Abstract Oral stereognosis was measured in partially dentate and edentulous patients with stroke, Parkinson’s disease, and an age and gender-matched control group. Stereognostic tests involving conventional free intra-oral manipulation of test objects were undertaken in the par- tially dentate and edentulous with and without complete dentures. Comparisons were made using the unpaired t-test and ANOVA. Edentulous stroke patients without dentures had significantly greater error scores and fewer correct identifications compared with partially dentate stroke patients. Stereognostic measures were similar in the partially dentate and edentulous with dentures, with- in experimental groups. In the partially dentate, there were no differences in stereognostic measures between the three groups. Stereognostic measures were poorer in edentulous stroke patients with and without dentures compared with the edentulous control group. Partially dentate stroke patients are less likely to have impaired oral stereognosis than edentulous stroke patients. Keywords Edentulous · Oral stereognosis · Parkinson’s disease · Partially dentate · Stereognosis · Stroke Introduction Oral stereognosis is the ability to recognize the form of objects placed in the mouth [1]. It is a complex sensory phenomenon that involves sensory information from mu- cosal receptors, notably the tongue, and receptors in the lips, periodontium and temporomandibular joints [1, 2]. Changes in oral stereognosis contribute to the modula- tion of oral motor behaviour such as mastication and swallowing [3]. Oral stereognosis has been shown to de- cline with age and is affected by changes in dental condi- tion. Edentulous subjects appear to have impaired oral stereognostic ability compared with the completely den- tate [2, 4, 5]. Effective sensory input and integrated motor activity are essential for normal oral function [6]. In patients with stroke, limb paralysis and reduced manual dexterity are common physical features of the condition [7]. Oro- facial manifestations include unilateral facial palsy that mainly affects the lower face, the tongue and soft palate [7]. Discriminative sensory impairment such as poorer manual stereognosis often occurs in addition to motor deficit and can affect the functional outcome of the con- dition [7, 8, 9]. In Parkinson’s disease, tremor is com- mon and generally affects the hands, lips and tongue [7]. Bradykinesia is also a key feature and often involves the oro-facial muscles. At least 75% of patients have disor- dered speech or voice [10]. Furthermore, dysphagia has been identified in all phases of swallowing in Parkin- son’s disease patients [11]. In both these neurological conditions oral motor impairment can be disabling as speech, mastication and swallowing problems are com- mon [12, 13]. Recently, it was observed that oral stereog- nosis was poorer in edentulous stroke patients compared to edentulous Parkinson’s disease patients and a control group [14]. An improvement in stereognostic ability was noted in all three groups when dentures were worn [14]. Key features of effective stereognostic testing are the use of test objects of varying complexity but similar di- mensions, a standard format for administering test piec- es, the need to avoid extraneous noise during testing, and E.H.N. Pow · K.C.M. Leung · A.S. McMillan ( ✉ ) Oral Rehabilitation, Faculty of Dentistry, University of Hong Kong, 34 Hospital Road, Hong Kong e-mail: asmcmill@hkusua.hku.hk Fax: +852-28586114 M.C.M. Wong Faculty of Dentistry, University of Hong Kong, 34 Hospital Road, Hong Kong L.S.W. Li Rehabilitation Unit, Tung Wah Hospital, 12 Po Yan Street, Sheung Wan, Hong Kong S.-L. Ho Division of Neurology, Faculty of Medicine, University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong Clin Oral Invest (2001) 5:112–117 DOI 10.1007/s007840100110 ORIGINAL ARTICLE Edmond H.N. Pow · Katherine C.M. Leung Anne S. McMillan · May C.M. Wong Leonard S.W. Li · Shu-Leong Ho Oral stereognosis in stroke and Parkinson’s disease: a comparison of partially dentate and edentulous individuals Received: 10 October 2000 / Accepted: 13 March 2001 / Published online: 28 April 2001 © Springer-Verlag 2001