Our Recent Reports
In McNamara and Durso’s (2003) Pragmatic communication skills in Parkinson’s Disease, we found that relative to age-matched healthy controls, patients with PD were significantly impaired on measures of pragmatic communication abilities (p<.008). Pragmatic communication abilities comprise those verbal abilities that underlie social interactions (conversational appropriateness, topic maintenance, appropriate turn-taking, speech acts, stylistics, gestures, prosodics etc) and that are crucial for functional independence. We also found that PD patients were significantly unaware of the extent of their problems in these domains. We compared patient’s self-ratings of their own abilities with ratings of patient’s abilities obtained from their spouses. While patients reported no deficits, their spouses reported that patients evidenced significant deficits in all the major pragmatic domains. Our own ratings of patients’ abilities confirmed spouses’ claims of patient deficits. This is an extremely important clinical finding as unawareness may hinder attempts to overcome social communication problems. While noticeable clinically these pragmatic communication deficits in PD patients have never to our knowledge been systematically documented before. These pragmatic communication difficulties may translate into problems with communicating needs and desires and thus impairment in activities of daily living.
In McNamara, Durso and Auerbach’s (2002) Dopaminergic syndromes of sleep, mood and mentation: Evidence from Parkinson’s disease and related disorders, we presented evidence for a model of dopaminergic dysfunction in PD sleep dysfunction resulting in dis-inhibition of amygdalar activation and thus dis-inhibition of REM physiology. This dis-inhibition of REM physiology yields the well-known signs (excessive daytime sleepiness, reduced REM latencies, increased REM times, unpleasant dream content and nightmares etc) of sleep and mood dysfunction in parkinsonian syndromes.
In McNamara, Durso, Brown, and Lynch’s (2003) Counterfactual cognitive deficits in patients with Parkinson’s Disease, we examined ‘counterfactual’ cognitive functions in PD patients. Counterfactuals are mental representations of alternatives to past events, and recent research has shown them to be important for other cognitive processes such as planning, causal reasoning, problem-solving and decision-making. Most of these cognitive functions have been linked to the frontal lobes and are generally referred to as executive cognitive functions. Independent evidence suggests that some persons with Parkinson’s disease (PD) experience significant impairment on tasks involving executive functions (Taylor & Saint-Cyr, 1991). We therefore hypothesized that counterfactual thinking would be impaired in some persons with PD and would be linked to frontal dysfunction in these patients. To test this hypothesis we administered measures of counterfactual processing and frontal lobe functioning to persons with Parkinson’s Disease (PD) and age-matched healthy controls. We found that patients with PD were less likely to generate counterfactual thoughts after recalling a negative memory and in response to direct questions (M = .765 (.97)) than were control participants (M = 2.07 (1.7)), t (1, 27) =-2.62, p= .014). In addition, scores on the Counterfactual Inference Test (CIT) were significantly higher for controls (M=2.0 (1.2)) as compared to patients with PD (M=1.17 (.8)), t (l, 27)= -2.12, p = .043). The PD CIT scores were approximately what would be expected if the test options were selected at random (i.e., M = 1.32). We also found that PD patients selected their answers in a distinctly atypical pattern relative to the normative responses obtained in an original validating study of the test. Finally, PD performance on both the CF generation and inference tests correlated significantly with performance on two tests traditionally linked to frontal lobe functioning (Stroop color-word interference and Tower of London planning tasks) and one test of pragmatic social communication skills. We conclude that counterfactual thinking is impaired in PD and that this impairment may be related to frontal lobe dysfunction.
In McNamara, Durso and Brown’s (2003) Relation of ‘Sense of self’ to executive function in persons with Parkinson’s Disease, we hypothesized that the basic ‘sense of self’ or identity would change as a function of disease stage in PD and would predict functioning in PD. We also hypothesize that the sense of self would be related to frontal function in PD. Recent reports have linked impairment of various aspects of the sense of Self to frontal brain dysfunction. We therefore hypothesized that 1) the sense of Self would be impaired in some persons with PD and that 2) this impairment would change with disease stage and 3) be linked to frontal dysfunction. The standardized Loevinger sentence completion tests of identity development (‘self-test’), and measures of frontal lobe functioning were administered to twenty persons with PD and 10 age-matched healthy controls. We found that PD patients performed more poorly than controls on tests of executive function, and their ‘sense of self’ scores were significantly related to performance on measures of executive function while control’s responses were not. Analysis of the 160 self-test responses revealed a shift toward conformist responses in Hoehn-Yahr Stage III as compared to Stage II PD patients (see Table 2) though no mean self score differences obtained between PD patients and controls. While the ‘sense of self’ changes as a function of disease stage, the core experience of self in PD depends, in part, on frontal lobe function.
