functional.” Furthermore, I believe that the latter term is too vague. When the term psychogenic is introduced to the patients in a sensitive and tactful way and the patients are reassured that there is no evidence of “neurological damage,” they are more willing to accept the role of psychodynamic factors, such as stress, in their condition and are more amenable to psychological and psychiatric intervention. Most patients understand that stress can cause elevation in blood pressure, palpitation, and tremors, so they can also accept that dystonia, parkinsonism, tics, and other movement disorders can be manifestations of stress or other psychological factors, even though these precipitants may not always be obvious or readily identifiable, especially during the first encounter.

Chapter 51 – Inpatient treatment for functional neurologic disorders

Patients with functional neurologic disorders present to clinicians with a variety of symptomatic manifestations, with various levels of severity, chronicity, and comorbidity, as well as with various degrees of past adversity, intrinsic resilience, and available external support. Clearly, treatment must be individualized. For those patients who have been severely or chronically impaired, especially if adequate prior outpatient treatments have failed, inpatient treatment that integrates the various modalities outlined here provides a rational route of rescue from a course otherwise potentially characterized by protracted dependence and disability. Based on the data currently available, we believe this treatment approach is worthy of further study to refine the component treatment strategies and enhance the potentially most effective ingredients. For patients with severe levels of disability, who could be managed in a multimodal day-treatment program, that approach also warrants further consideration.

Functional neurological disorders in Parkinson disease

Objective To ascertain demographic and clinical features of Parkinson disease (PD) associated with functional neurological features. Methods A standardised form was used to extract data from electronic records of 53 PD patients with associated functional neurological disorders (PD-FND) across eight movement disorders centres in the USA, Canada and Europe. These subjects were matched for age, gender and disease duration to PD patients without functional features (PD-only). Logistic regression analysis was used to compare both groups after adjusting for clustering effect. Results Functional symptoms preceded or co-occurred with PD onset in 34% of cases, nearly always in the most affected body side. Compared with PD-only subjects, PD-FND were predominantly female (68%), had longer delay to PD diagnosis, greater prevalence of dyskinesia (42% vs 18%; P=0.023), worse depression and anxiety (P=0.033 and 0.025, respectively), higher levodopa-equivalent daily dose (972±701 vs 741±559 mg; P=0.029) and lower motor severity (P=0.019). These patients also exhibited greater healthcare resource utilisation, higher use of [(123)I]FP-CIT SPECT and were more likely to have had a pre-existing psychiatric disorder (P=0.008) and family history of PD (P=0.036). Conclusions A subtype of PD with functional neurological features is familial in one-fourth of cases and associated with more psychiatric than motor disability and greater use of diagnostic and healthcare resources than those without functional features. Functional manifestations may be prodromal to PD in one-third of patients.

Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders.

Importance Functional neurological disorders (FND) are common sources of disability in medicine. Patients have often been misdiagnosed, correctly diagnosed after lengthy delays, and/or subjected to poorly delivered diagnoses that prevent diagnostic understanding and lead to inappropriate treatments, iatrogenic harm, unnecessary and costly evaluations, and poor outcomes. Observations Functional Neurological Symptom Disorder/Conversion Disorder was adopted by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, replacing the term psychogenic with functional and removing the criterion of psychological stress as a prerequisite for FND. A diagnosis can now be made in an inclusionary manner by identifying neurological signs that are specific to FNDs without reliance on presence or absence of psychological stressors or suggestive historical clues. The new model highlights a wider range of past sensitizing events, such as physical trauma, medical illness, or physiological/psychophysiological events. In this model, strong ideas and expectations about these events correlate with abnormal predictions of sensory data and body-focused attention. Neurobiological abnormalities include hypoactivation of the supplementary motor area and relative disconnection with areas that select or inhibit movements and are associated with a sense of agency. Promising evidence has accumulated for the benefit of specific physical rehabilitation and psychological interventions alone or in combination, but clinical trial evidence remains limited. Conclusions and Relevance Functional neurological disorders are a neglected but potentially reversible source of disability. Further research is needed to determine the dose and duration of various interventions, the value of combination treatments and multidisciplinary therapy, and the therapeutic modality best suited for each patient.

Motor Retraining (MoRe) for Functional Movement Disorders: Outcomes From a 1-Week Multidisciplinary Rehabilitation Program

Functional movement disorders (FMDs) are conditions of abnormal motor control thought to be caused by psychological factors. These disorders are commonly seen in neurologic practice, and prognosis is often poor. No consensus treatment guidelines have been established; however, the role of physical therapy in addition to psychotherapy has increasingly been recognized. This study reports patient outcomes from a multidisciplinary FMD treatment program using motor retraining (MoRe) strategies.

