Assessment of deep brain stimulation candidacy during the COVID-19 pandemic: Lessons learned and future directions for neuropsychologists.

ObjectiveNeuropsychological assessment is integral to the pre-surgical deep brain stimulation (DBS) workup for patients with movement disorders. The COVID-19 pandemic quickly affected care access and shifted healthcare delivery, and neuropsychology has adapted successfully to provide tele-neuropsychological (teleNP) DBS evaluations during this time, thus permanently changing the landscape of neuropsychological practice. Method: In this paper, we discuss the lessons learned from the pandemic and we offer care management guidelines for teleNP and in-person evaluations of pre-DBS populations, with exploration of the feasibility of the different approaches for uninterrupted care access. Results: We summarize the strengths and weaknesses of these care models and we provide future directions for the state of clinical neuropsychological practice for DBS programs, with implications for broader patient populations. Conclusions: A better understanding of these dynamics will inform and educate the DBS team and community regarding the complexities of performing DBS neuropsychological evaluations during COVID-19 and beyond.

The global pandemic has permanently changed the state of practice for pre-DBS neuropsychological evaluations.

The evaluation and management of patients with movement disorders has evolved considerably due to the COVID-19 pandemic, including the assessment of candidates for deep brain stimulation (DBS) therapy. Members of the Neuropsychology Focus Group from the Parkinson Study Group Functional Neurosurgical Working Group met virtually to discuss current practices and solutions, build consensus, and to inform the DBS team and community regarding the complexities of performing DBS neuropsychological evaluations during COVID-19. It is our viewpoint that the practice of neuropsychology has adapted successfully to provide tele-neuropsychological pre-DBS evaluations during the global pandemic, thus permanently changing the landscape of neuropsychological services.

No evidence of risk-taking or impulsive behaviour in a person with episodic amnesia: Implications for the role of the hippocampus in future-regarding decision-making.

Does advantageous decision-making require one to explicitly remember the outcome of a series of past decisions or to imagine future personal consequences of one's choices? Findings that amnesic people with hippocampal damage cannot form a clear preference for advantageous decks over many learning trials on the Iowa Gambling Task (IGT) have been taken to suggest that complex decision-making on the IGT depends on declarative (episodic) memory and hippocampal integrity. Alternatively, impaired IGT performance in amnesic individuals could be secondary to risk-taking and/or impulsive behaviour resulting from impaired episodic future thinking (i.e. prospection) known to accompany amnesia. We tested this possibility in the amnesic individual K.C. using the IGT and the Toronto Gambling Task (TGT), a novel task that dissociates impulsivity from risk-taking without placing demands on declarative memory. K.C. did not develop a preference for advantageous over disadvantageous decks on the IGT and, instead, showed a slight preference for short-term gains and an inability to acquire a more adaptive appreciation of longer-term losses. He also did not display impulsive or risk-taking behaviour on the TGT, despite a profound inability to imagine personal future experiences. These findings suggest that impaired decision-making on the IGT in amnesia is unlikely to reflect a predilection to act in the moment or failure to take future consequences into account. Instead, some forms of future-regarding decision-making may be dissociable, with performance on tasks relying on declarative learning or on episodic-constructive processes more likely to be impaired.

A magnetoencephalography study of multi-modal processing of pain anticipation in primary sensory cortices.

Pain anticipation plays a critical role in pain chronification and results in disability due to pain avoidance. It is important to understand how different sensory modalities (auditory, visual or tactile) may influence pain anticipation as different strategies could be applied to mitigate anticipatory phenomena and chronification. In this study, using a countdown paradigm, we evaluated with magnetoencephalography the neural networks associated with pain anticipation elicited by different sensory modalities in normal volunteers. When encountered with well-established cues that signaled pain, visual and somatosensory cortices engaged the pain neuromatrix areas early during the countdown process, whereas the auditory cortex displayed delayed processing. In addition, during pain anticipation, the visual cortex displayed independent processing capabilities after learning the contextual meaning of cues from associative and limbic areas. Interestingly, cross-modal activation was also evident and strong when visual and tactile cues signaled upcoming pain. Dorsolateral prefrontal cortex and mid-cingulate cortex showed significant activity during pain anticipation regardless of modality. Our results show pain anticipation is processed with great time efficiency by a highly specialized and hierarchical network. The highest degree of higher-order processing is modulated by context (pain) rather than content (modality) and rests within the associative limbic regions, corroborating their intrinsic role in chronification.

