During the “DBS Canada Day” symposium held in Toronto July 4-5, 2014, the scientific committee invited experts to discuss three main questions on target selection for deep brain stimulation (DBS) of patients with Parkinson’s disease (PD). First, is the subthalamic nucleus (STN) or the globus pallidus internus (GPi) the ideal target? In summary, both targets are equally effective in improving the motor symptoms of PD. STN allows a greater medications reduction, while GPi exerts a direct antidyskinetic effect. Second, are there further potential targets? Ventral intermediate nucleus DBS has significant long-term benefit for tremor control but insufficiently addresses other motor features of PD. DBS in the posterior subthalamic area also reduces tremor. The pedunculopontine nucleus remains an investigational target. Third, should DBS for PD be performed unilaterally, bilaterally or staged? Unilateral STN DBS can be proposed to asymmetric patients. There is no evidence that a staged bilateral approach reduces the incidence of DBS-related adverse events.

Background: Psychogenic movement disorders (PMD) is a group of disorders that cannot be attributed to any structural or biochemical abnormality, but has an underlying psychiatric illness. The profile of PMD varies according to country and socioeconomic factors. Methods: The present study reports the clinical profile of patients with PMD from India. Seventy-three patients with documented or clinically established PMD were seen over a period of 14 years with detailed neurological and psychiatric examinations. Results: The mean age at presentation was 29.1±15.1 years (women, 51%). Approximately 30% were ≤18 years of age (boys, 63.6%). The onset of symptoms was abrupt in 61.6% and the initial body part most often affected was right upper limb (adults, 29.4%; children, 31.8%). Tremor was observed in 31.4% of adults and 9% of children, whereas myoclonus was more common in children (36.4%). Tremors were more often seen in women (42.3%) than in men (20%), whereas myoclonus was almost equally prevalent in girls (37.5%) and boys (35.7%). Depression was the most common psychiatric comorbidity (men, 16%; women, 15.4%). About 42.5% required hospital admission and 57.5% had significant reduction or complete cessation of PMD after counseling, antidepressants, and/ or placebo. Conclusions: PMD was equally prevalent among women and men. Tremor was most often observed in adults, whereas myoclonus was most often observed in children. Electrophysiology and placebo were useful supplementary tools for diagnosing PMD.

Akathisia is one of the most vexing problems in neuropsychiatry. Although it is one of the most common side effects of antipsychotic medications, it is often difficult to describe by patients, and is difficult to diagnose and treat by practitioners. Akathisia is usually grouped with extrapyramidal movement disorders (ie, movement disorders that originate outside the pyramidal or corticospinal tracts and generally involve the basal ganglia). Yet, it can present as a purely subjective clinical complaint, without overt movement abnormalities. It has been subtyped into acute, subacute, chronic, tardive, withdrawal-related, and “pseudo” forms, although the distinction between many of these is unclear. It is therefore not surprising that akathisia is generally either underdiagnosed or misdiagnosed, which is a serious problem because it can lead to such adverse outcomes as poor adherence to medications, exacerbation of psychiatric symptoms, and, in some cases, aggression, violence, and suicide. In this article, we will attempt to address some of the confusion surrounding the condition, its relationship to other disorders, and differential diagnosis, as well as treatment alternatives.

Cognitive loading aggravates the freezing of gait (FoG), which is observed in approximately 50% of patients with Parkinson’s disease (PD) in the advanced stages. To investigate whether a specific pattern of executive deficits, that is, attentional set-shifting and/or inhibitory control, are associated with FoG in PD, 30 PD patients with FoG (PD-FoG+) and 36 PD patients without FoG (PD-FoG−) and 22 control healthy subjects were examined with a comprehensive neuropsychological battery. Intra-Extra Dimensional Set shifting Test (IED) and Stop Signal Task (SST), selected from the Cambridge Automated Neuropsychological Battery (CANTAB battery), were administered to analyze set-shifting and motor inhibition, respectively. The IED task was significantly sensitive for differentiating between PD-FoG+ and PD-FoG− groups (p<.01), as well Adenbrook’s clock drawing task (p=.033). By contrast, no differences emerged on any aspect of the SST task and other cognitive tasks. The attrition rate during the IED task showed that the problem in the PD-FoG+ group appeared at the pre-ID level, on the discrimination-learning set; the 32% PD-FoG+ subjects did not achieve the ID level of the task in comparison to negligible 4% of the PD-FoG− patients (p=.011). The logistic regression analysis, indicated the higher the IED stage successfully completed, the less likely presence of FoG in PD subjects. These results demonstrate that the complex cognitive–motor interplay might be responsible for FoG in PD and have had real life implication for the patients. (JINS, 2014, 20, 1–8)

In the light of the recent publication of the DSM-5, there is renewed debate about the relative merit of categorical diagnosis, as laid down in Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD) diagnostic manuals. Issues such as validity, usefulness and acceptability of the diagnoses in this manual are increasingly debated. Several alternative possibilities have been suggested including: (i) the introduction of truly cross-cutting dimensional measures, that would facilitate dynamic multidimensional formulations of psychopathology, (ii) the Research Domain Criteria, that may facilitate biological research but move away from clinical symptoms, (iii) a system of personalized diagnosis based on psychopathology as a network of symptoms and contexts, and (iv) enhanced focus on motor alterations, other than catatonia, as a possible additional informative dimension of diagnosis in psychiatry, particularly as a possible marker of underlying neurodevelopmental alterations. We suggest that novel systems of diagnosis are likely to rely more on continuous monitoring of diagnostically relevant information in daily life, complementing retrospective symptom criteria in DSM and ICD. Patients and their families are likely to benefit from these projects, as novel models of diagnosis based on daily life information may be linked more strongly to treatment needs and prognosis.

Considerable evidence from preclinical and clinical investigations implicates disturbances of brain dopamine (DA) function in the pathophysiology of several psychiatric and neurologic disorders. We describe a neural model that may help organize theseindependent experimental observations. Cortical regions classically associated with the limbic system interact with infracortical structures, including the nucleus accumbens, ventral pallidum, and dorsomedial nucleus of the thalamus. In our model, overactivity in forebrain DA systems results in the loss of lateral inhibitory interactions in the nucleus accumbens, causing disinhibition of pallidothalamic efferents; this in turn causes rapid changes and a loss of focused corticothalamic activity in cortical regions controlling cognitive and emotional processes. These effects might be manifested clinically by some symptoms of psychoses. Underactivity of forebrain DA results in excess lateral inhibition in the nucleus accumbens, causing tonic inhibition of pallidothalamic efferents; this perpetuates tonic corticothalamic activity and prevents the initiation of new activity in other critical cortical regions. These effects might be manifested clinically by some symptoms of depression. This model parallels existing explanations for the etiology of several movement disorders, and may lead to testable inferences regarding the neural substrates of specific psychopathologies.

Neurodevelopmental disorders such as spina bifida meningomyelocele (SBM) are often associated with dysrhythmic movement. We studied rhythm discrimination in 21 children with SBM and in 21 age-matched controls, with the research question being whether both groups showed a strong-meter advantage whereby rhythm discrimination is better for rhythms with a strong-meter, in which onsets of longer intervals occurred on the beat, than those with a weak-meter, in which onsets of longer intervals occurred off the beat. Compared to controls, the SBM group was less able to discriminate strong-meter rhythms, although they performed comparably in discriminating weak-meter rhythms. The attenuated strong-meter advantage in children with SBM shows that their rhythm deficits occur at the level of both perception and action, and may represent a central processing disruption of the brain mechanisms for rhythm. (JINS, 2009, 15, 521–528.)