Joohi Shahed

Baylor College of Medicine, Houston, TX, United States

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Publications (9)29.52 Total impact

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    ABSTRACT: Mutations in the parkin gene and the PTEN-induced putative kinase 1 gene (PINK1) have been identified as the most common causes of autosomal recessive early-onset Parkinson disease (EOPD). To investigate the presence of the parkin and PINK1 gene mutation(s) and to explore genotype-phenotype correlations in American Caucasian families with EOPD from North American, we screened these two genes in probands of six families by direct sequencing, semi-quantitative PCR and RT-PCR. No PINK1 gene mutation was found in any of the probands, but compound heterozygous mutations (EX 3 del and EX 3_4 del) in the parkin gene were identified in one family. Extended analysis of the parkin-positive family showed the phenotype of patients was that of classic autosomal recessive EOPD, characterized by early age at onset, slow progression, beneficial response to levodopa, and levodopa-related motor complications. Three heterozygous mutation carriers (EX 3 del or EX 3_4 del) were free of any neurological symptoms. None of 62 healthy controls harbored EX 3 del or EX 3_4 del mutation. Our data suggest that compound heterozygous mutations (EX 3 and EX 3_4 del) in the parkin gene were the cause of EOPD in one of six Caucasian families; heterozygous EX 3 del and heterozygous EX 3_4 del forms were insufficient to cause this disorder, consistent with a loss-of-function mechanism of the parkin mutations. The results may provide new insights into the cause and diagnosis of PD and have implications for genetic counseling.
    Neuroscience Letters 02/2008; 430(1):18-22. · 2.03 Impact Factor
  • Alan Diamond, Joohi Shahed, Joseph Jankovic
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    ABSTRACT: Deep brain stimulation (DBS) of the ventral intermediate (Vim) nucleus of the thalamus has been the target of choice for patients with disabling essential tremor or medication refractory parkinsonian tremor. Recently there is evidence that the subthalamic nucleus (STN) should be the targets for patients with tremor associated with Parkinson's disease (PD). To assess the effects of STN DBS on parkinsonian tremor, eight consecutive patients with PD and disabling tremor were videotaped using a standardized tremor protocol. Evaluations were performed at least 12 h after last dose of medication with the DBS turned off followed by optimal DBS on state. A rater blinded to DBS status evaluated randomized video segments with the tremor components of the Unified Parkinson Disease Rating Scale (UPDRS) and Tremor Rating Scale (TRS). Compared with DBS off state there were significant improvements in mean UPDRS tremor score 79.4% (p=0.008), total TRS score 69.9% (p=0.008) and upper extremity 92.5% (p=0.008) TRS subscore. Functional improvement was noted with pouring liquids. Our findings provide support that STN DBS is an effective treatment of tremor associated with PD.
    Journal of the Neurological Sciences 10/2007; 260(1-2):199-203. · 2.24 Impact Factor
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    ABSTRACT: The aim of this work was to draw attention to potentially life-threatening symptoms associated with Tourette syndrome (TS) and to explore their relationship to TS comorbidities. Medical records of all patients with TS evaluated at our Movement Disorders Clinic between July 2003 and July 2006 were reviewed. Data on patients with malignant TS, defined as >or=2 emergency room (ER) visits or >or=1 hospitalizations for TS symptoms or its associated behavioral comorbidities, were entered into a dataset and analyzed. Five illustrative cases are described. Of 333 TS patients evaluated during the 3-year period, 17 (5.1%) met the criteria for malignant TS. Hospital admission or ER visits were for tic-related injuries, self-injurious behavior (SIB), uncontrollable violence and temper, and suicidal ideation/attempts. Compared with patients with nonmalignant TS, those with malignant TS were significantly more likely to have a personal history of obsessive compulsive behavior/disorder (OCB/OCD), complex phonic tics, coprolalia, copropraxia, SIB, mood disorder, suicidal ideation, and poor response to medications. Although TS is rarely a disabling disorder, about 5% of patients referred to a specialty clinic have life-threatening symptoms. Malignant TS is associated with greater severity of motor symptoms and the presence of >or=2 behavioral comorbidities. OCD/OCB in particular may play a central role in malignant TS; obsessive compulsive qualities were associated with life-threatening tics, SIB, and suicidal ideation. Malignant TS is more refractory to medical treatment than nonmalignant TS.
    Movement Disorders 09/2007; 22(12):1743-50. · 4.56 Impact Factor
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    Joohi Shahed, Joseph Jankovic
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    ABSTRACT: Although essential tremor (ET) and Parkinson's disease (PD) are considered distinct disorders, there is overlap in some clinical features. In some PD patients, a long-standing postural tremor in the hands may precede the onset of parkinsonian features by several years or decades. Furthermore, large families with both ET and PD phenotypes have been described and autopsy studies have demonstrated Lewy body pathology in brains of ET patients. Functional neuroimaging suggests that some ET patients have dopaminergic deficit. We examine here the evidence for and against an association between ET and PD, and critically review data supporting the notion that a subset of ET patients is predisposed to developing PD.