Clinical Reasoning: A 28-year-old woman with lower extremity spasticity and microcytic anemia

A 28-year-old woman with a medical history of asthma, diabetes, and morbid obesity broke her right leg 3 years prior to presentation related to slipping on icy ground. She underwent surgical intervention for a tibial fracture, followed by a lengthy rehabilitation process. She never regained her previous walking ability and in fact felt that her balance was worsening. She stumbled frequently, tripping over small obstacles or uneven ground, and had 3 falls over 6 months prior to presentation. She had lost about 100 pounds after a gastric banding procedure done shortly before her accident. She denied weakness or clumsiness in upper extremities, headaches, vertigo, lightheadedness, or loss of consciousness. There was no history of fever, chills, autoimmune disorders, skin rash, joint pain or swellings, blood clots, or miscarriages. No relevant family history of neurologic disorders was present. On examination, she was noted to have a right foot drop, increased tone and hyperreflexia in lower extremities with a positive Babinski sign, and several beats of ankle clonus bilaterally. Her gait was slightly wide-based and unsteady and she had difficulties with tandem gait. Higher cognitive functions, speech, oculomotor examination, strength in upper extremities and the left leg, and sensory examination including pinprick, light touch, temperature, vibration, and proprioception was normal. She had normal coordination in upper extremities and mild difficulties with heel to shin testing bilaterally related to spasticity.

Thalamic and subthalamic deep brain stimulation for parkinsonian tremor: Are two circuits involved?

Patients with disabling, medication refractory parkinsonian tremor are excellent candidates for DBS. Although both ventral intermedialis (Vim) thalamic and STN nuclei are appropriate DBS targets for parkinsonian tremor, there are little data to support whether one target offers superior tremor suppression to the other, although presence of rigidity or bradykinesia favors STN DBS. Zona incerta DBS has also been proposed for effective tremor suppression, but lack of welldefined intraoperative neurophysiological characteristics may make lead placement challenging. We report on a patient with severe parkinsonian tremor who required simultaneous Vim and STN DBS after failing Vim or STN stimulation alone, supporting the concept of both pallidothalamocortical and cerebellothalamocortical circuits being involved in the initiation and maintenance of parkinsonian tremor. A 48-year-old man presented with gradual onset, medication refractory, left upper limb action tremor interfering with activities of daily living. Examination revealed 3to 5-cm amplitude left upper limb postural tremor with proximal involvement, mild action tremor, and absence of rest tremor. After 4 years, he developed left-sided rest tremor, hand and arm more than leg, in addition to the original postural/action tremor. Examination revealed a 4to 6-Hz, 3to 5-cm amplitude rest and postural tremor in the left hand and a 1to 2-cm amplitude rest tremor in the left leg with ipsilateral mild rigidity and bradykinesia. While walking, left arm swing was reduced with amplification of left hand tremor. Off medication, UPDRS motor score was 13, nine points because of tremor. After undergoing right Vim DBS lead implantation, despite stimulation in monopolar and bipolar settings at high amplitudes, tremor control was suboptimal and transient. Postoperative imaging confirmed the lead was optimally placed without evidence of lead migration (Fig. 1). Because of suboptimal tremor control, the patient underwent right STN lead placement (Fig. 1). STN stimulation alone (Vim DBS off), using either monopolar or bipolar settings, resulted in suboptimal tremor control. However, combined Vim and STN stimulation resulted in 100% reduction in both rest and postural/action limb tremor scores with an improvement of UPDRS motor score from 19 to 3 (see Video). Fifteen months into combined Vim and STN stimulation, the patient’s tremor remains well controlled. This patient with severe parkinsonian tremor experienced marked, durable benefit from simultaneous Vim and STN DBS, supporting the concept of a rescue lead for breakthrough or uncontrolled symptoms, especially where more than one phenomenon may overlap with another or when severity of symptoms require stimulation of a wider area of somatotopic organization. To our knowledge, this is the first published observation of simultaneous Vim and STN DBS for parkinsonian tremor. Based on the literature, reports are suggestive of complex interactions between pallidothalamocortical and cerebellothalamocortical pathways in parkinsonian tremor. Helmich et al. suggest a “dimmer-switch” model of parkinsonian tremor, such that pallidal dysfunction resulting from dopaminergic denervation triggers activity in the cerebellothalamocortical circuit, which, in turn, modulates tremor severity and amplitude. Stimulation of both STN and Vim may result in durable tremor control by suppressing both the trigger and modulatory mechanisms in cases of severe parkinsonian tremor.