Social cognition in cervical dystonia: phenotype and relationship to anxiety and depression

BACKGROUND AND PURPOSE

Anxiety and depression are common disabling comorbidities in cervical dystonia (CD) and may predispose to social withdrawal and social cognitive impairments. The relationship between social cognition and depressive/anxiety symptoms in CD is under-investigated.

METHODS

Forty-six CD patients (40 women; mean age ± SD, 55.57 ± 10.84 years) were administered the following social cognition battery: Affect Naming, Prosody Face and Pair Matching subtests from the Wechsler Adult Intelligence Scale IV and Wechsler Memory Scale IV (social perception), reality-known and reality-unknown false belief reasoning tasks (theory of mind), Empathy Quotient and Social Norms Questionnaire 22 (social behaviour), alongside the Benton Facial Recognition Task (non-emotional facial discrimination). Alongside CD severity, the Hospital Anxiety and Depression Scale measured depressive/anxiety comorbid diagnostic status and severity, and the Liebowitz Social Anxiety Scale assessed social phobia. Social cognition tasks were standardized using published normative data and a cut-off of z < -1.5 for impairment.

RESULTS

More than 90% of our CD patients performed normally on social perception and social behaviour tests. Performance on impaired belief reasoning (theory of mind) was impaired in 10 of 46 (21.74%); five of 46 (10.87%) were impaired on the Empathy Quotient. Better performance on the Affect Naming task was associated with comorbid anxiety (η²  = 0.09, medium-to-large effect size) and greater anxiety, depression and social phobia severity. Worse performance on the Empathy Quotient was associated with comorbid depression (η²  = 0.11, medium-to-large effect size) and greater depression severity. CD patients had significantly more difficulties with fearful face identification (P < 0.001).

CONCLUSIONS

Greater social perception abilities in CD patients with more severe anxiety and depression suggest efficient modulation and self-adaptation of social cognitive skills.

Characterization of cognition in mild cognitive impairment with and without Parkinson's disease

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Screening tests can diagnose PD-MCI but do not give detailed cognitive profiles.

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Criteria based on a complete neuropsychological battery identify more PD patients with MCI.

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The overall cognitive profile is similar in PD-MCI and MCI.

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Neuropsychological batteries and definition of impairment cut-offs should be refined.

Patterned cerebellar Purkinje cell death in a transgenic mouse model of Niemann Pick type A/B disease

Niemann Pick disease is a family of autosomal recessive disorders characterized by cholesterol accumulation. The most common type is Niemann Pick type A/B (NPA/B), resulting from deficient acid sphingomyelinase activity, which leads to sphingomyelin and cholesterol accumulation. The neuropathology of NPA/B includes widespread neuronal degeneration. An acid sphingomyelinase knockout mouse model of NPA/B (ASMKO) has been developed by the targeted deletion of the acid sphingomyelinase gene. When cerebellar morphology was examined in the ASMKO mouse at postnatal day 60 (P60), a dramatic pattern of longitudinal stripes was revealed in which roughly half the Purkinje cells had died, leaving a highly stereotyped, bilaterally symmetrical array of stripes. Antizebrin II immunocytochemistry revealed that the absent Purkinje cells corresponded exactly to the zebrin II-negative subset, leaving the zebrin II-positive subset apparently intact. By P120, some of the zebrin II-positive Purkinje cells had also been eliminated from the posterior vermis and hemispheres. By P180, all Purkinje cells had been lost from the anterior lobe. Finally at P240, almost all Purkinje cells had disappeared to leave a stereotyped distribution in lobules VI, IX-X and the flocculus and paraflocculus. The temporal pattern of Purkinje cell death demonstrates differential susceptibility of morphologically identical cells that appear to be linked to their molecular phenotypes.

Paw and limb use in skilled and spontaneous reaching after pyramidal tract, red nucleus and combined lesions in the rat: behavioral and anatomical dissociations

The pyramidal tract and red nucleus send prominent projections to the spinal cord and are thought to co-operate in producing skilled movements. In the present study, skilled reaching for food located on a shelf and spontaneous grasping, handling and eating pieces of pasta were video-recorded and analyzed in control rats, rats with unilateral ibotenic acid lesions of the red nucleus (RN), unilateral pyramidal tract lesions (PT) and combined lesions. The behavioral results suggest that skilled movements are organized as action patterns, easily recognizable and distinctive for each task. In both skilled and spontaneous reaching, PT lesions reduced success more than RN lesions, suggesting a greater role for the PT in guiding limb movements. Both lesions impaired rotatory movements including limb aiming, pronation and supination. RN lesions additionally abolished the arpeggio movement by which the paw is oriented for searching and grasping. Combined lesions were additive as rats lost both rotatory movements and arpeggio. Nevertheless, even after combined lesions, the rats were able to advance the limb, grasp food and withdraw the limb. The sparing following combined lesions suggests that other neural systems as well as compensatory adjustments assist the impaired limb. The results are discussed in relation to the possible distinctive contributions of the rubrospinal and corticospinal tract to the action patterns that comprise skilled movements in rats.