    Parkinsonism & Related Disorders 04/2007; 13(2):67-76. · 3.27 Impact Factor
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    Neurology 02/2007; 68(2):159-60. · 8.30 Impact Factor
  • Joohi Shahed, Joseph Jankovic
    Handbook of Clinical Neurology 02/2007; 83:329-42.
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    ABSTRACT: Globus pallidus deep brain stimulation (GPi-DBS) is a useful alternative in the treatment of dystonia. Patients selected for GPi-DBS were prospectively rated with the Unified Dystonia Rating Scale (UDRS). Also, "blinded" videotape assessments were performed. Eleven patients were identified. Compared with pre-DBS scores, there were improvements in mean total UDRS score (15.3%) and in the following subscores: neck (18.18%), trunk (32.9%), arm (17.9%), and leg (19.9%). One patient developed a skin infection and erosion requiring surgical debridement. GPi-DBS is a safe and effective treatment for generalized dystonia in patients who remained impaired, despite optimal medical therapy.
    Movement Disorders 06/2006; 21(5):692-5. · 4.56 Impact Factor
  • Joohi Shahed, Joseph Jankovic
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    ABSTRACT: To characterize speech patterns in patients with Parkinson's disease (PD) who have a history of childhood stuttering. Childhood stuttering usually resolves, but it re-emerges in some patients after stroke or other brain disorders. This phenomenon of recurrent stuttering has not been characterized in childhood stutterers who later develop PD. Twelve patients with a history of childhood stuttering that remitted and subsequently recurred were included in the study. A structured interview was administered to seven patients, and six were able to answer questions about childhood stuttering. The Johnson Severity Scale (JSS) (range 0-7) and a Situation Avoidance Scale (SAS) were used to rate stuttering severity (range 0-15) and avoidance (range 0-15). The mean age at onset of childhood stuttering was 6.2 years (range 5-10); the mean latency from the onset of childhood stuttering to adult stuttering was 46.1 years; and the stuttering recurred on average 5.9 years (range 0-21) after the onset of PD. The stuttering characteristics in childhood and adulthood included repetitions of sounds and syllables at the beginnings of words, blocks and interjections, physical tension, and a worsening of symptoms with stress. The patients rated themselves as having mild-to-moderate childhood stuttering by the JSS (mean 3.0, range 2-4) and mild-to-moderate stuttering and avoidance by the SAS (mean stuttering score 5.3, range 3-7; mean avoidance score 4.2, range 3-6). There was no apparent association between the severity of childhood stuttering and the severity of PD, but those patients who had higher Unified Parkinson's Disease Rating Scale scores tended to have more and worse symptoms of stuttering. Our patients provide evidence for the hypothesis that childhood stuttering may re-emerge in adulthood with the onset of PD.
    Movement Disorders 02/2001; 16(1):114-8. · 4.56 Impact Factor
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    ABSTRACT: BACKGROUND: Craving sweets is common in patients with Parkinson's disease (PD), but this symptom has not been systematically studied. METHODS: Patients with idiopathic PD and unaffected spouses of PD patients completed a Food Frequency Questionnaire (FFQ) for sweet foods they eat now, and identified if they felt craving for any of them. If yes, they completed a Food Craving Questionnaire (FCQ). All subjects answered a Symptom Checklist focusing on depression, anxiety, and obsessive-compulsive disorder, and completed smell testing (Q-SIT) and taste threshold testing for sweet, salty, sour, and bitter substances. PD subjects also completed an FFQ and FCQ relating to symptoms before developing PD. Demographic data was recorded. RESULTS: 62 patients (mean age 64.4 yrs, 35 male) and 23 controls (mean age 64.4 yrs, 7 male) were enrolled. Mean PD duration was 7.1 yrs (SD 4.9 yrs), mean UPDRS Part 3 score (N=50) was 26.7 (SD 12.2), and mean Hoehn &Yahr stage was 1.9 (SD 0.6). Of the 85 subjects, 32 (51.6%) patients and 9 (39.1%) controls identified themselves as cravers (p=0.32). Of those stating they craved sweets, 11 PD patients (34.4%) scored over the 75th percentile on the FCQ (mean 5.9, SD 0.5) but only 1 control (11.1%) scored over the 75th percentile (p=0.17). Craving did correlate with duration of PD (p=0.04), but no correlation was found between craving and age, gender, levodopa equivalents, depression, anxiety, OCD, QSIT scores, or craving before PD diagnosis. Thresholds for all tastes were similar between PD patients and controls, all subjects had relatively preserved sense of taste for sweets, and QSIT scores were lower for all PD patients than controls (p<0.0005). CONCLUSIONS: This pilot study demonstrates that a higher proportion of PD patients identified themselves as craving sweets than controls, and a higher proportion scored over the 75th percentile on a score of craving. Craving sweets significantly correlated with duration of PD, but not with other factors. Sense of smell and taste did not affect craving. Larger studies are needed to further define craving sweets in PD, and to correlate craving with other behaviors such as obsessive-compulsive disorder. Craving for sweets in PD may be an expression of dopamine-mediated reward systems.