Effectiveness of low-dose pregabalin in three patients with Lewy body disease and central neuropathic pain

Tactile hallucinations in dementia with Lewy bodies

BACKGROUND

Visual hallucinations (VH) are one of the most common psychological symptoms of dementia with Lewy bodies (DLB). It is generally considered that the VH that occur in DLB usually disappear when patients try to touch imaginary objects. However, DLB patients also sometimes experience tactile hallucinations (TH). To the best of my knowledge, this is the first report to comprehensively describe the TH experienced by DLB patients.

METHODS

I searched the literature for case reports that described TH in Parkinson's disease (PD), PD dementia, or DLB. There were four reports regarding TH in PD, one of which was a review article published in 2017. I described the clinical courses of five representative cases of DLB in which TH were associated with VH, and then compared the characteristics of the TH experienced in DLB with those of the TH encountered in previously reported cases of PD.

RESULTS

The TH experienced by the DLB patients had very similar characteristics to the TH experienced by PD patients. However, the TH of the DLB patients differed from those of PD patients in the following respects: (i) when the DLB patients tried to touch the imaginary objects, they often did not disappear; (ii) the imaginary objects experienced by the DLB patients sometimes exhibited characteristic hardness and temperature; and (iii) the imaginary objects experienced by the DLB patients were often influenced by the patients' behaviour, which in turn led to further hallucinations.

CONCLUSIONS

Based on the abovementioned characteristics of the hallucinations of DLB patients, I propose that these phenomena represent a novel psychopathological entity, which I shall temporarily refer to as, 'strengthening of VH by TH'.

Vocally disruptive behavior: A case report and literature review

Vocally disruptive behavior (VDB) is a common and particularly difficult symptom to manage in dementia. VDB is usually considered collectively with agitation and aggression as a component of behavioral and psychological symptoms in dementia and is therefore poorly understood as an individual symptom. A review of the literature is described where VDB as a challenging behavior has been individually examined as a symptom. A case of VDB occurring in patient with dementia is described where the patient's repetitive vocalizations responded to treatment with pregabalin. This has not been previously reported in the literature. The prevalence of VDB, the factors associated with it and the current management guidelines for clinicians are outlined with a review of the drug treatment strategies for VDB. Pregabalin with its unique pharmacological profile and excellent tolerability should be considered as a possible treatment for VDB where drug treatment is indicated.

Possible effectiveness of low-dose pregabalin in a patient suffering from Lewy body disease and chronic pruritus

Many patients with Lewy body disease (LBD) complain of pain, although the detailed mechanism responsible for LBD-related pain remains to be clarified. Moreover, there does not appear to be any reports about LBD patients suffering from an itching sensation. In this report, the case of an LBD patient who experienced severe itching that persisted for over 6 months, which was treated successfully with low-dose pregabalin therapy, is described. This is the first study to report the effects of low-dose pregabalin, which has been used to treat LBD-related pain, to treat itching in a patient with LBD.