Predictors of decline in verbal fluency after frontal lobe epilepsy surgery.

Few studies have focused on language changes following frontal lobe epilepsy (FLE) surgery. The aim of the current study is to quantify the role of resection location and size in verbal fluency decline after FLE surgery and to examine its predictors. A retrospective chart review identified 36 adult patients who underwent FLE surgery. Verbal fluency was assessed using the Controlled Oral Word Association Test (COWAT). Nine (25%) of the patients had significant decline. Binary logistic regression incorporating side of resection and preoperative COWAT score significantly predicted decline and accounted for 25% of the variance. A trend was also noted for decliners to have higher postoperative seizure recurrence (p=0.067). There was no effect of size of resection. Patients undergoing FLE surgery are at risk of verbal fluency decline, especially if they have a high presurgical verbal fluency score, undergo a frontal lobe resection in the language dominant hemisphere, and have poor seizure outcome.

Impulsivity and risk-taking behavior in focal frontal lobe lesions.

Frontal lobe dysfunction may underlie excessively impulsive and risky behavior observed in a range of neurological disorders. We devised a gambling task to examine these behavior tendencies in a sample of patients who had sustained focal damage to the frontal lobes or nonfrontal cortical regions as well as in a matched sample of healthy control subjects. The main objectives of the study were: (1) to behaviorally dissociate impulsivity and risk-taking; (2) to examine potential associations between specific frontal lesion sites and impulsivity or risk-taking; (3) to investigate the influence of reinforcement and trial timing on both behaviors. Our results indicated that patients and controls were equally likely to perform impulsively. Risk-taking performance strategies, however, were related to left ventrolateral and orbital lesion sites. Moreover, risk-taking was also associated with blunted response alteration following a nonrewarded trial. Patients and control subjects showed identical responses to reward-timing manipulations consistent with formal decision-making theory. These findings suggest that ventrolateral and orbital lesions are related to the reward-based aspects of decision-making (risk-taking) rather than to simple response disinhibition (impulsivity). Reduced reaction to the negative consequences of one's actions may underlie this behavior pattern.

Stroop performance in focal lesion patients: dissociation of processes and frontal lobe lesion location.

There were three primary objectives: to examine the usefulness of the Stroop interference effect as a measure of frontal lobe function; to investigate the possibility of distinct lesion effects for word reading or color naming; and to specifically determine the brain regions necessary for the performance of the incongruent condition. Fifty-one patients with single focal brain lesions in frontal and non-frontal regions and 26 normal control subjects (CTL) were administered the word reading, color naming and incongruent conditions of the Stroop task. Only frontal lesions produced significant impairment. Patients with posterior lesions were not significantly deficient in any condition. Damage to the left dorsolateral frontal lobe resulted in increased errors and slowness in response speed for color naming. Contrary to Perret (Neuropsychology, 1974; 12: 323-330), lesions of the left frontal lobe did not result in a selective interference deficit on the Stroop incongruent condition. Rather, bilateral superior medial frontal damage was associated with increased errors and slowness in response time for the incongruent condition. This result is interpreted as failure of maintenance of consistent activation of the intended response in the incongruent Stroop condition. The results and conclusion are compatible with the prevalent theories of both the Stroop effect and the role of the superior medial frontal regions. The role of the anterior cingulate cortex on performance of the Stroop task is likely related to task and patient context.